First Report of Phytophthora taxon niederhauserii Causing Root and Stem Rot of Mimosa in Italy

Mimosa [Acacia dealbata Link, syn. Acacia decurrens (Wendl. F.) Wild. var. dealbata (Link) F. Muell., Fabaceae] is an evergreen shrub native to southeastern Australia that is cultivated as an ornamental plant in warm temperate regions of the world. In spring 2010, in a commercial nursery in Liguria (northern Italy), 6- to 10-month-old potted plants of A. dealbata showed symptoms of sudden collapse, defoliation, and wilt associated with root and basal stem rot. An abundant gum exudate oozed from the basal stem. A Phytophthora species was consistently isolated from roots and stem on BNPRAH selective medium (4). On V8 agar (V8A), axenic cultures obtained by single hyphal transfers formed stellate to radiate colonies with aerial mycelium whereas on potato dextrose agar (PDA) the colonies grew more slowly than on V8A and showed stoloniform mycelium and irregular margins. Minimum and maximum growth temperatures on PDA were 10 and 35°C, with the optimum at 30°C. In water, all isolates produced catenulate or single fusiform hyphal swellings and ellipsoid, nonpapillate, persistent sporangia. Dimensions of sporangia were 46.1 to 65.4 × 23.1 to 30.8 μm (mean l/b ratio 2.1). All isolates were A1 mating type and produced spherical oogonia with amphyginous antheridia when paired with A2 mating type of P. drechsleri Tucker on V8A plus β-sytosterol (4). Internal transcribed spacer (ITS) regions of rDNA of the representative Phytophthora isolate IMI 500394 from A. dealbata were amplified and sequenced in both directions with primers ITS6/ITS4. The consensus sequence (GenBank Accession No. JF900371) was 99% similar to sequences of several isolates identified as Phytophthora taxon niederhauserii Z.G. Abad and J.A. Abad (e.g., GQ848201 and EU244850). Pathogenicity tests were performed on 1-year-old potted plants of A. dealbata with isolate IMI 500394. Twenty plants were transplanted into pots (12-cm-diameter) filled with soil infested (4% v/v) with the inoculum of IMI500394 produced on kernel seeds. Plants were kept in a greenhouse with natural light at 25 ± 2°C and watered to field capacity weekly. All inoculated plants showed symptoms of wilt, leaf chlorosis, and basal stem rot within 3 to 4 weeks. Twenty control plants transplanted in autoclaved soil mix remained healthy. P. taxon niederhauserii was reisolated solely from inoculated plants, thus fulfilling Koch's postulates. Since 2003, this pathogen has been found on bottlebrush and rock rose grown in a nursery in Sicily (southern Italy), as well as on Banksia in a nursery in Liguria (2,3). To our knowledge, this is the first report of P. taxon niederhauserii on A. dealbata. P. taxon niederhauserii, recently described as P. niederhauserii sp. nov. (1), is a polyphagous pathogen that was originally reported on arborvitae and ivy in North Carolina in 2001. References: (1) Z. G. Abad et al. Mycologia (in press), 2013. (2) S. O. Cacciola et al. Plant Dis. 93:1075, 2009. (3) S. O. Cacciola et al. Plant Dis. 93:1216, 2009. (4) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.

First Report of Phytophthora × pelgrandis Causing Root Rot and Lower Stem Necrosis of Common Box, Lavender and Port-Orford-Cedar in Hungary

In 2008 and 2009, necrotic bark lesions at the root collar and lower stem associated with root rot, reduced growth, and wilting were observed on container-grown common box (Buxus sempervirens L.), lavender (Lavandula angustifolia Mill. 'Hidcote'), and Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murray) Parl. 'Columnaris') in three ornamental nurseries in western Hungary. Number of affected plants ranged from approximately 100 (Port-Orford-cedar) to 250 (lavender). Isolations from necrotic root collars of each host plant species yielded four Phytophthora isolates developing uniform colonies on carrot agar with a maximum growth temperature of 35 to 36°C. The isolates were homothallic with smooth-walled oogonia (32.2 ± 2.3 to 35.9 ± 3.5 μm), aplerotic oospores (27.5 ± 1.8 to 32.1 ± 3.1 μm) and both amphigynous and paragynous antheridia, and produced chlamydospores (25.8 ± 3.9 to 29.1 ± 5.2 μm) and papillate sporangia (35.2 ± 2.5 to 43.5 ± 5.6 μm long and 27.6 ± 2.2 to 32.0 ± 3.8 μm wide), mostly obpyriform to nearly spherical or rarely distorted with two or three apices. In spring water, sporangia were both caducous with short pedicel and non-caducous. Multiplex ITS-PCR assay of DNA from all isolates, using primers specific for P. nicotianae (NICF1 and NICR2.1) and P. cactorum (CACTF1 and CACTR1) (1), amplified DNA fragments of the expected size for each Phytophthora species. In addition, isoenzyme analysis revealed a characteristic banding pattern of one heterodimer and two homodimer bands at both loci of the dimeric enzyme malate dehydrogenase. These bands comigrated with those of P. × pelgrandis (Gerlach et al.) (CBS 123385) and isolate PD 93/1339 (courtesy of W. A. Man in 't Veld), two natural hybrid strains of P. nicotianae and P. cactorum (2,3), proving that our four isolates can be referred to as this interspecific hybrid. Pathogenicity was tested on 1- or 3-year-old plants of the original host species and cultivars (for common box, cv. Faulkner was used). Cultures were grown for 4 to 6 weeks at 20°C on autoclaved millet grains moistened with V8 broth. Infested and uninfested grains were mixed with autoclaved soil in a ratio of 6% (w/v), and the mixes were used as potting media for transplanting five treated and five control plants per isolate, respectively. Plants were kept in a growth chamber (20°C, 70% RH, 12-h photoperiod). Pots were flooded for 24 h on the 1st and 21st day after transplanting. All plants in infested potting mix showed symptoms of wilt associated with basal stem and root necrosis, similar to those observed on the plants from the field, within 2 and 3 months on lavender and both common box or Port-Orford-cedar, respectively. Additionally, a reduction of root weight ranging from 35 to 68% compared to the control was recorded. Growth reduction was significant at P ≤ 0.019 according to Mann Whitney test. Control plants remained healthy. The same Phytophthora hybrid was reisolated solely from inoculated plants. In Europe, hybrid isolates of P. nicotianae × P. cactorum have been reported on several ornamental plants, including lavender, in the Netherlands and Germany (2,3). However, to our knowledge, this is the first report of this hybrid in Hungary and as a pathogen of common box and Port-Orford-cedar in the world. References: (1) P. J. M. Bonants et al. Phytopathology 90:867, 2000. (2) W. A. Man in 't Veld et al. Phytopathology 88:922, 1998. (3) H. I. Nirenberg et al. Mycologia 101:220, 2009.

Bud and Root Rot of Windmill Palm (Trachycarpus fortunei) Caused by Simultaneous Infections of Phytophthora palmivora and P. nicotianae in Sicily

In June 2009 in a commercial nursery in eastern Sicily (Italy), 3-year-old potted windmill palms (Trachycarpus fortunei (Hooker) H. Wendl.) showed a decline in growth, wilt, droop, and basal rot of the youngest leaves. The rot progressed inward and killed the bud. Initially, older leaves remained green but eventually the entire plant collapsed. Root rot was consistently associated with aboveground symptoms. Two Phytophthora species were consistently isolated from the petiole base, heart, roots, and rhizosphere soil of symptomatic plants on a selective medium (2) and occasionally recovered from roots and rhizosphere soil of asymptomatic plants. Pure cultures were obtained by single-hypha transfers and the two species were identified on the basis of morphological and molecular characters as Phytophthora palmivora and P. nicotianae. Both species were recovered from all symptomatic plants. From multiple tissue samples per plant, we recovered either or both species. On potato dextrose agar (PDA), P. palmivora isolates grew between 10 and 35°C, with the optimum at 27°C. On V8 juice agar, they produced elliptical to ovoid, papillate, caducous sporangia (32 to 78 × 23 to 39 μm) with a mean length/breadth (l/b) ratio of 1.8:1 and a short pedicel (mean pedicel length = 5 μm). Isolates of P. nicotianae produced arachnoid colonies on PDA, grew at 37°C but did not grow at 40°C. Sporangia (29 to 55 × 23 to 45 μm) were spherical to ovoid (l/b ratio 1.3:1), papillate and often bipapillate, and noncaducous. Isolates of both species produced amphigynous antheridia and oogonia only when paired with reference isolates of P. nicotianae of the A2 mating type. The internal transcribed spacer (ITS) region of rDNA of two isolates of P. palmivora (IMI 398987 and IMI 398988) and an isolate of P. nicotianae (IMI 398989) from T. fortunei was amplified with primers ITS6/ITS4 and sequenced (1). Blast analysis of the sequences of isolates IMI 398987 and IMI 398988 (GenBank Accession Nos. HQ596556 and HQ596558) showed 99% homology with the sequence of two reference isolates of P. palmivora (GQ398157.1 and GU258862), while the sequence of isolate IMI 398989 (HQ596557) showed 99% homology with a reference isolate of P. nicotianae (EU331089.1). Pathogenicity of isolates IMI 398987 and IMI 398989 was proved by inoculating separately each isolate on 1-year-old potted plants of T. fortunei (10 plants per isolate). A zoospores suspension (2 × 10⁴ zoospores/ml) was pipetted onto the petiole base of the three central leaves (200 μl per leaf) of each plant. Sterile water was used for control plants. All plants were incubated at 25 ± 2°C with 100% humidity for 48 h and then maintained in a greenhouse at 24 to 28°C. Within 3 weeks, all inoculated plants showed symptoms of bud rot. Control plants remained healthy. P. palmivora and P. nicotianae were reisolated only from inoculated plants. Bud rot of palms caused by P. palmivora was reported previously in Italy (3). However, to our knowledge, this is the first report of simultaneous infections of P. palmivora and P. nicotianae as causal agents of this disease. Outbreak of bud rot may have been favored by overhead sprinkler irrigation. The recovery of P. palmivora and P. nicotianae from rhizosphere soil and roots of asymptomatic plants suggests infested soil was the primary inoculum source. References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) A. Pane et al. Plant Dis. 91:1059, 2007.

Root and Basal Stem Rot of Rose Caused by Phytophthora citrophthora in Italy

Approximately 800 ha of cut flower roses are cultivated for commercial production in Italy. During autumn of 2004 in an experimental greenhouse in western Sicily (southern Italy), 60% of 2-year-old plants of rose cv. Red France on Rosa indica cv. Major rootstock grown in soil showed leaf chlorosis and wilt. A dark brown lesion lined by a water-soaked area was noticeable at the stem base near the soil surface. Root rot was found consistently associated with aboveground symptoms and plants collapsed within 4 months after the appearance of the first symptoms. The same symptoms were observed sporadically on rose plants of the same cultivar during the last 6 years in commercial nurseries in western Sicily. In all cases, a Phytophthora species has been consistently isolated from rotted roots and stems on Phytophthora-selective media. Pure cultures were obtained by single-hypha transfers. The species was identified as Phytophthora citrophthora on the basis of morphological characters and electrophoretic analysis of mycelial proteins on polyacrylamide gel (1). On potato dextrose agar, isolates produced petaloid colonies with optimum growth temperature at 25°C. On V8 agar, mono- and occasionally bipapillate, ovoid to limoniform sporangia, measuring 44 to 55 × 27 to 28 μm, with a mean length/breadth ratio of 1.4:1 were produced. All isolates were heterothallic but did not produce gametangia in dual cultures with P. nicotianae isolates of A1 and A2 mating type. Electrophoretic patterns of total mycelial proteins and four isozyme (acid and alkaline phosphatases, esterase, and malato dehydrogenase) of the isolates from rose were identical to those of reference isolates of P. citrophthora, but clearly distinct from isolates of other heterothallic species with papillate sporangia, including P. capsici, P. nicotianae, P. palmivora, and P. tropicalis. All isolates from rose showed the same electrophoretic profiles. Blast search of rDNA-ITS sequence from PCR-amplified ITS4/ITS6 primers (2) of a representative isolate from rose (IMI 392044) showed 98% homology with a reference isolate of P. citrophthora (GenBank No. EU0000631), thus confirming the identification. Pathogenicity of isolate IMI 392044 was tested on 10 12-month-old plants of rose cv. Red France grafted on R. indica cv. Major transplanted in pots containing a mixture of sphagnum peat moss and sandy loam soil (1:1 vol/vol) infested with 80 g of inoculum per liter of mixture. Inoculum was produced by growing the isolate on wheat kernels. Plants transplanted in pots containing noninfested soil served as controls. Plants were kept in a greenhouse at 22 ± 3°C and watered to soil saturation once a week. Inoculated plants developed symptoms of leaf chlorosis and root and crown rot within 15 to 30 days and wilted within 40 to 80 days after inoculation. Control plants remained healthy. P. citrophthora was consistently reisolated from inoculated plants. Root and basal stem rot of rose may be caused by several Phytophthora spp. and has been reported in various countries of Asia, Europe, and North America (3,4). However, to our knowledge, this is the first report in Italy. The occurrence of this disease may be attributed to excessive irrigation practices. References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) Y. Nagai et al. Phytopathology 68:684, 1978. (4) B. W. Schwingle et al. Plant Dis. 91:97, 2007.

