Preliminary note on potential use of forage crops for soil phytoremediation of dieldrin

The aim of this trial was to evaluate the feasibility of using tall fescue (Festuca arundinacea) and alfalfa (Medicago sativa) for phytoremediation of dieldrin. Experimental trial was carried out in greenhouse with temperature and light control. Each tested crop were seeded in individual pots (10 plants/pot) filled with contaminated soil (47 microg/kg dieldrin) and uncontaminated soil collected in sites located in the province of Latina (Italy). Samples of soil, root, and aerial part of plants were analysed at 3 and 6 months after seeding. The analytical determinations in soil and plant samples were carried out by GLC-ECD and confirmed by GLC-MS. After 6 months in the greenhouse, recoveries of dieldrin from soil planted with tall fescue and alfalfa were significantly lower than recoveries in unplanted control soil. Dieldrin residue values in root did not differ between the two different sampling times for each forage crop tested, but they were always higher in fescue than in alfalfa. Residue levels in aerial part were low (< 10 microg/kg) in the two forage crops. Preliminary results seem to confirm the ability of tested plants to enhance dissipation of dieldrin in soil at low level of contamination.

First Report of Aberia caffra and Quercus cerris as Hosts of Inonotus rickii

Inonotus rickii (Pat.) D. Reid (Hymenochaetaceae), widespread in tropical and subtropical countries, produces cankers and decay in several hardwoods. In Italy, it was recorded for the first time approximately 20 years ago on Parkinsonia sp. and Schinus molle L. in Sicily (2) and more recently on Acer negundo L. and Celtis australis L. in Rome (1). During May 2004, a survey was performed in Sicily in public and botanical gardens where the fungus had been detected in the past. Although the previously attacked plants had been removed, more trees were showing decline symptoms, with sparse foliage and some dieback. Typical brown, powdery masses of chlamydospores of I. rickii were observed near wounds or pruning cuts on Quercus cerris L. in Palermo and Sambucus nigra L. and Aberia caffra Hook. F. & Harv. in Catania. From each fungal specimen, fragments were isolated and cultured on malt agar. Cultures produced acute, thick-walled, brown setae (as much as 250 µm long) and abundant chlamydospores that were yellowish brown, thick walled, irregularly shaped, and 10 to 12 × 8 to 12 µm. Each isolate conformed to I. rickii (3). Cultures and voucher specimens have been deposited in the ISPaVe collection (PF40, PF41, and PF42) and the ROPV herbarium (772, 773, and 774). To our knowledge, this is the first report of I. rickii in living Q. cerris and A. caffra. S. nigra is a new host in Italy. This record shows that the pathogen has fully established itself in southern Europe where it may expand its host range. References: (1) T. Annesi et al. For. Pathol. 33:405, 2003. (2) M. Intini. Micol. Ital. 20:49, 1988. (3) J. A. Stalpers. Karstenia 40:167, 2000.

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).