First Report of Root and Basal Stem Rot Caused by Phytophthora nicotianae on Tree Aeonium (Aeonium arboreum) in Italy

The genus Aeonium, family Crassulaceae, comprises approximately 35 species that are native to northern Africa and the Canary Islands. Tree aeonium (Aeonium arboreum (L.) Webb & Berthel.) is a bushy, perennial succulent with rosettes of tender, waxy leaves at the apex of few-branched or occasionally single, naked stems. Mature rosettes bear yellowish inflorescences. Aeoniums are cultivated as ornamentals in gardens and containers. During the summer of 2009, in a garden in eastern Sicily (southern Italy), 3-year-old potted plants of tree aeonium showed stunting, shrivelling, and chlorosis of leaves and drop of external leaves associated with root and basal stem rot. Drops of an amber exudate oozed from the basal stem. Tissues of the basal stem were soft, but no external necrosis was visible. A species of Phytophthora was consistently isolated from symptomatic roots and basal stem tissues on a medium selective for Oomycetes (2). Axenic cultures were obtained by single-hypha transfers. The pathogen was identified by morphological criteria as Phytophthora nicotianae B. de Haan; it formed stoloniferous colonies on potato dextrose agar and grew between 8 and 38°C, with the optimum at 30°C. On V8 juice agar it produced spherical, intercalary chlamydospores (mean diameter of 26 μm) and persistent, mono- and bipapillate, spherical to ovoid, ellipsoid, obpyriform sporangia that measured 29 to 56 × 22 to 45 μm with a mean length/breadth ratio of 1.3:1. All isolates were A2 mating type and formed spherical oogonia (mean diameter 28 ± 2 μm) with smooth walls and amphigynous antheridia in dual cultures with a reference isolate of the A1 mating type of P. nicotianae. BLAST analysis of the internal transcribed spacer (ITS) region of rDNA of a representative isolate from aeonium (IMI 398812, GenBank Accession No. HQ433333) amplified by PCR using the ITS6/ITS4 universal primers (1), revealed 99% similarity with the sequences of a reference isolate of P. nicotianae available in GenBank (Accession No. EU331089.1). Pathogenicity of isolate IMI 398812 was demonstrated by transplanting cuttings of A. arboreum into pots filled with a mixture of steam-sterilized sandy loam soil and inoculum (4% vol/vol) produced by growing the isolate for 20 days on wheat kernels. Ten plants were transplanted into 3-liter pots (two plants per pot) while 10 plants, transplanted into pots filled with a mixture of steam-sterilized soil and noninoculated kernels, were used as controls. Plants were kept in a greenhouse at 25 to 28°C and watered daily to field capacity. Thirty to forty days after the transplanting into infested soil, cuttings developed the same symptoms observed on plants with natural infections. Control plants remained symptomless. P. nicotianae was reisolated from symptomatic plants, thereby completing Koch's postulates. To our knowledge, this is the first report of P. nicotianae on an Aeonium species worldwide. The economic relevance of this disease is minor because aeoniums are not cultivated on a large scale. Moreover, the disease may be easily prevented by avoiding excess irrigation water since aeoniums need a well-drained soil or potting mix and do not tolerate soil waterlogging. References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) H. Masago et al. Phytopathology 67:425, 1977.

Root and Basal Stem Rot of Mandevillas Caused by Phytophthora spp. in Eastern Sicily

Approximately 150,000 potted mandevillas (Apocynaceae) are produced each year in the Etna District of eastern Sicily. Since 2004, leaf chlorosis, wilt, and sudden collapse of the entire plant associated with root and basal stem rot of 6- to 12-month-old potted mandevillas, including Mandevilla × amabilis 'Alice du Pont', M. splendens, and M. sanderi 'Alba', 'My Fair Lady', and 'Scarlet Pimpernel', have been observed in six nurseries. Incidence of affected plants varied from 5 to 40%. Four Phytophthora species were consistently isolated from rotted roots and stems on a selective medium (2). Pure cultures of the first species produced colonies with a camellia pattern on potato dextrose agar and grew between 10 and 37°C with an optimum of 27°C. On V8 juice agar they produced ellipsoid to obpyriform (length/breadth [l/b] 1.45:1), nonpapillate sporangia with internal proliferation, coralloid, spherical hyphal swellings and both terminal and intercalary chlamydospores. In dual cultures with A1 and A2 isolates of P. nicotianae, all isolates produced oogonia with amphyginous antheridia only with A2 isolates. Isolates of the second species formed petaloid colonies, had an optimum growth temperature of 25°C, and produced mono- and bipapillate, ovoid to limoniform sporangia (l/b 1.40:1); they did not produce gametangia. Isolates of the third species formed colonies with a slight petaloid pattern and grew between 2 and 30°C with an optimum of 25°C. Sporangia were obpyriform (l/b 1.48:1), nonpapillate, and proliferous. All isolates were A2 mating type. The isolates of the fourth species formed arachnoid colonies, grew between 8 and 38°C with an optimum of 30°C, and produced mono- and bipapillate, ellipsoid, and obpyriform (l/b 1.3:1) sporangia and apical chlamydospores. All isolates were A2 mating type. DNA was extracted from mycelium and amplified by PCR using the ITS 4/ITS 6 primers (1). Blast search of the rDNA-ITS sequence of isolate IMI 397618 (GenBank Accession No. GQ388261) of the first species showed 100% identity with the ITS sequence of an isolate of P. cinnamomi var. parvispora (EU748548). The sequences (GQ463703 and GQ463704) of isolates IMI 397471 and IMI 397472 of the second species showed 99% similarity with the sequences of a P. citrophthora isolate (EU0000631). The sequence of isolate IMI 397473 (GQ463702) of the third species showed 99% similarity with the sequence of a P. cryptogea isolate (AY659443.1), while the sequence of isolate IMI 397474 (GU723474) of the fourth species showed 99% similarity with the sequence of a P. nicotianae isolate (EU331089). The pathogenicity of individual isolates IMI 397618, IMI 397471, IMI 397472, IMI 397473, and IMI 397474 was tested on 3-month-old potted plants (10 plants per isolate) of mandevilla 'Alice du Pont' by applying 10 ml of a suspension (2 × 10⁴ zoospores/ml) to the root crown. Plants were maintained at 25°C and 95 to 100% relative humidity. All inoculated plants wilted after 4 weeks, while noninoculated control plants remained healthy. The four Phytophthora spp. were subsequently reisolated only from symptomatic plants. To our knowledge, this is the first report of P. cinnamomi var. parvispora in Italy and on mandevilla worldwide. In recent years, Phytophthora root and stem rot has become the most serious disease of potted mandevillas in Sicily. References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) H. Masago et al. Phytopathology 67:425, 1977.

First Report of a Decline and Wilt of Young Olive Trees Caused by Simultaneous Infections of Verticillium dahliae and Phytophthora palmivora in Sicily

In summer 2008, leaf chlorosis, defoliation, exceptional fruit set, twig dieback, and wilt were observed on 4-year-old olive (Olea europea L.) trees cv. Tonda Iblea in a drip-irrigated orchard in eastern Sicily. Rot of fine roots was associated with these symptoms and on ~15% of symptomatic trees rot extended to the crown and basal stem. Trees declined slowly or collapsed suddenly with withered leaves still attached. Incidence of affected trees was ~10%. A fungus identified as Verticillium dahliae Kleb. was isolated from the xylem of main roots and basal stem. An oomycete identified as Phytophthora palmivora (Butler) Butler was isolated from roots and basal trunk bark. Both pathogens were recovered from symptomatic trees with mean frequency of positive isolations per tree of 80 and 30% for V. dahliae and P. palmivora, respectively. To isolate V. dahliae, wood chips were surface disinfested in 0.5% NaOCl for 1 min and plated onto potato dextrose agar (PDA). The fungus was identified on the basis of microsclerotia, verticillate arrangement of phialides on conidiophores, and hyaline single-celled conidia. Ten monoconidial isolates were characterized by PCR using primer pairs INTND2f/INTND2r and DB19/espdef01 (3). Only 824-bp amplicons, diagnostic of the virulent, nondefoliating V. dahliae pathotype, were obtained. P. palmivora was isolated on selective medium (2) and pure cultures were obtained by single-hypha transfers. Colonies grew on PDA between 10 and 35°C (optimum at 27°C). Chlamydospores and elliptical to ovoid, papillate, caducous (mean pedicel length = 5 μm) sporangia (length/breadth ratio of 1.8) were produced on V8 juice agar. All isolates were paired with reference isolates of P. nicotianae and produced gametangia only with isolates of the A₂ mating type. PCR amplicons of a representative isolate generated using primers ITS 6 and ITS 4 (1) were sequenced and found to be identical to those of a reference isolate of P. palmivora (GenBank No. AY208126). Pathogenicity of V. dahliae (IMI 397476) and P. palmivora (IMI 397475) was tested on 6-month-old rooted cuttings of olive cv. Tonda Iblea. Ten cuttings were transplanted into pots with steam-sterilized soil and inoculum of P. palmivora (4% vol/vol) produced on wheat kernels. Ten olive cuttings were inoculated with V. dahliae by injecting the stem with 150 μl of a conidial suspension (10⁷ conidia ml^-1) and 10 cuttings were stem inoculated with V. dahliae and transplanted into soil infested with P. palmivora. Controls were 10 noninoculated cuttings transplanted into steam-sterilized soil. Pots were kept in a greenhouse (25 ± 3°C) for 4 months. No aerial symptoms were observed on cuttings transplanted into soil infested with P. palmivora. However, root dry weight was reduced by 40% in comparison with the controls. Cuttings inoculated solely with V. dahliae had a 15% reduction in height compared with the controls but only four cuttings wilted. All cuttings inoculated with P. palmivora and V. dahliae wilted, indicating a synergism between the two pathogens. Controls remained healthy. Each pathogen was reisolated solely from inoculated cuttings and both pathogens were reisolated from cuttings with double inoculations. A similar syndrome 'seca' (drying) was reported in Spain (4). References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) J. Mercado-Blanco et al. Plant Dis. 87:1487, 2003. (4) M. E. Sánchez-Hernández et al. Eur. J. Plant Pathol. 104:34, 1998.

Phytophthora taxon niederhauserii, a New Root and Crown Rot Pathogen of Banksia spp. in Italy

In the last 10 years, various species of Banksia (family Proteaceae) endemic to Australia have been introduced into Italy where cultivation as flower plants is expanding. In the spring of 2003, a decline associated with root and basal stem rot of 2- to 3-year-old plants of Banksia speciosa R. Br., B. baxteri R. Br., and B. prionotes Lindl. grown in the ground was observed in a commercial nursery in Liguria (northern Italy). Aboveground symptoms included leaf chlorosis and wilt. Plants collapsed within 1 to 2 weeks after the appearance of leaf symptoms. A Phytophthora species was consistently isolated from roots and basal stem on BNPRAH selective medium (3). On V₈ juice agar (V₈A), axenic cultures obtained by single hyphal transfers formed stellate to radiate colonies with aerial mycelium; on potato dextrose agar (PDA). the colonies showed stoloniform mycelium. Minimum and maximum growth temperatures on PDA and V₈A were between 5 and 10°C and 38 and 40°C, respectively, with the optimum at 30°C on PDA (mean radial growth rate of 10 isolates ranged between 9.3 and 10.2 mm per day) and 25 to 30°C on V₈A (14 mm per day). In saline solution and soil extract, all isolates produced catenulate hyphal swellings and ellipsoid, nonpapillate, persistent sporangia. Sporangia in saline solution varied from 47 to 70 × 30 to 44 μm (mean l/b ratio of 1.5). All isolates were A₁ mating type and produced oogonia with amphyginous antheridia when paired with A₂ mating type of P. drechsleri Tucker on V₈A plus β-sytosterol (3). The electrophoretic patterns of total mycelial proteins and two isozymes (esterase and malate dehydrogenase) (2) of all isolates from Banksia plants were identical, but distinct from the patterns of isolates of other Phytophthora species, including P. drechsleri, P. megasperma sensu stricto, and P. sojae. Internal transcribed spacer (ITS) regions of rDNA were amplified with primers ITS4/ITS6 and sequences of two isolates, IMI 393960 from B. speciosa and 466/03 from B. baxteri (GenBank Nos. FJ648808 and FJ648809), were 100% identical to sequences of isolates identified as Phytophthora taxon niederhauserii Z. G. Abad and J. A. Abad (GenBank Nos. AY550916, AM942765, and EU244850). Pathogenicity tests were performed on 1-year-old potted plants of B. speciosa with isolates IMI 393960 and 466/03. Twenty plants per each isolate were transplanted into 12-cm-diameter pots containing infested soil prepared by mixing steam-sterilized sandy loam soil with 1% of inoculum produced on autoclaved wheat kernels. Twenty control plants were grown in autoclaved soil mix. Plants were kept in the greenhouse with natural light at 25 ± 2°C and watered to field capacity weekly. All Banksia plants transplanted in infested soil showed symptoms of wilt, leaf chlorosis, and basal stem rot within 2 to 3 weeks. Noninoculated plants remained healthy. P. taxon niederhauserii was reisolated solely from inoculated plants. P. taxon niederhauserii has been reported recently from Banksia spp. in Australia (1), but to our knowledge this is the first report from Italy. P. taxon niederhauserii may represent a threat to the cultivation of many ornamentals including Cystus spp., English ivy, and laurel (4). References: (1) T. I. Burgess et al. Plant Dis. 93:215, 2009. (2) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (3) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (4) E. Moralejo et al. Plant Pathol, 58:100, 2009.

Callistemon citrinus and Cistus salvifolius, Two New Hosts of Phytophthora taxon niederhauserii in Italy

Bottlebrush (Callistemon citrinus (Curtis.) Skeels., Myrtaceae) and rock rose (Cistus salvifolius L., Cistaceae) are evergreen shrubs native to Australia and the Mediterranean Region, respectively. In the spring of 2003, approximately 2% of a nursery stock of 12-month-old potted plants of C. citrinus and 8% of a nursery stock of 12-month-old potted plants of Cistus salvifolius grown in the same nursery in Sicily, showed symptoms of leaf chlorosis, defoliation, and wilt associated with root and collar rot. A Phytophthora species was consistently isolated from roots and basal stems on BNPRAH selective medium (2). One isolate from rock rose (IMI 391708) and one from bottlebrush (IMI 391712) were characterized. On potato dextrose agar (PDA), the colonies showed stoloniform mycelium and irregular margins; on V8 juice agar (V8A), colonies were stellate to radiate. Minimum and maximum temperatures on PDA were 10 and 35°C, respectively, with the optimum at 30°C. Mean radial growth rate of isolates on this substrate was 9.9 and 11.3 mm/day, respectively. In saline solution (1), both isolates produced catenulate hyphal swellings and ellipsoid, nonpapillate, persistent sporangia with internal proliferations and dimensions of 52 to 70 × 30 to 42 μm and 51 to 85 × 39 to 45 μm. Mean l/b ratio of sporangia for both isolates was 1.8 ± 1. On V8A plus β-sytosterol, both isolates produced amphyginous antheridia and spherical oogonia in dual cultures with an A2 tester of P. drechsleri Tucker. Conversely, they did not produce gametangia with an A1 tester of P. cryptogea Pethybr., indicating they were A₁ mating type. The internal transcribed spacer (ITS)-rDNA sequences of rock rose and bottlebrush isolates showed 100% similarity with those of two reference isolates of P. taxon niederhauserii from GenBank (Accession Nos. FJ648808 and FJ648809). On the basis of the analysis of the DNA, the species isolated from bottlebrush and rock rose were identified as Phytophthora taxon niederhauserii. Pathogenicity tests were carried out on 6-month-old potted plants of C. salvifolius and C. citrinus (10 plants of each plant species for each isolate) transplanted into pots (12 cm in diameter) containing a mixture of 1:1 steam-sterilized, sandy loam soil (vol/vol) with 4% inoculum produced on autoclaved kernel seeds. Plants were maintained at 25 to 28°C and watered to soil saturation once a week. After 2 to 3 weeks, all inoculated plants developed symptoms identical to those observed on plants with natural infections. Ten control plants transplanted into pots containing noninfested soil remained healthy. P. taxon niederhauserii was reisolated solely from inoculated plants. To our knowledge, this is the first report of P. taxon niederhauserii on C. citrinus and C. salvifolius in Italy. This Phytophthora taxon has been reported recently on rock rose in Spain (3). References: (1) D. W. Chen and G. A. Zentmyer. Mycologia 62:397, 1970. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) E. Moralejo et al. Plant Pathol. 58:100, 2009.

First Report of Phytophthora tentaculata Causing Root and Stem Rot of Oregano in Italy

Oregano (Origanum vulgare L.; Lamiaceae) is cultivated for culinary and medicinal purposes and as an ornamental. In October of 2007, 1- to 2-year-old potted plants of oregano showed symptoms of decline associated with root and basal stem rot in a nursery in Liguria (northern Italy) that produces 1 million to 1.5 million potted aromatic plants per year. Aboveground symptoms included leaf russeting and chlorosis, wilt, defoliation and dieback of twigs, browning of the basal stem, and subsequent collapse of the entire plant. Approximately 80% of the plants died within 30 days after the appearance of the first symptoms on the canopy. Approximately 20% of a stock of 30,000 oregano plants was affected. Stocks of other aromatic species, such as mint, lavender, rosemary, and sage, appeared healthy. A Phytophthora species was consistently isolated from symptomatic stems and roots of oregano plants on BNPRAH selective medium (2). Ten pure cultures were obtained by single-hypha transfers, and the species was identified as Phytophthora tentaculata Kröber & Marwitz by morphological criteria and sequencing of the internal transcribed spacer (ITS) region of rDNA using the ITS 4 and ITS 6 universal primers for DNA amplification. Isolates from oregano formed stoloniferous colonies with arachnoid mycelium on potato dextrose agar and had a growth rate of 2 to 3 mm per day at 24°C with optimum, minimum, and maximum temperatures of 24, 8, and 34°C, respectively. Sporangia formed in soil extract solution and were papillate and spherical or ovoid to obpyriform with a length/breadth ratio of 1.3:1. Few sporangia were caducous and all had a short pedicel (<5 μm). Hyphal swellings and chlamydospores were produced in sterile distilled water and corn meal agar, respectively. All isolates were homothallic and produced globose terminal oogonia (mean diameter of 34 μm) with one or occasionally two paragynous, monoclinous, or diclinous antheridia. Amphigynous antheridia were also observed. The sequence of the ITS region of the rDNA (GenBank No. FJ872545) of an isolate from oregano (IMI 395782) showed 99% similarity with sequences of two reference isolates of P. tentaculata (Accession Nos. AF266775 and AY881001). To test for pathogenicity, the exposed root crowns of 10 6-month-old potted plants of oregano were drench inoculated with 10 ml of a suspension of 2 × 10⁴ zoospores/ml of isolate IMI 395782. Sterile water was pipetted onto the roots of 10 control plants. All plants were maintained in 100% humidity at 22 to 24°C in a greenhouse under natural light and watered once a week. Within 3 weeks after inoculation, all inoculated plants developed symptoms identical to those observed in the nursery and died within 30 to 40 days after the appearance of the first symptoms. Control plants remained healthy. P. tentaculata was reisolated solely from symptomatic plants. P. tentaculata has been reported previously on several herbaceous ornamental plants (1,3). However, to our knowledge, this is the first report of this species on O. vulgare. Root and basal stem rot caused by P. tentaculata is the most serious soilborne disease of oregano reported in Italy so far. References: (1) G. Cristinzio et al. Inf. Fitopatol. 2:28, 2006. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (3) H. Kröber and R. Marwitz. Z. Pflanzenkr. Pflanzenschutz 100:250, 1993.

Four Phytophthora Species Causing Foot and Root Rot of Apricot in Italy

In the summer of 2006, 1-year-old apricot (Prunus armeniaca L.) trees with leaf chlorosis, wilting, and defoliation associated with root and crown rot were observed in a nursery in Sicily (Italy). Of 3,000 plants, ~2% was affected. Four Phytophthora spp. (45, 25, 20, and 10% of the isolations of the first, second, third, and fourth species, respectively) were isolated from decayed roots and trunk bark on BNPRAH (3). Axenic cultures were obtained by single-hypha transfers. Isolates of the first species formed petaloid colonies on potato dextrose agar (PDA) and had an optimum growth temperature of 25°C. On V8 agar (VA), they produced persistent, papillate (often bipapillate), ovoid to limoniform sporangia (length/breadth ratio 1.4:1). They did not produce gametangia when paired with A1 and A2 isolates of Phytophthora nicotianae. The second species formed arachnoid colonies, had an optimum growth of 30°C, and produced uni- and bipapillate, ellipsoid, ovoid or pyriform sporangia (length/breadth ratio 1.3:1). All isolates were A2. The third species formed rosaceous colonies on PDA, had an optimum temperature of 28 to 30°C, and produced papillate (sometime bipapillate), ellipsoid or limoniform (length/breadth ratio 2:1), caducous sporangia with a tapered base and a long pedicel (as much as 150 μm). All isolates were A1 type. The fourth species formed petaloid-like colonies on PDA and had an optimum growth of 26 to 28°C. On VA, it produced papillate (sometimes bipapillate), ovoid (length/breadth ratio 1.3:1), and decidous sporangia with a short pedicel (<4 μm). The isolates were homothallic and produced oogonia (25 to 31 μm in diameter) with paragynous antheridia and aplerotic oospores. On the basis of morphological and cultural characters, the species were identified as P. citrophthora, P. nicotianae, P. tropicalis and P. cactorum. Identification was confirmed by the electrophoretic analysis of total mycelial proteins and four isozymes (acid and alkaline phosphatases, esterase, and malate dehydrogenase) on polyacrylamide gel (1). Analysis of internal transcribed spacer (ITS) regions of rDNA using the ITS 4 and ITS 6 primers for DNA amplification (2) revealed 99 to 100% similarity between apricot isolates of each species and reference isolates from GenBank (Nos. AF266785, AB367355, DQ118649, and AF266772). The ITS sequence of a P. citrophthora isolate from apricot (IMI 396200) was deposited in GenBank (No. FJ943417). In the summer of 2008, pathogenicity of apricot isolates IMI 396200 (P. citrophthora), IMI 396203 (P. nicotianae), IMI 396201 (P. tropicalis), and IMI 396202 (P. cactorum) was tested on 3-month-old apricot seedlings (10 plants for each isolate) that were transplanted into pots filled with soil prepared by mixing steam-sterilized sandy loam soil (4% vol/vol) with inoculum produced on autoclaved kernel seeds. Ten control seedlings were grown in autoclaved soil. Seedlings were maintained in a screenhouse and watered daily to field capacity. Within 40 days of the transplant, all inoculated seedlings showed leaf chlorosis, wilting, and root rot. Control seedlings remained healthy. All four Phytophthora spp. were reisolated solely from inoculated plants. To our knowledge, this is the first report of Phytophthora root and crown rot of apricot in Italy and of P. tropicalis on this host. References: (1) S. O. Cacciola et al. Plant Dis. 90:680, 2006. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) H. Masago et al. Phytopathology 67:425, 1977.

Blight Caused by Sclerotium rolfsii on Potted Ornamental Citrus in Sicily

Approximately 140,000 container-grown ornamental citrus plants are produced each year in the province of Catania (eastern Sicily). In the spring of 2006, a severe blight was observed in a commercial nursery in Catania on 2-month-old rooted cuttings of lemon (Citrus limon (L.) Burm.) and calamondin (× Citrofortunella mitis (Blanco) J. W. Ingram & H. E. Moore). Approximately 80% of the nursery stock of 2,000 cuttings was affected. Cuttings were grown in 7.5-cm² pots made with compressed peat and wood pulp at 28 to 30°C with 95 to 100% relative humidity on benches in a greenhouse, The pot mix was composed of peat, perlite, and soil (2:1:2). Cuttings showed a dark brown necrotic lesion at the base of the stem that extended upward, resulting in chlorosis and wilting of the leaves. An invasive, white, cottony mycelium with a fan-like pattern and numerous, small, brown spherical sclerotia (0.5 to 4.0 mm in diameter) developed on infected tissues, in the potting mix as well as on the pot wall. Herbaceous cuttings collapsed within 2 weeks while woody cuttings gradually died. Symptomatic basal stem sections were disinfected for 1 min in 1% NaOCl, rinsed in sterile water, and plated on acidified (pH 4.5) potato dextrose agar (PDA). Isolations consistently yielded a fungus whose morphological characters corresponded to Sclerotium rolfsii Sacc. On PDA, it produced a septate mycelium with clamp connections and numerous olive brown-to-clove brown sclerotia (1 to 3 mm in diameter). Pathogenicity of two S. rolfsii isolates (IMI 396204 and IMI 396205) from citrus was confirmed on 3-month-old lemon cuttings grown in 10-cm-diameter plastic pots filled with a sterilized mix of peat moss and vermiculite (3:1) (10 cuttings for each isolate). Each pot was inoculated with 15 sclerotia harvested from 6-week-old cultures on PDA and placed on the soil surface around the base of the cutting. Ten noninoculated cuttings served as the control. Cuttings were kept in a growth chamber at 28°C and relative humidity at >95%. All inoculated cuttings showed wilting, blight, and stem rot within 3 weeks after inoculation. White mycelium and sclerotia were produced on the stem base and soil surface. Noninoculated controls remained symptomless. S. rolfsii was reisolated from infected cuttings. The pathogenicity test was repeated once with calamondin cuttings and the results were similar. Blight caused by S. rolfsii is widespread in nurseries of ornamentals in Italy (1). However, to our knowledge, this is the first report of this disease on potted ornamental citrus. Probably high temperature and moisture during rooting were conducive to the disease. References: (1) A. Garibaldi et al. Malattie Delle Piante Ornamentali. Calderini Edagricole, Bologna, Italy, 2000.

First Report of Phytophthora spp. as Pathogens of Pandorea jasminoides in Italy

In the summer of 2005, approximately 5% of a nursery stock of 12-month-old potted plants of bower vine (Pandorea jasminoides (Lindl.) K. Schum.) in Sicily (Italy) showed wilt, leaf chlorosis, defoliation, root rot, and collapse of the entire plant. Three Phytophthora spp. (20, 50, and 30% of the isolations of the first, second, and third species, respectively) were isolated from rotted roots on BNPRAH selective medium (2). Single-hypha isolates of the first species formed petaloid colonies on potato dextrose agar (PDA) and had an optimum growth temperature of 25°C (9.3 mm/day); on V8 juice agar, they produced uni- and bipapillate, ovoid to limoniform sporangia with mean dimensions of 45 × 30 μm and a mean length/width (l/w) ratio of 1.4:1. They did not produce gametangia when paired with A₁ and A₂ isolates of Phytophthora nicotianae. The second species formed arachnoides colonies on PDA, had an optimum growth temperature of 30°C (6.9 mm/day) and produced sporangia that were uni- and bipapillate, ellipsoid, ovoid, or pyriform to spherical (dimensions 44 × 34 μm; l/w ratio 1.3:1). All isolates were A₂ mating type and produced amphyginous antheridia and spherical oogonia with smooth walls. The third species formed rosaceous colonies on PDA, had an optimum growth temperature of 28 to 30°C (11.9 mm/day), and produced uni- and bipapillate, ellipsoid or limoniform, caducous sporangia (dimensions 52 × 26 μm; l/w ratio 2.1:1) with a tapered base and a long pedicel (as much as 150 μm). All isolates were A₁ type and produced amphigynous antheridia and spherical oogonia with smooth walls. The three species were identified as P. citrophthora, P. nicotianae, and P. tropicalis, respectively. The electrophoretic analysis of the mycelial proteins and four isozymes (1) confirmed the identification. Blast analysis of the sequence of the internal transcribed spacer region of the rDNA of a P. tropicalis isolate from bower vine (GenBank Accession No. EU076731) showed 99% similarity with the sequence of a P. tropicalis isolate from Cuphea ignea (GenBank Accession No. DQ118649). The pathogenicity of three isolates from bower vine, IMI 395552 (P. citrophthora), IMI 395553 (P. nicotianae), and IMI 395346 (P. tropicalis), was tested on 3-month-old potted bower vine plants (10 plants for each isolate) by applying 10 ml of a suspension (2 × 10⁴ zoospores/ml) to the root crown. The plants were maintained at 24°C and 95 to 100% relative humidity. All inoculated plants wilted after 4 weeks. Noninoculated control plants remained healthy. The three Phytophthora spp. were reisolated from symptomatic plants. To our knowledge, this is the first report of Phytophthora root rot of bower vine in Italy. References: (1) S. O. Cacciola et al. Plant Dis. 90:680, 2006. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.

First Report of Armillaria Butt Rot Caused by Armillaria mellea on Phoenix canariensis in Italy

During 2006, in a garden in the Mount Etna Piedmont, eastern Sicily (Italy), a 40-year-old specimen of Canary Island date palm (Phoenix canariensis hort. ex Chabaud) with a trunk circumference at breast height of 220 cm showed a rotted lesion with a viscous, brown ooze at the stem base and root initials. The lesion extended to approximately one-third of the trunk circumference. Trunk excavation exposed a wet rot of internal tissues, a cream-colored mycelial mat, and a mushroom-like smell. Although the rot spread inward (approximately 25 cm deep) with decay of nonlignified ground tissues and blackening of wood fibers, the palm did not show symptoms on the canopy. Conversely, ferns, apricot, and cedar trees growing at the same site had died from Armillaria rot over the last 10 years (2). In late autumn, clumps of honey mushroom-like sphorophores with a prominent annulus encircling the stalk formed at the base of the trunk. The spore print of the basidiocarp was light cream. The morphology of 100 basidiospores was determined microscopically. The basidiospores were smooth, elliptical, hyaline, and measured 7 to 9.5 × 5 to 7 μm. The fungus was isolated from diseased tissues on selective benomyl-dichloran medium (3) and was transferred to 2% malt extract agar where it formed ribbon-shaped, fast-growing, and profusely branching rhizomorphs. Armillaria mellea (Vahl.) P. Kumm. was identified on the basis of cultural and morphological characteristics. Identification was confirmed by electrophoresis of mycelial proteins and isozymes in polyacrylamide and starch slab gels (1,2). The electrophoretic patterns of the isolate from P. canariensis were identical to those of reference isolates of A. mellea from grapevine and fern isolated previously at the same site (2). The pathogenicity of the A. mellea isolate from palm (A-palm5) was tested on 20 3-year-old potted seedlings of P. canariensis grown in a greenhouse at 24 ± 4°C. Seedlings were inoculated with wood pieces of holly oak (Quercus ilex L.) colonized by the fungus (two pieces for each seedling) (4). Ten noninoculated plants served as controls. After 12 months, mycelial fans colonizing the root initials, the base of the stem, and the leaf stalks were observed on 14 inoculated seedlings. Although only four infected seedlings showed decline symptoms, the fungus was reisolated from all inoculated plants. No infections were observed in control plants. To our knowledge, this is the first report of Armillaria butt rot on a palm in Europe. References: (1) M. Bragaloni et al. Eur. J. For. Pathol. 27:147, 1997. (2) S. Grasso et al. Plant Dis. 84:592, 2000. (3) T. C. Harrington et al. Armillaria. Page 81 in: Methods for Research on Soilborne Phytopathogenic Fungi. The American Phytopathological Society, St. Paul, MN, 1992. (4) R. Metaliaj et al. Phytopathol. Mediterr. 45:3, 2006.

First Report of Bud Rot of Canary Island Date Palm Caused by Phytophthora palmivora in Italy

Canary Island date palm (Phoenix canariensis hort. ex Chabaud) is planted as an ornamental in Mediterranean climatic regions of the world. From 2004 to 2006, withering of the spear leaf was observed on screenhouse-grown potted plants of this palm in Sicily (Italy). The first symptom was a dark brown rot that extended from the petiole base of the spear to the adjacent youngest leaves and killed the bud. Dissection of plants revealed a foul-smelling internal rot. After the bud died, external older leaves remained green for months. As much as 10% of plants in a single nursery were affected. A Phytophthora species was consistently isolated from symptomatic plants on BNPRAH selective medium (4). Single zoospore isolates were obtained from the colonies. The species isolated was identified as Phytophthora palmivora (E. J. Butler) E. J. Butler on the basis of morphological and cultural characteristics (3). On V8 juice agar, the isolates produced elliptical to ovoid, papillate sporangia (33 to 77 × 22 to 38 μm) with a mean length/breadth ratio of 1.8. Sporangia were caducous with a short pedicel (mean pedicel length = 5 μm) and had a conspicuous basal plug. All isolates were heterothallic and produced amphigynous antheridia, oogonia, and oospores when paired with reference isolates of P. nicotianae and P. palmivora of the A2 mating type. The oogonium wall was smooth. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total mycelial proteins and four isozymes (alkaline phosphatase, esterase, glucose-6-phosphate dehydrogenase, and malate dehydrogenase of the isolates) from Phoenix canariensis were identical to those of P. palmivora reference isolates, including four Italian ones, two from pittosporum and olive, respectively, and two (IMI 390579 and 390580) from Grevillea spp. Phoenix canariensis isolates were clearly distinct from those of other heterothallic papillate species including P. capsici, P. citrophthora, P. katsurae, P. nicotianae, and P. tropicalis. Pathogenicity of one isolate from Phoenix canariensis (IMI 395345) was tested on 10 2-year-old potted Canary Island date palm plants. An aqueous 10⁵ zoospores per ml suspension (200 μl) was pipetted onto unwounded petiole bases of the three youngest central leaves of each plant. Sterile water was pipetted onto 10 control plants. All plants were incubated in 100% humidity at 24°C for 48 h and maintained in a greenhouse at 20 to 28°C. Within 3 weeks after inoculation, inoculated plants developed symptoms identical to those observed on plants with natural infections. Control plants remained healthy. P. palmivora was reisolated from symptomatic plants. Phytophthora bud rot is a common palm disease worldwide and Phoenix canariensis is reported as a host (2). To our knowledge, this is the first report of Phytophthora bud rot on Phoenix canariensis in Italy. References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (2) M. L. Elliot et al., eds. Compendium of Ornamental Palm Diseases and Disorders. The American Phytopathological Society, St. Paul, MN, 2004. (3) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (4) H. Masago et al. Phytopathology, 67:425, 1977.

Blight of English Ivy (Hedera helix) Caused by Sclerotium rolfsii in Sicily

English ivy, Hedera helix L. (Araliaceae), an evergreen climbing vine is widely cultivated as an ornamental and foliage plant. In the summer of 2005, a severe blight of ivy plants trained as topiaries and grown in an open field was observed in a nursery near Giarre (eastern Sicily). Foliage of infected plants appeared lighter green and progressively turned bronze and withered. Eventually, the entire plant collapsed. Foliar symptoms were associated with basal stem and root rot. White, cottony mycelium and numerous sclerotia developed externally on the lower stem and on the soil around the affected plants. The disease was randomly distributed, affecting approximately 5% of plants in a stock of 1,500 English ivy plants. Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough) was consistently isolated from symptomatic basal stem tissues by disinfecting in 1% NaOCl and plating on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate. The isolated fungus was identified on the basis of morphological and cultural characteristics (2). On PDA, it produced a densely, floccose, white mycelium. Mycelium was septate with clamp connections at hyphal septa. Optimum growth temperature was 30 ± 2°C. Numerous small (0.5 to 1.9 mm in diameter) sclerotia developed on the colony surface; they were spherical, occasionally slightly ellipsoidal, quite uniform in size (modal value of the diameter 1.4 mm), with a smooth surface. The surface color of the sclerotia was initially white, turned to pinkish buff, then to olive-brown, and eventually to clove brown as sclerotia matured. Sclerotia were most numerous in the center as well as close to the edge of petri dishes. Pathogenicity of one isolate obtained from infected plants was confirmed by inoculating 10 1-year-old potted English ivy plants by placing mycelium-infested wheat kernels and sclerotia on the soil surface around the collar of each plant. Ten noninoculated plants served as control. Plants were held in a dew chamber for 48 h at 28°C and subsequently placed in a greenhouse where the temperature ranged between 25 and 31°C. Plants showed wilting within 3 weeks after inoculation. Fans of white mycelium and numerous sclerotia were produced on the basal stem of inoculated test plants. Noninoculated controls remained healthy. S. rolfsii was reisolated from infected plants to fulfill Koch's postulates. English ivy has been already reported as a host of S. rolfsii, the causative agent of southern blight in nurseries of ornamentals (1). However, to our knowledge, this is the first report of southern blight on English ivy in Italy. The disease may have been favored by warm summer temperatures and overwatering with a drip irrigation system. References: (1) A. R. Chase. Compendium of Ornamental Foliage Plant Diseases. The American Phytopathological Society, St. Paul, MN, 1992. (2) J. E. M. Mordue. Corticium rolfsii. No. 410 in: Description of Pathogenic Fungi and Bacteria. CMI. Kew, Surrey, UK, 1974.

First Report of Southern Blight Caused by Sclerotium rolfsii on Hemp (Cannabis sativa) in Sicily and Southern Italy

Hemp (Cannabis sativa L.), family Cannabaceae, is an annual herbaceous plant that is 1.5 to 4.0 m tall and native to the Caucasus Region, northern India, and Iran. It is cultivated in warm to temperate regions worldwide for its fiber, oil, and psychoactive substances. In Europe, commercial plantings have decreased from 52,872 ha in 1989 to 18,716 ha in 2005. Recently however, cultivation of hemp as a natural fiber species has been encouraged by European Union policy (2). During the summer of 2003, patches of dead plants were observed in test plots of 12 monoecious and dioecious hemp cultivars (Beniko, Epsylon 68, Felina 34, Ferimon, Fedora 17, Futura 75, Bialobrzeskie, Dioica 88, Fibranova, Tiborszallasi, Lovrin, and Carmagnola) in an experimental field near Catania (eastern Sicily) previously planted to artichoke (Cynara scolymus L.). Plots were irrigated with a drip irrigation system. Symptoms were first detected in July with day/night temperatures between 35 and 26°C. Infected plants showed a dark brown-to-tan discoloration of the stem near the soil line. As disease progressed, the rot extended down to the crown and taproot, foliage became yellow, and the entire plant eventually collapsed. An extensive white, cottony mycelium and numerous spherical tan-to-dark brown sclerotia (0.5 to 4.0 mm in diameter) developed externally on infected tissues and soil. As much as 60% of the plants were affected in a single plot. Monoecious cultivars that had been planted earlier escaped the disease. Isolations from diseased tissues were performed by plating symptomatic tissues previously disinfected for 1 min in 1% NaOCl and rinsed in sterile water on acidified potato dextrose agar (pH 4.5). Isolations consistently yielded a fungus whose characters corresponded to Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 120-day-old hemp plants grown in individual pots. Twenty plants for each of the above listed cultivars (10 plants for each isolate) were inoculated by applying toothpick tips (5 mm) colonized by S. rolfsii to the lower part of the stem. Ten noninoculated plants served as controls. Plants were kept in a greenhouse with temperatures between 26 and 32°C and 95% relative humidity. High soil moisture was maintained with frequent watering. All inoculated plants showed blight and basal stem rot after 2 weeks, irrespective of the cultivar. By the third week, plants began to dry up and mycelium and sclerotia developed on the crown. Noninoculated controls remained symptomless. S. rolfsii was reisolated from inoculated plants. Although S. rolfsii has been reported on hemp in India since the 1930s (3), to our knowledge, this is the first report of southern blight caused by this fungus on C. sativa in Sicily and southern Italy. Residues of artichoke, a very susceptible host of S. rolfsii (1), might have been the source of inoculum for this outbreak on hemp. Most likely, high summer temperatures and overirrigation exacerbated the disease severity. References: (1) C. Cariddi and R. Lops. La Difesa delle Piante 19(1):27, 1996. (2) S. L. Cosentino et al. Agroindustria 2:137, 2003. (3) G. P. Hector. Ann. Rep. Dep. Agric. Bengal 35, 1931.

Wilt and Collapse of Cuphea ignea Caused by Phytophthora tropicalis in Italy

The genus Cuphea (Lythraceae) includes approximately 250 species of annual, evergreen perennials and short shrubs native to Central and South America. During the springs of 2003 and 2004, 10% of the nursery stock of approximately 12,000 potted cigar-flowers (C. ignea A. DC) grown in a screenhouse at a commercial ornamental nursery near Piedimonte Etneo, Sicily, had symptoms of wilt, defoliation, and rapid collapse of the entire plant. These foliar symptoms were associated with a reduced root system, browning of the collar, and dark brown discolored roots. A Phytophthora species was consistently recovered by plating small pieces of rotted roots of symptomatic plants onto selective medium (3); pure cultures were obtained by single-hypha transfers. On potato dextrose-agar (PDA), cardinal temperatures for growth were 10 to 35°C and the optimum was 28 to 30°C. Sporangiophores were umbellate or in a close monoclasial sympodium and mean dimensions of sporangia were 52 × 26 mm, with a mean length/width ratio of 2:1. Sporangia produced on V8 juice agar (VJA) were ellipsoid, fusiform, or limoniform with a tapered base. They were papillate, occasionally bipapillate, caducous, with a long pedicel (as much as 150 μm). All isolates were mating type A1 determined by pairing with A2 reference isolates of P. palmivora (Butl.) Butl. and P. nicotianae Breda de Haan. Oogonia with amphigynous antheridia were formed on VJA after 10 to 15 days at 24°C in the dark. Occasionally, 10 of 15 isolates formed small chlamydospores on VJA. Electrophoretic patterns of total mycelial proteins and four isozymes (acid and alkaline phosphatase, esterase, and malate dehydrogenase) on polyacrylamide slab gels (3) of all Cuphea isolates were very similar to those of reference isolates of P. tropicalis M. Aragaki & J. Y. Uchida from Convolvulus cneorum L. (IMI 391714) and Rhamnus alaternus L., respectively. In addition, the Cuphea isolates were clearly distinct from reference isolates of other species including P. capsici Leon., P. citricola Sawada, P. citrophthora (R. E. Smith & E. H. Smith) Leon., P. nicotianae, and P. palmivora. On the basis of morphological cultural characters and the electrophoretic phenotype, the isolates were identified as P. tropicalis. Internal transcribed spacer (ITS) regions of rDNA sequences (2) confirmed the identification. Koch's postulates were fulfilled by testing three cigar-flower isolates, including isolate IMI 391709, on 10 6-month-old potted cuttings of Cuphea inoculated by applying a 10-ml zoospore suspension (2 × 10⁴ zoospores/ml) to the crowns, incubated for 24 h at 100% relative humidity, and maintained in the greenhouse at 20 to 24°C. After 10 days, crowns and stems were brown and all plants wilted within 20 days. Ten control plants treated with water remained healthy. P. tropicalis was reisolated from infected tissues. The test was repeated with similar results. In Europe, P. tropicalis has been reported on Cyclamen persicum Mill. in Germany (4) and C. cneorum and R. alaternus in Italy (1), indicating a broad host range and spreading in ornamental nurseries. References: (1) S. O. Cacciola et al. Boll. Acc. Gioenia Sci. Nat. 31:57, 1999. (2) S. O. Cacciola et al. For. Snow Landsc. Res. 76:387, 2001. (3) D. C. Erwin and O. K. Ribeiro. Pages 39-41, 138-139 in: Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul MN. 1996. (4) W. W. P. Gerlach and A. Schubert. Plant Dis. 85:334, 2001.

First Report of Brown Rot and Wilt of Fennel Caused by Phytophthora megasperma in Italy

Fennel (Foeniculum vulgare Mill. var. azoricum (Mill.) Thell.) in the Apiaceae family is native to southern Europe and southwestern Asia. It is an economically important crop in Italy that produces approximately 85% of all fennel worldwide. The main producing regions are Apulia, Campania, Latium, and Calabria. During the late winter of 2004 in the Crotone Province of the Calabria Region, following heavy rains, patches of fennel plants with symptoms of brown, soft rot of the bulb-like structure formed by the thickened leaf bases, development of yellow leaves, stunting, and wilting of the entire plant were observed in fields. A homothallic Phytophthora sp. was isolated consistently from the brownish tissues of the stout stems and leaf bases of symptomatic plants using a selective medium (3). Pure cultures were obtained by single hyphal tip transfers. On potato dextrose agar (PDA), the diameter of oospores varied from 28 to 42 μm (mean = 36.3 ± 0.4). Antheridia were primarily paragynous. Sporangia were not produced on solid media but were formed in sterile soil extract solution. They were nonpapillate, noncaducous, ovoid and obpyriform (25 to 45 × 35 to 60 μm), and internally proliferating. Optimum and maximum temperatures for radial growth of the colonies on PDA were 25 and 30°C, respectively. At 25°C, radial growth rate was approximately 6 mm per day. On the basis of morphological and cultural characteristics, the isolates were identified as Phytophthora megasperma Drechsler. Electrophoretic patterns of mycelial proteins and four isozymes (acid and alkaline phosphatase, esterase, and malate dehydrogenase) on polyacrylamide gels of the fennel isolates were identical to those of reference isolates of P. megasperma of the BHR (broad host range) group included in P. gonapodyides-P. megasperma Clade 6 (1,3), but distinct from those of the isolates of other nonpapillate species included in Waterhouse's taxonomic group VI. Internal transcribed spacer (ITS) regions of rDNA sequences (2) confirmed that fennel isolates belonged to P. megasperma BHR group. Pathogenicity of a fennel isolate from Calabria (IMI 391711) was confirmed by pouring a zoospore suspension at 2 × 10⁴ zoospores per ml on the soil of 10 3-month-old potted fennel plants. The soil of the inoculated and 10 control seedlings was flooded for 24 h. After 10 days, stems and leaf bases of the seedlings showed a brown rot. Chlorosis and wilting of all seedlings developed after 20 days. Controls inoculated with water did not develop any symptoms. The pathogen was reisolated from typical brown rot and tests were repeated with similar results. To our knowledge, this is the first report of P. megasperma causing disease on fennel. References: (1) S. O. Cacciola et al. For. Snow. Landsc. Res. 76:387, 2001. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (3) H. Masago et al. Phytopathology, 67:425, 1977.

Root and Basal Stem Rot of Scotch Broom Caused by Phytophthora citricola and P. drechsleri in Italy

Scotch broom (Cytisus scoparius (L.) Link, Fabaceae), an evergreen shrub native to Europe, is cultivated as a garden plant. In 2003 and 2004, potted plants with symptoms of leaf chlorosis, defoliation, and eventual wilt and associated with root and collar rot were observed in ornamental nurseries in Sicily. As much as 10% of plants were affected in a single nursery. Two species of Phytophthora were consistently isolated alone or together from the same pot with the selective medium of Masago et al. (2). Pure cultures were obtained by single-hypha transfers and the species were identified as P. citricola Sawada (approximately 40% of isolations) and P. drechsleri Tucker (60% of isolations) on the basis of morphological, cultural characters, and electrophoretic phenotype. The isolates of P. drechsleri grew between 10 and 37°C (optimum 27°C) on potato dextrose agar (PDA). The sporangia produced on V8 juice agar (V8A) were ellipsoid to obpyriform, nonpapillate, persistent with internal proliferation, and often forming in a sympodium. Sizes varied, 30 to 60 × 20 to 40 μm (length/width ratio between 1.4 and 2.2). The hyphal swellings were produced in aqueous culture. All isolates were A₁ mating type and formed plerotic oospores (mean diameter (ф) 25 μm) with amphigynous antheridia when paired with the A₂ reference isolates of P. cryptogea on V8A plus β-sitosterol. The aryl-esterase and malate dehydrogenase isozymes of scotch broom isolates on polyacrylamide slab gels (1) were identical to those of the authentic isolate CBS 292.35 of P. drechsleri and differed from reference cultures of other nonpapillate species. The cardinal temperatures of P. citricola isolates on PDA ranged from 2 to 30°C (optimum 25°C). In liquid culture, the isolates produced irregular-shaped, obovoid to obpyriform sporangia 20 to 70 × 21 to 44 μm that were noncaducous, semipapillate or with inconspicuous papilla, often with two apices. The isolates were homothallic and produced oospores (mean ф 22 μm) with paragynous antheridia. The electrophoretic phenotype of these isolates was identical to the phenotype of P. citricola reference isolates and very different from that of the reference isolates of other semipapillate species. The pathogenicity tests of the representative isolates of P. drechsleri (IMI 391710) and P. citricola (IMI 391715) were carried out in a screenhouse. Twenty 3-month-old scotch broom seedlings were transplanted into pots (12 cm ф) filled with soil infested with the inoculum produced on a mixture of vermiculite and autoclaved oat seeds. The plants were maintained at 20 to 28°C and watered to field capacity once a week. After 30 to 40 days, all inoculated plants showed symptoms of wilting and root rot. The 20 control plants transplanted into pots containing noninfested soil remained healthy. P. citricola and P. drechsleri were reisolated from infected tissues. To our knowledge, this is the first report of P. citricola and P. drechsleri on scotch broom. A root rot of scotch broom caused by P. megasperma has been reported in central Italy (3). References: (1) S. O. Cacciola et al. Plant Dis. 86:327, 2002. (2) D. C Erwin and O. K. Ribeiro. Pages 39-41 in: Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (3) A. M. Vettraino and A. Vannini. Plant Pathol. 53:417, 2003.

Root and Foot Rot of Lantana Caused by Phytophthora cryptogea

Lantana (Lantana camara L.) is an evergreen shrub in the Verbenaceae. In some countries, this plant has been declared a noxious weed. However, a number of sterile or near-sterile forms are cultivated as attractive flowered potted and garden plants. In early spring 2004, ≈4,000 potted, small trees of lantana grown in a screenhouse in a commercial nursery of ornamentals near Giarre, Sicily, showed symptoms of chlorosis, defoliation, and sudden collapse of the entire plant. These aboveground symptoms were associated with a reduced root system, rot of feeder roots, and brown discoloration of the base of the stem. A Phytophthora sp. was isolated consistently from roots and basal stems of symptomatic plants using the selective medium of Masago et al. (3). Cardinal temperatures for radial growth of pure cultures obtained by single hypha transfer were 2°C minimum, 25°C optimum, and 30 to 35°C maximum. Sporangia produced in the saline solution of Chen and Zentmyer (3) were obpyriform, persistent, and nonpapillate. All isolates were A1 mating type and differentiated oospores with amphigynous antheridia in dual cultures with A2 reference isolates of P. cryptogea Pethybr. & Laff. and P. drechsleri Tucker (3). Electrophoretic patterns of total mycelial proteins (3) of the isolates from lantana were very similar to those of reference isolates of P. cryptogea from different hosts, but clearly distinct from those of reference isolates of other species included in Waterhouse's taxonomic group VI (3). Indeed, isolates from lantana were identified as P. cryptogea on the basis of morphological and cultural characters as well as the electrophoretic phenotype. Sequences of internal transcribed spacer (ITS) regions of rDNA (1) confirmed the identification as P. cryptogea. Pathogenicity of a representative isolate from lantana (IMI 392045) was tested in a screenhouse by transplanting 20 6-month-old rooted cuttings of lantana in pots (12 cm in diameter) filled with infested soil; the soil was prepared by mixing steam-sterilized sandy loam soil at a concentration of 4% (vol/vol) with inoculum produced on a mixture of vermiculite and autoclaved oat seeds. Twenty control plants were transplanted in pots containing noninfested soil. The soil was saturated with water by plugging the pots' drainage holes for 48 h and watering. After 40 days, all plants except the controls showed symptoms of root and foot rot, and P. cryptogea was reisolated from infected tissues. To our knowledge, this is the first report of P. cryptogea on lantana. On this host and other species in the verbena family, only P. nicotianae van Breda de Haan (= P. parasitica Dastur) has been previously reported (2,3,4). A possible cause of the high incidence of this disease in the nursery was waterlogging due to heavy rain and excessive irrigation. References: (1) S. O. Cacciola et al. For. Snow Landsc. Res. 76:387, 2001. (2) M. L. Daughtrey et al. Compendium of Flowering Potted Plant Diseases. The American Phytopathological Society, St. Paul, MN, 1995. (3) D. C Erwin and O. K. Ribeiro. Pages 39-41, 84-95, 138-139 in: Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (4) K. H. Lamour et al. Plant Dis. 87:854, 2003.

First Report of Phytophthora palmivora on Grevillea spp. in Italy

The genus Grevillea (family Proteaceae) comprises over 300 species and is a popular and widely cultivated group of Australian plants. In the last 3 years, numerous potted grevilleas with symptoms of decline associated with a rot of feeder roots were found in ornamental nurseries in Sicily. Aboveground symptoms were reduced growth, yellowing of foliage, wilt, dieback, and death of the entire plant. The disease was observed on many commercial cultivars and was especially severe on G. alpina (mountain grevillea), G. juniperina (juniper-leaf grevillea), G. lavandulacea (lavender grevillea), and G. rosmarinifolia (rosemary grevillea) as well as the hybrid cultivars Clearview David (G. lavandulacea × rosmarinifolia) and Poorinda Rondeau (G. baueri × lavandulacea), while G. lanigera (woolly grevillea) cv. Mount Tamboritha and G. thelemanniana subsp. obtusifolia appeared resistant. A species of Phytophthora was consistently isolated from rotted roots of symptomatic plants using a selective medium (4), and pure cultures were obtained by single-hypha transfers. The species was identified as P. palmivora (E.I. Butler) E.I. Butler on the basis of morphological and cultural characters. On solid media, all isolates produced elliptical to ovoid, papillate sporangia with a mean length/width ratio of 1.8. Sporangia were caducous with a short pedicel (5 μm) and a conspicuous basal plug. All isolates were heterothallic (mating type A1) and produced oogonia and oospores only when paired with A2 mating type reference isolates of P. nicotianae and P. palmivora. Antheridia were amphyginous. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total soluble proteins and six isozymes (alkaline phosphatase, esterase, fumarase, NAD-glucose dehydrogenase, malate dehydrogenase, and superoxide dismutase) of isolates from grevillea were identical to those of a reference isolate of P. palmivora from Coronilla valentina subsp. glauca (2) but distinct from those of reference strains of eight other papillate species of Phytophthora included in Waterhouse's taxonomic group VI. Koch's postulates were fulfilled using 6-month-old rosemary grevillea plants that were transplanted into pots filled with soil that was artificially infested with chlamydospores (50 per gram of soil) produced in submerged cultures (3) by grevillea isolate IMI 390579. Plants were maintained in a glasshouse at 20 to 28°C and watered to field capacity once a week. One month after transplanting, infected plants showed decline symptoms similar to those of naturally infected plants. Control plants grown in pots containing noninfested soil remained healthy. P. palmivora was reisolated from roots of symptomatic plants. It appears that P. palmivora has become a widespread root pathogen in commercial ornamental nurseries in Italy (2). References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990.D. (2) S. O. Cacciola et al. Plant Dis. 86:327, 2002. (3) J. Y. Kadooka and W. H. Ko. Phytopathology 63:559, 1973. (4) H. Masago et al. Phytopathology 67:425, 1977.

A New Phytophthora sp. Causing a Basal Canker on Beech in Italy

In autumn 2001, bleeding cankers were observed on the basal portion of the trunk of a declining tree in a forest stand of European beech (Fagus sylvatica L.) in Latium (central Italy). A Phytophthora sp. was isolated consistently from infected trunk bark using whole apples as bait. Isolations were made from brown lesions that developed in the apple pulp around the inserted bark pieces. Pure cultures were obtained by using hyphal tip transfers. Colonies were stellate on V8 juice agar (V8A), uniform to slightly radiate on cornmeal agar, and cottony, without a distinct growth pattern on potato dextrose agar (PDA). On V8A, radial growth rates were 2.1, 4.8, and 4.5 mm/day at 10, 15, and 20°C, respectively. Colonies grew slowly at 5 and 25°C, but failed to grow at 30°C. On PDA, growth was 1.7 and 1.4 mm/day at 15 and 20°C, respectively. Catenulate hyphal swellings formed on solid and liquid media. Sporangia formed abundantly at 15°C, were ovoid to obpyriform, semipapillate, occasionally bipapillate, and had narrow exit pores (mean diameter = 5.4 μm). On V8A, pores were 40 to 50 μm in length and 25 to 40 μm in breadth. Isolates were homothallic with paragynous antheridia, oogonia were spherical with diameters from 32 to 35 μm, and oospores were plerotic with diameters from 20 to 30 μm. Electrophoretic banding patterns of mycelial proteins and isozymes (alkaline phospatase, esterase, glucose-6-phospate dehydrogenase, malate dehydrogenase, and superoxide dismutase) of beech isolates were distinct from those of reference isolates of semipapillate Phytophthora species, including P. citricola, P. hibernalis, P. ilicis (IMI 158964), P. psychrophila (CBS 803.95), and P. syringae from citrus fruits, whose identification had been confirmed on the basis of internal transcribed spacer (ITS)-restriction fragment length polymorphism (RFLP) patterns and sequences. Conversely, the electrophoretic phenotype and the ITS-RFLP pattern (and sequence) of the beech isolates were identical to those of a reference isolate (Ph24) from Quercus cerris, which was originally identified as P. syringae on the basis of morphological and cultural characters (1). However, the isolate Ph24 has been reexamined, and morphological and cultural characteristics as well as the ITS sequence would indicate that this isolate is a new species not yet formally described, for which the name P. pseudosyringae has been suggested (2). The pathogenicity of a beech isolate (IMI 390500) was compared to that of an Italian P. cambivora isolate from European chestnut by inoculating the stems of 16-month-old beech seedlings (10 replicates), which were placed at 18°C with a 12-h photoperiod. The beech isolate produced lesions averaging 2 cm long after 2 months, while those produced by the P. cambivora isolate averaged 3 cm. Control seedlings inoculated with sterile agar did not develop symptoms. The pathogen was reisolated from lesions to fulfil Koch's postulates. To our knowledge, this is the first report of this new Phytophthora sp. on beech in Italy. Conversely, the same species has been reported to be associated with decline of oak stands (1). References: (1) G. P. Barzanti et al. Phytopathol. Mediterr. 40:149, 2001. (2) T. Jung et al. Phytophthora pseudosyringae sp. nov., a new species causing root and collar rot of deciduous tree species in Europe. Mycol. Res. (In press).

First Report of Root and Crown Rot of Sage Caused by Phytophthora cryptogea in Italy

Sages are cultivated as aromatic and ornamental plants in Italy and represent the common name of certain species of Salvia and Phlomis (family Lamiaceae). In Sicily (southern Italy) during the summer of 2001, ≈40% of 1,400 2-year-old landscape plants of S. leucantha Cav. (Mexican bush sage or velvet sage) showed symptoms of stunting, chlorosis, and gradual dieback or sudden wilt, which are associated with root and crown rot. Plants were supplied by a commercial nursery, transplanted from pots in the spring, and irrigated using a trickle system. Phytophthora was isolated consistently from roots and basal stems of symptomatic plants on a BNPRAH medium (2). The species was identified as P. cryptogea Pethybr. & Laff., primarily on the basis of morphological and cultural characteristics. Five representative single-hypha isolates were characterized. On potato dextrose agar, they formed colonies with a slight petaloid pattern. Cardinal temperatures for mycelium growth were 2°C, minimum; 25°C, optimum; and 30 to 35°C, maximum. Hyphal swellings were abundant in aqueous culture. Sporangia were obpyriform, persistent, nonpapillate, and proliferous (2). All isolates were the A1 mating type and formed oogonia, amphigynous antheridia, and oospores in dual cultures with reference isolates of the A2 mating type of P. cryptogea and P. drechsleri. Identification was confirmed by electrophoresis of mycelium proteins on a polyacrylamide slab gel (1). Electrophoretic patterns of total soluble proteins from the sage isolates were identical or very similar to those from 10 reference isolates of P. cryptogea from various hosts, including isolate IMI 180615 (ex-type isolate). Conversely, the electrophoretic pattern of the isolates of P. cryptogea from sage was clearly distinct from those from reference isolates of other species included in Waterhouse's taxonomic group VI. Esterase (EC 3.1.1.2.) zymograms of the sage isolates corresponded to those of isolates of P. cryptogea included in electrophoretic group 2 (1). The pathogenicity of a representative isolate of P. cryptogea from sage was tested in the greenhouse using 4-month-old plants of Mexican bush sage. Inoculum was produced on a mixture of vermiculite and autoclaved oat seeds (4) and mixed with steam-sterilized sandy loam soil at a concentration of 4% (vol/vol). Plants were transplanted in pots (12 cm diameter) filled with infested soil; control plants were grown in pots containing noninfested soil. After transplanting, all pots were placed in shallow trays filled with water for 24 h to saturate the soil. All plants grown in infested soil showed extensive root necrosis and dieback ≈30 days after transplanting, and P. cryptogea was reisolated from roots of symptomatic plants. Control plants did not develop symptoms. Root and crown rot of sage caused by P. cryptogea has been reported previously in California (3). To our knowledge, this is the first report of P. cryptogea on sage in Italy. Root rot caused by P. cryptogea may be a potential problem for commercial cultivation of sage as no serious disease of this plant has been reported in Italy so far. References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (2) D. C Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. American Phytopathological Society, St. Paul MN. 1996. (3) S. T. Koike et al. Plant Dis. 81:959, 1997. (4) E. Sánchez-Hernández et al. Plant Dis. 85:411, 2001.

First Report of Botrytis Blight on Medinilla magnifica and Various Species of Mandevilla and Allamanda in Italy

Medinilla magnifica Lindl., Mandevilla splendens (Hook.) Woodson, the hybrid Mandevilla × amoena 'Alice du Pont' (pink allamanda), and various species of Allamanda, such as A. cathartica L. and A. blanchetii A. DC. (purple allamanda), are grown in Sicily as ornamentals. After a frost in early December 2001, a sudden wilt of container-grown cuttings of these tropical species was observed in a plastic-covered production greenhouse, with ≈30% of M. magnifica plants and 70% of Mandevilla and Allamanda plants affected. Medinilla plants (≈35 cm high) had been rooted in trays and transplanted individually in 30-cm-diameter pots. Allamanda (recently rooted cuttings) and Mandevilla (well-established) plants showed symptoms ranging from a dark brown rot at the base of stems to a tan-to-brown rot of stem midsection, respectively. Tissues surrounding lesions were water-soaked and covered by gray mycelium. On Allamanda and Mandevilla plants, lesions extended rapidly to lateral branches, and to the petiole and midrib of leaves that became chlorotic and wilted. As stems were girdled, infected plants collapsed, although the roots appeared healthy. Botrytis cinerea Pers.:Fr. was consistently isolated from infected stem pieces surface-disinfested with 1% NaOCl for 1 min and placed on potato dextrose agar (PDA, Oxoid). Morphology and size (6 to 8 × 8 to 12 μm, modal values 7 × 10 μm) of conidia produced on PDA matched those reported for B. cinerea (1). Dark, spherical, and irregularly shaped sclerotia (1 to 6 mm diameter, mean size 3.3 × 2.3 mm) were produced on PDA. Pathogenicity of a single-conidium isolate isolated from M. magnifica was confirmed using two inoculation methods. Twenty 3-month-old cuttings of M. magnifica and pink and purple allamanda were sprayed with a conidial suspension (10⁶ conidia per ml in a 2% glucose solution). A 2% glucose solution was sprayed on 20 control plants. Plants were sealed in transparent plastic bags for 7 days at 15 to 24°C. Typical symptoms developed only on stems of inoculated pink and purple allamanda cuttings 7 days after inoculation. B. cinerea was reisolated from affected tissues. In a separate test, stems of 10 6-month-old plants of M. magnifica and pink allamanda were inoculated by inserting a 3-mm plug taken from 10-day-old sporulating colonies growing on PDA on a superficial cut made with a sterile scalpel. The inoculated wounds were sealed with Parafilm. Ten wounded but noninoculated plants were used as controls. Plants were kept in high humidity at 10 to 20°C. After 10 days, stem necrosis, leaf chlorosis, and wilt were observed on inoculated pink allamanda plants. On inoculated M. magnifica plants, necrotic lesions were observed on stems (45 to 70 mm long and 10 to 18 mm wide) covered by gray mycelium, but the stem was not girdled. B. cinerea was reisolated from infected tissues of inoculated plants to complete Koch's postulates. No lesions developed on noninoculated control plants. To our knowledge, this is the first report from Italy of Botrytis blight on these species. The occurrence of frost may have predisposed these tropical species to infection by B. cinerea. Reference: (1) M. B. Ellis and J. M. Waller. No 431 in: Descriptions of Pathogenic Fungi and Bacteria, CMI, Kew, Surrey, UK, 1974.

Phytophthora palmivora a New Pathogen of Lavender in Italy

Root rot caused by Phytophthora nicotianae is considered the most serious disease of lavender in commercial cultivations in Italy. In summer 2001, in the Gela area (Sicily), ≈60% of 34,000 2-year-old landscape shrubs of English lavender (L. angustifolia) grown in a clay loam soil showed symptoms of dieback associated with root rot. Plants had been transplanted from pots in May and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from roots of symptomatic plants using potato dextrose agar (PDA) containing benomyl, nystatin, pentachloronitrobenzene, rifampicin, ampicillin, and hymexazol. The species was identified as P. palmivora on the basis of morphological and cultural characters. Ten representative single-zoospore isolates were characterized. On agar media, the isolates produced elliptical to ovoid, papillate sporangia, with a mean length/breadth ratio of 1.8. Sporangia, produced on sporangiophores forming simple sympodia (as many as 20 sporangia per sympodium), were caducous with a short pedicel (mean pedicel length = 5 μm) and a conspicuous basal plug. In addition to typical sporangia, all isolates produced sporocysts, i.e., subglobose, nonpapillate sporangia (2). The minimum temperature for mycelium growth on PDA was 10°C, the optimum was 27°C, and the maximum was 35°C. All isolates were A1 mating type. Antheridia were amphyginous. The identification was confirmed by electrophoresis of mycelial proteins on a polyacrylamide slab gel. Electrophoretic banding patterns of total soluble proteins and eight isozymes of the isolates from lavender were identical to those of a reference isolate of P. palmivora from olive (1). Conversely, the electrophoretic phenotype of the isolates from lavender was distinct from those of reference isolates of other species, including P. cactorum, P. capsici, P. citrophthora, P. nicotianae, and P. tropicalis. The pathogenicity of a representative isolate of P. palmivora from lavender was tested in the greenhouse using 6-month-old plants of English lavender, Rosea, a commercial cultivar very susceptible to root rot caused by P. nicotianae (3). Inoculum was produced on a mixture of vermiculite and autoclaved oat seeds (4) and mixed with soil (sand/lime/peat 1:1:1) at a concentration of 4% (vol/vol). Plants were transplanted to pots filled with infested soil. Control plants were grown in pots containing noninfested soil. After transplanting, all pots were flooded for 24 h by plugging the drain hole. Three months after transplanting all plants grown in pots containing infested soil showed extensive root necrosis and dieback symptoms. Control plants remained healthy. P. palmivora was recovered from roots of symptomatic plants. To our knowledge, this is the first report from Italy of P. palmivora on lavender. Root rot caused by P. palmivora may be a potential problem for commercial cultivation of lavender. References: (1) S. O. Cacciola et al. Plant Dis. 84:1153, 2000. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St Paul, MN, 1996. (3) G. Minuto et al. Inf. Fitopatol. 51:69, 2001. (4) E. Sánchez-Hernández et al. Plant Dis. 85:411, 2001.

First Report of Phytophthora palmivora on Coronilla valentina subsp. glauca in Italy

The genus Coronilla L. (family Fabaceae), which includes several species native to central and southern Europe, such as C. varia L. (axseed or crown-vetch), C. emerus (scorpion senna), and C. valentina L., is used in Italy as a landscape shrub or potted ornamental plant. During the summer of 2001, 80% of approximately 10,000 1-year-old plants of C. valentina subsp. glauca (L.) Batt. used to landscape an industrial area in the Caltanissetta Province (Sicily) showed symptoms of dieback associated with basal stem and root rot. Plants had been transplanted from pots in April and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from rotted roots and basal stems using BNPRAH selective medium (3). Pure cultures of this fungus were obtained by single-hypha transfers. Ten isolates, each originating from a single plant, were identified as P. palmivora (Butler) Butler on the basis of morphological and cultural characters as described by Erwin and Ribeiro (1). On solid media, including potato dextrose agar, cornmeal agar, and V8-juice agar, all the isolates produced elliptical to ovoid, papillate sporangia with a mean length/breadth ratio of 1.8. Sporangia were caducous with a short pedicel (mean pedicel length = 5 µm) and a conspicuous basal plug. Mating type was determined on V8 agar in dual culture with mating type A₁ and A₂ of reference isolates of P. nicotianae and P. palmivora. All isolates were heterothallic and produced oogonia and oospores only with reference isolates of the A₂ mating type. Antheridia were amphigynous. Electrophoresis of mycelial proteins on polyacrylamide slab gel confirmed that all isolates were pure cultures and belonged to the same species. Koch's postulates were fulfilled using 6-month-old C. valentina subsp. glauca plants that were transplanted into pots filled with soil artificially inoculated with chlamydospores (50 chlamydospores per gram of soil) produced in submerged axenic cultures (2). The plants were maintained in a glasshouse at temperatures ranging from 18 to 28°C, and the pots were watered to field capacity once a week. One month after transplanting, 70% of plants showed dieback symptoms, while control plants, which were grown in pots containing noninoculated soil, remained healthy. The pathogen was reisolated from roots and basal stems of symptomatic plants. These results demonstrate that P. palmivora is the causal agent of dieback of C. valentina subsp. glauca plants. High temperatures in summer and waterlogging of soil due to excess irrigation water could have enhanced disease development. To our knowledge, this is the first report of P. palmivora on a species of Coronilla. P. palmivora is an exotic pathogen, but it is becoming widespread in Italy, where it has been reported from various regions on different hosts, including cyclamen, English ivy, palms, Pittosporum, and olive. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St Paul, MN, 1996. (2) J. Y Kadooka and W. H. Ko. Phytopathology 63:559, 1973. (3) H. Masago et al. Phytopathology 67:425, 1977.

First Report of Phytophthora citrophthora Causing Fruit Brown Rot of Feijoa in Italy

Feijoa (Feijoa sellowiana) is native to South America. In the early 20th Century it was introduced into Sicily (southern Italy), where it is grown as an ornamental plant and for its fruits. In 1985 a Phytophthora brown rot of feijoa fruits was reported in the province of Syracuse (eastern Sicily) (2). Several species of Phytophthora, including P. citricola, P. citrophthora, and P. nicotianae, were recovered from soil samples taken from trees with infected fruits. These species were experimentally inoculated on detached feijoa fruits and all incited symptoms of brown rot. However, only P. citricola was isolated from naturally infected fruits. In early autumn 1999, an outbreak of Phytophthora brown rot of feijoa fruits was observed in the Syracuse province, in the same site where the disease had been first recorded. P. citricola (95% of the isolates) and P. citrophthora (5% of the isolates) were recovered from symptomatic fruits. The species were identified on the basis of morphological and cultural characters according to Erwin and Ribeiro (1). The P. citricola isolates formed colonies with a distinctive chrysanthemum pattern on potato-dextrose agar (PDA), had an optimum temperature for radial growth of 25°C, and were homothallic with paragynous antheridia and spherical oogonia (mean diameter of oogonia= 20 μm). Sporangia, which were produced only in water or saline solution, were semi-papillate (often with two apices) and variable in shape. The P. citrophthora isolates formed petaloid colonies on PDA, had an optimum temperature of 25°C, and produced noncaducous, papillate (frequently bipapillate), ovoid to limoniform sporangia. They did not produce gametangia. The identification of both species was confirmed by the electrophoresis of mycelial proteins on polyacrylamide slab gel. The electrophoretic patterns of total proteins and four isozymes (alkaline phosphatase, esterase, malate dehydrogenase, and superoxide dismutase) of the P. citricola and P. citrophthora isolates from feijoa were identical to those of reference isolates of these two species from various other hosts. Conversely, they were clearly distinct from the electrophoretic patterns of reference isolates of P. cactorum, P. capsici, P. nicotianae, and P. palmivora. The random amplified polymorphic DNA patterns of the P. citrophthora isolates from feijoa obtained by polymerase chain reaction (RAPD-PCR) were compared with those of reference isolates of other species of Phytophthora and those of P. citrophthora isolates obtained from citrus trees with symptoms of trunk gummosis and root rot, grown in the immediate vicinity of feijoa trees. DNA was extracted and analyzed following previously described procedures, using 16 decamer primers (3). The RAPD-PCR patterns of the P. citrophthora isolates from feijoa were identical to those of the isolates from citrus but were distinct from those of reference isolates of the other species of Phytophthora, suggesting that inoculum of P. citrophthora may have originated from infected citrus trees. P. citricola is known as a causal agent of fruit brown rot of feijoa and guava (Psidium guajava), a closely related species (1). Conversely, this is the first report of natural infections of P. citrophthora on feijoa fruits. References: (1) D. C. Erwin and O. K. Ribeiro, 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN. (2) G. Magnano di San Lio and R. Tuttobene. Inf. Fitopatol. 85:43, 1985. (3) Q. Migheli et al. Eur. J. Plant Pathol. 104:49, 1998.

Collar and Root Rot of Olive Trees Caused by Phytophthora megasperma in Sicily

Olive (Olea europea L.) is grown on about 154,000 ha in Sicily (southern Italy). In the summer of 1999, a few 3-year-old olive trees with decline symptoms were observed in a recently planted commercial orchard in the Enna province (Sicily). The trees were propagated on wild olive (O. europea L. var. sylvestris Brot.) rootstock. Aerial symptoms, consisting of leaf chlorosis, wilting, defoliation, and twig dieback followed in most cases by plant death, were associated with root rot and basal stem cankers. A Phytophthora sp. was consistently isolated from rotted rootlets and trunk cankers using the BNPRAH (benomyl, nystatin, pentachloronitrobenzene, rifampicin, ampicillin, and hymexazol) selective medium. Pure cultures were obtained by single-hypha transfers. The species isolated from symptomatic olive trees was identified as P. megasperma Drechsler on the basis of morphological and cultural characteristics. All isolates were homothallic, with paragynous antheridia. The diameter of oospores varied from 28 to 42 μm (mean ± SE = 36.3 ± 0.4) when they were produced on potato-dextrose agar (PDA) and from 30 to 43 μm (mean ± SE = 37.8 ± 0.4) when they were produced in saline solution. Sporangia were non-papillate. Optimum and maximum temperatures for radial growth of the colonies on PDA were 25 and 30°C, respectively. At 25°C, radial growth rate was about 6 mm per day. The identification was confirmed by the electrophoresis of mycelial proteins on a polyacrylamide slab gel. The electrophoretic banding patterns of total soluble proteins and three isozymes (esterase, fumarase, and malate dehydrogenase) of the isolate from olive were identical to those of two isolates of P. megasperma obtained from cherry and from carrot in Italy and characterized previously (1). Conversely, they were clearly distinct from the electrophoretic patterns of four isolates of P. megasperma var. sojae Hildebr. from soybean (= P. sojae Kauf. & Ger.), from those of three isolates from asparagus tentatively identified as P. megasperma sensu lato (1) and from those of reference isolates of various species producing non-papillate sporangia, including P. cambivora (Petri) Buisman, P. cinnamomi Rands, P. cryptogea Pethybr. & Laff., P. drechsleri Tucker, and P. erythroseptica Pethybr. Pathogenicity of the isolate from olive was tested in the greenhouse at 18 to 25°C using 18-month-old rooted cuttings of olive cv. Biancolilla. Cuttings were inoculated on the lower stem by inserting a 3-mm plug taken from actively growing colonies on PDA into an incision made with a sterile scalpel. The wound was sealed with waterproof tape. Agar plugs with no mycelium were placed into the stem of cuttings used as a control. The bark was stripped and lesion areas were traced and measured 60 days after inoculation. The isolate from olive produced a brown necrotic lesion (mean size = 500 mm²) around the inoculation wound and was reisolated from the lesion. Conversely, the wound healed up on control plants. P. megasperma has previously been recognized as a pathogen of olive in Greece and Spain (3). However, this is the first report of P. megasperma causing root and collar rot of olive in Italy. References: (1) S. O. Cacciola et al. Inf. Fitopatol. 46:33, 1996. (2) D. C. Erwin and O. K. Ribeiro, 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. (3) M. E. Sánchez-Hernádez et al. Plant Dis. 81:1216, 1997.

First Report of Phytophthora palmivora as a Pathogen of Olive in Italy

Olive (Olea europea L.) is an economically important crop in Italy and is planted on about 1 million ha. The Apulia, Calabria, and Sicily regions of Southern Italy account for about 70% of the production. Many new plantations have been established during the last 10 years. In summer 1999, 1- to 2-year-old olive trees (cv. Carolea) with decline symptoms were observed in new plantations in Catanzaro Province (Calabria). The symptoms associated with the root rot were leaf chlorosis, defoliation, wilting, twig dieback, and eventual plant collapse. In some cases, more than 40% of the trees were affected. A Phytophthora sp. was isolated consistently from rotted rootlets of diseased trees using a selective medium (2). Single-zoospore isolates were obtained from the colonies. The species isolated from olive roots was identified as P. palmivora (E. Butler) E. Butler on the basis of morphological and cultural characters according to Erwin and Ribeiro (1). All isolates produced papillate sporangia, which were elliptical to ovoid, caducous (mean pedicel length = 5 µm), with a length-breadth ratio of 1.8. In addition, some isolates produced subglobose, non-papillate sporangia with a length-breadth ratio ranging from 1.2 to 1.5. Electrophoresis of mycelial proteins on polyacrylamide gels confirmed that all isolates were pure cultures and that they all belonged to the same species. The electrophoretic banding patterns of total soluble mycelial proteins and eight isozymes (alkaline phosphatase, esterase, fumarase, NAD-glucose dehydrogenase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, and superoxide dismutase) of all olive isolates were identical to those of two strains of P. palmivora from parlor palm and from pittosporum. Conversely, they were clearly distinct from the electrophoretic banding patterns of reference isolates of P. cactorum (Lebert & Cohn) Schroter, P. capsici Leonian, P. citrophthora (R. E. Sm. & E. H. Sm.) Leonian, and P. nicotianae van Breda de Haan. All isolates of P. palmivora from olive were of the A1 mating type. The pathogenicity of four P. palmivora isolates from olive, two producing only typical and two producing both types of sporangia, was tested in the greenhouse at 18 to 25°C, using 20 1-year-old rooted cuttings of olive cv. Carolea for each isolate. Twenty noninoculated cuttings were used as a control. The inoculum for pathogenicity tests was produced on autoclaved rice grains moistened with V-8 juice. Cuttings were transplanted to pots filled with soil infested with inoculum at 2% (wt/vol). Control plants were grown in pots containing a mixture of soil and 2% autoclaved rice. After transplanting, all pots were flooded once a week for 24 h by plugging the drain hole of the pot. One month after planting, all the plants in infested soil had died and no difference in virulence was observed among the isolates. Control plants remained healthy. P. palmivora was reisolated from the roots of symptomatic plants. Pathogenicity tests were repeated twice with similar results. In a survey of nurseries in Southern Italy, P. palmivora was recorded frequently from roots of young olive trees suggesting that infections originated from nurseries. This is the first report from Italy of P. palmivora on olive. This species has been described recently as a pathogen of olive in Spain (3). References: (1) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. American Phytopathological Society. St. Paul, MN. (2) H. Masago et al. Phytopathology 67:25, 1977. (3) M. E. Sanchez Hernandez et al. Eur. J. Plant Pathol. 104:347, 1998.

First Report of Armillaria mellea on a Fern from Italy

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy. References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.

A Foliar Disease of European Hackberry Endemic in Sicily

European hackberry (Celtis australis L.; Ulmaceae), a semideciduous tree or shrub that produces small edible berries was originally grown in Italy to produce charcoal and timber and was particularly suitable for making whipstocks, carriage wheel spokes, and hoe handles. European hackberry is currently used for reforestation and as shade trees in parks and roadside plantings. Recently, a foliar disease caused by the dematiaceous hyphomycetous fungus Sirosporium celtidis (Biv.-Bern. ex Sprengel) M.B. Ellis on hackberry saplings in a nursery was observed in the Piedmont Region (northern Italy) by Giannetti et al. (2), who referred to it as a rare disease. However, during a survey in the nature reserve of the Anapo River Valley, in the Sicily Region (southern Italy), where European hackberry and a closely related species (C. tournefortii Lam.) grow naturally, most hackberry plants were found to be infected by S. celtidis, with variable intensity. During autumn, symptoms appeared on lower leaf surfaces as reddish brown to dark black-brown subcircular velvety spots (up to 10 to 15 mm wide) surrounded by narrow paler margins that were evenly distributed over the leaf surface and later confluent. Nonspecific symptoms on upper leaf surfaces were visible only in advanced stages and consisted of necrotic areas, usually apical or marginal, that were at first red-brown and later turned gray. A few trees were prematurely defoliated. Usually, however, severely affected leaves were necrotic, withered, and curled but remained attached. Spots on lower leaf surfaces were covered by mycelium, conidiophores, and conidia that corresponded to the description of S. celtidis published by Ellis (1). Conidia were straight, flexuous, occasionally markedly curved or coiled, cylindrical or obclavate, smooth, wrinkled or verrucose, subhyaline to golden or reddish brown, typically multicellular with 1 to 32 transverse septa, and occasionally had longitudinal or oblique septa that were often constricted, more than 100 μm long and up to 5 to 8 μm thick, with an inconspicuous scar at the base. From 1997 to 1999, infection by S. celtidis in the Anapo River Valley occurred each year, probably favored by the moist environment. S. celtidis, first described in Sicily as early as 1815 (1), has been recorded on various hackberry species in many countries, including the United States (3). Apparently this pathogen is of little economic and ecological significance in natural ecosystems; however, the fungus could become a serious problem in nurseries (2). References: (1) M. B. Ellis. 1963. Mycological Papers, No. 87. Commonw. Mycol. Inst. Kew, England. (2) G. Giannetti et al. Inform. Fitopatol. 49:39, 1999. (3) D. H. Linder. Ann. Mo. Bot. Garden 18:31, 1931.

Race 1,2y of Fusarium oxysporum f. sp. melonis on Muskmelon in Sicily

Muskmelon (Cucumis melo L.) is very important economically to agriculture in Italy. The Sicily area accounts for ≈40% of the total muskmelon production. Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (Leach & Currence) W.C. Snyder & H.N. Hans. is the most prevalent and damaging disease of muskmelon in Sicily. Use of cultivars with major resistance genes, Fom 1 and Fom 2, is the most effective control measure for combating the disease. During March 1999, severe infections of Fusarium wilt were noted in a commercial muskmelon crop, cv. Firmo F1, grown in plastic tunnels in Syracuse Province (eastern Sicily). The muskmelon seedlings had been transplanted into the tunnels during January 20 days after soil fumigation with methyl bromide. Firmo F1 possesses both Fom 1 and Fom 2 genes. Of 18,000 Firmo F1 plants, ≈6,500 showed symptoms consisting of stunting, vein clearing; leaf yellowing, wilting, and dying; brown necrotic streak; and gummy exudates on the basal portion of vines. A pinkish white mold developed on dead tissues when infected plants were kept at high relative humidity. The pathogenicity of both a single-conidium isolate of F. oxysporum f. sp. melonis from a symptomatic Firmo F1 plant and two isolates of races 0 and 1, recovered previously from other cultivars in Sicily and used as references, was tested with three differential muskmelon cultivars, Charentais T, Doublon, and CM 17187 (1), as well as three commercial cultivars, Ramon, Cassella, and Geamar (possessing Fom 1, Fom 2, and both Fom 1 and Fom 2 resistance genes, respectively). Muskmelon seedlings were inoculated by the root-dip method (3), using a suspension of 5 × 10⁵ conidia per ml. Inoculated seedlings were transplanted to plastic pots filled with sterilized soil and placed in a greenhouse (25 to 30°C). Symptoms were scored 7 to 10 days after inoculation. The isolate from Firmo F1 was pathogenic to all cultivars tested, the race 0 isolate was pathogenic only to cv. Charentais T, and the race 1 isolate was pathogenic only to cvs. Charentais T, Doublon, and Ramon. F. oxysporum was reisolated from symptomatic plants. Based on its pathogenicity and symptomology, the isolate from Firmo F1 was classified as race 1,2y (yellows), according to the nomenclature proposed by Risser et al. (1). Race 1,2 poses a serious threat to muskmelon production in Sicily, because all currently used cultivars are susceptible to the race, and other control measures, such as preplant soil fumigation with methyl bromide and solarization, are not as effective as use of resistant cultivars. Further study is needed to establish which is the prevalent race of F. oxysporum f. sp. melonis in Sicily. This report confirms that race 1,2 occurs in all major muskmelon-production areas in Italy (2). References: (1) G. Risser et al. Phytopathology 66:1105, 1976. (2) G. Tamietti et al. Petria 4:103, 1994. (3) F. L. Wellman. Phytopathology 29:945, 1939.

Outbreak of a Leaf Disease Caused by Pseudocercospora ceratoniae on Carob in Sicily

Carob (Ceratonia siliqua L.), an evergreen tree typical of the Mediterranean flora, has been grown in Sicily (Italy) from time immemorial for its fruits, used mainly as food for cattle and horses as well as for industrial production of alcohol. Although the economic importance of carob as a commercial crop has declined over the last decades, carob trees still are a characteristic aspect of the landscape in southeastern Sicily. In early April 1998, a severe outbreak of a foliar disease was noted on carob trees in the Ragusa province. Symptoms initially consisted of small (2 to 3 mm wide) dark brown, vein-limited spots, visible on both sides of the leaf and, later in the season, surrounded by a pale halo. In a humid atmosphere, spots scattered over the leaf blade but usually were most numerous along the midrib, enlarged, and coalesced, forming large blotches. Severely affected leaflets dropped, leaving the petiole attached to the tree. As a result, the trees appeared defoliated. Severely defoliated trees did not produce fruits. The causal agent of this disease was identified as Pseudocercospora ceratoniae (Pat. & Trab.) Deighton (1), an hyphomycetous fungus reported previously as a pathogen of carob under the name Cercospora ceratoniae Pat. & Trab. (3). On carob leaflets, P. ceratoniae formed grayish caespituli, confined to the lower surface of the necrotic spots. Caespituli consisted of dense fascicles of conidiophores (up to more than 50 conidiophores per fascicle) emerging through the stomata. Conidiophores were simple, slightly ampulliform, and geniculate at the conidial scars, which were conspicuous and unthickened. Old scars often were situated laterally on a short denticle. Conidia, borne singly as terminal blastospores and varying considerably in length, were pluriseptate, filiform, substraight or slightly curved, frequently slightly obclavate, with an obtuse apex and a short constriction at the base toward the truncate, unthickened hilum. Conidia from pure cultures of the fungus grown on water agar under black light were suspended in water and sprayed onto pot-grown carob plants. Inoculated plants were kept in a moist chamber for 48 h and subsequently transferred to the greenhouse. After 12 to 14 days leaf spots similar to those observed on naturally infected trees developed on inoculated plants and the pathogen was reisolated. Control plants sprayed with distilled water remained symptomless. C. ceratoniae had been recorded previously on carob in various Mediterranean countries, including Italy (2), but since has attracted little attention, being regarded as a sporadically occurring pathogen. Both mild temperatures during the winter and exceptionally frequent and persistent rain during the spring may have favored the epidemic outbreak of the disease caused by this fungus. References: (1) F. C. Deighton. 1976. Mycol. Pap. No. 140. Commonw. Mycol. Inst., Kew, England. (2) R. Parisi. Boll. Orto Bot. R. Univ. Napoli 10:155, 1932. (3) L. Roger. 1953. Phytopathologie des Pays Chauds. Vol. 2. P. Lechevalier, Paris.

Insensitivity to Metalaxyl Among Isolates of Phytophthora capsici Causing Root and Crown Rot of Pepper in Southern Italy

Pepper (Capsicum annuum L.) has become an economically important crop in the coastal provinces of Catanzaro and Vibo Valentia, in Calabria (southern Italy). An old local selection Riggitano, very susceptible to root and crown rot caused by Phytophthora capsici Leonian, is the prevalent cultivar in this area. Although repeated applications of metalaxyl are used as a soil drench, severe outbreaks occur each year on greenhouse crops. To examine metalaxyl resistance in P. capsici, 60 single-hypha isolates of P. capsici were tested in vitro for their level of sensitivity to metalaxyl. The isolates were collected from 1992 to 1997, during epidemic outbreaks of root and crown rot, from two commercial greenhouse pepper crops, near Vibo Valentia and Lametia Terme (Catanzaro). Fungicide sensitivity was determined by plating mycelial plugs onto potato dextrose agar (PDA) amended with metalaxyl. The fungicide was added to PDA after autoclaving, at final concentrations of 0.1, 1, 5, 10, 50, 100, and 200 μg/ml a.i. The percentage of inhibition of radial growth on metalaxyl-amended medium compared with the growth on unamended medium was determined after 6 days of incubation in the dark at 25°C. Three replicate petri dishes were used per treatment and each test was performed twice. The isolates were paired in culture on V8 agar with isolates of P. capsici of known mating type and all proved to be A2 mating type. Significant variation was observed among the isolates tested in responce to metalaxyl. The ED₅₀ values for in vitro inhibition of mycelial growth by metalaxyl ranged from 1 to 11 μg/ml, whereas an ED ₅₀ value of 0.1 μg/ml had been reported for a wild-type isolate of P. capsici obtained from pepper in northern Italy (3). The variation observed among the isolates from Calabria appeared unrelated to both the geographical origin and the year of isolation. The isolates from Calabria were inhibited by between 1 and 12% at 0.1 μg/ml and by between 7 and 27% at 1 μg/ml, proving to be less sensitive to metalaxyl than isolates from Capsicum spp. originating from Central America, tested by other authors (1). According to the criterion used in a recent screening for sensitivity to metalaxyl (2), 19% of the isolates from Calabria should be considered sensitive, as they were inhibited by more than 60% at 5 μg/ml, while all the others were intermediate, as they were inhibited less than 60% at 5 μg/ml but more than 60% at 100 μg/ml. On the basis of this preliminary screening, we report the presence of insensitivity to metalaxyl in field isolates of P. capsici in southern Italy. Although no isolate tested appeared highly resistant to metalaxyl, the presence of a high proportion of isolates with an intermediate level of resistance should be a reason for the growers to use metalaxyl more cautiously to control root and collar rot. References: (1) M. D. Coffey and L. A. Bower. Phytopathology 74:502, 1984. (2) G. Parra and J. Ristaino. Plant Dis. 82:711, 1998. (3) M. L. Romano and A. Garibaldi. La difesa delle piante 3:153, 1984.

First Report of Root Rot Caused by Phytophthora cinnamomi on Avocado in Italy

Root rot caused by Phytophthora cinnamomi Rands is generally recognized to be the most important disease of avocado (Persea americana Miller) wherever this tropical fruit tree is grown (3). The disease was first found in Italy in the spring of 1998. Eight-year-old trees, with symptoms ranging from initial to severe, were observed in an experimental field near Rocca di Caprileone, in Sicily. Few trees showed symptoms of both root rot and collar rot. Infected trees were of 13 commercial cultivars. Trees were grafted on two different rootstocks: Hass seedlings and G6 seedlings. G6 is a selection reported to have some field resistance to P. cinnamomi infections (2). However, no correlation was observed between symptom severity and rootstock. P. cinnamomi was isolated on BNPRAH selective medium (4) from trunk bark, feeder roots, and rhizosphere soil of diseased trees, and from roots of symptomless trees. The isolates, identified primarily on the basis of morphological and cultural characteristics, formed rosaceous colonies on potato dextrose agar (PDA) and on corn meal agar (CMA) coralloid-type mycelium, with abundant hyphal swellings, which were typically spherical and in clusters. Chlamydospores were either terminal or intercalary, and often occurred in characteristic grapelike clusters. Sporangia, which were produced in saline solution (1), were broadly ellipsoidal or ovoid, persistent, non-papillate and proliferous. The identification was confirmed by the electrophoresis of mycelial proteins on polyacrylamide slab gel. The electrophoretic patterns of total soluble proteins and eight isozymes (AKP [alkaline phosphatase], EST [esterase], FUM [fumarase], GLC [NAD-glucose dehydrogenase], G6PD [glucose-6-phosphate dehydrogenase], LDH [lactate dehydrogenase], MDH [malate dehydrogenase], and SOD [superoxide dismutase]) of the isolates from avocado were identical to those of two strains of P. cinnamomi, used as reference (isolate 70473 from International Mycological Institute, U.K., and an isolate from myrtle from the Institute of Plant Pathology, University of Catania, Italy). Conversely, the electrophoretic phenotype of the P. cinnamomi isolates from avocado was clearly distinct from those of reference strains of eight other species included in Waterhouse's taxonomic group VI. Pairings with isolates of a known mating type of P. cinnamomi, P. cryptogea, and P. drechsleri revealed that all the isolates from avocado were A2 mating type. It is possible that P. cinnamomi had been introduced into the experimental field on infected symptomless nursery trees. In Italy, root rot caused by P. cinnamomi could have a significant impact on commercial avocado plantings extending over about 20 ha. Moreover, this polyphagous pathogen may be a threat to other crops as well as to forest trees. References: (1) D. W. Chen and G. A. Zentmyer. Mycologia 62:397, 1970. (2) M. D. Coffey. Plant Dis. 71:1046, 1987. (3) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. American Phytopathological Society, St. Paul, MN. (4) H. Masago et al. Phytopathology 67:425, 1977.

Functional evidence for distinct interaction of hydrophobic arylisothiocyanates with the erythrocyte anion transport protein

Human erythrocytes were treated with various hydrophobic arylisothiocyanates under conditions which favor modification of distinct proteinaceous nucleophiles. The morphological appearance of phenylisothiocyanate-treated cells was discoid and membrane-bound hydrolases (human acetylcholinesterase, sheep phospholipase A2) were fully active following membrane modification. Noncharged hydrophobic arylisothiocyanates, including phenylisothiocyanate, beta-naphthylisothiocyanate and heterobifunctional azidoarylisothiocyanates inhibited [35S]-sulfate efflux irreversibly. Protection against modification-induced inhibition of sulfate transport was attained by the simultaneous presence of the specific reversible anion transport inhibitor 4,4'-dinitrostilbene-2,2'-disulfonate. Selective protection of a functionally relevant domain of band 3 is concluded to occur based on the above-derived information.