The Colletotrichum acutatum species complex

Role of the beneficial phyllosphere microbiome in the defense against red clover anthracnose caused by Colletotrichum americae-borealis

Red clover (Trifolium pratense), a high-quality forage plant, faces significant threats from anthracnose in northeastern China, but the pathogen responsible remains unidentified. The phyllosphere microbiota is crucial in plantpathogen interactions, yet its role in the resistance of red clover to anthracnose is poorly understood. Using morphological, molecular, and multigene phylogenetic analyses, we identified Colletotrichum americae-borealis (Cab) as the pathogen that causes anthracnose in red clover in China. We also investigated changes in the phyllosphere microbiomes of highly resistant (XJ) and susceptible (SC) red clover materials after Cab infection, via 16S rRNA gene sequencing. The results revealed significant differences in bacterial α- and β-diversity, with novel microbial taxa and a complex microbial network emerging postinfection. Notably, after Cab inoculation, the Shannon diversity index in XJ exhibited more pronounced changes, manifested as an increase in the abundance of beneficial microorganisms such as Bacillus, Pantoea, and Pseudomonas. Network analysis revealed that the XJ microbiome was more complex and stable than the SC microbiome was, regardless of infection status. Bacillus J2, the dominant bacterium, significantly inhibited Cab growth in vitro and reduced the disease index by 33.4-47.7 % when it was reapplied to the leaf surface, suggesting its role in enhancing disease resistance. This study is the first to report that C. americae-borealis causes anthracnose in red clover in China, and demonstrates the potential of the beneficial bacterium J2 in enhancing disease resistance, providing insights into disease resistance mechanisms and the role of the phyllosphere microbiome in pathogen challenge.

Mango Microcosm: Unveiling the species diversity and pathogenic potential of fungi isolated from mango (Mangifera indica) in northern Thailand

This study aimed to identify fungal pathogens responsible for diseases affecting mango orchards and fruits in the primary mango-growing regions of northern Thailand, and to evaluate their pathogenicity against mango. Mango leaves, branches, and fruits showing fruit and leaf anthracnose, leaf spots, fruit rot, stem-end rot, fruit decline, leaf and stem blight, and shoot dieback were collected and examined from Chiang Rai, Kalasin, Nan, and Sakon Nakhon provinces located in northern Thailand. The isolated fungi were identified based on morphological characteristics and multi-locus phylogenetic analysis based on the most reliable markers and loci combinations suggested for each genus. This study illustrates and describes nine pathogenic genera, including eight known genera and one new genus, Pseudopallidocercospora. Botryosphaeria fabicerciana, Botryosphaeria scharifii, Colletotrichum asianum, Colletotrichum gigasporum, Colletotrichum guajavae, Colletotrichum musae, Colletotrichum plurivorum, Colletotrichum siamense, Diaporthe rosae, Diaporthe siamensis, Diaporthe subellipicola, Neofusicoccum sinoeucalypti, Neopestalotiopsis chrysea, Neopestalotiopsis cubana, Neopestalotiopsis dendrobii, Neopestalotiopsis psidii, Neopestalotiopsis rhododendri, Neoscytalidium dimidiatum, Pestalotiopsis humicola and Pestalotiopsis menhaiensis were identified as known species. Five new species, including Neopestalotiopsis mangiferae, Neopestalotiopsis mangifericola, Neopestalotiopsis mangiferigena, Pseudopallidocercospora mangiferae, and Zasmidium mangiferae were fully illustrated and justified. Moreover, this study reports twelve globally new host-fungus occurrences and six new geographical records. Furthermore, pathogenicity assessment revealed that the majority of the isolates (91.6 %) were pathogenic against mango, while their virulence was significantly different. C. asianum was found to be the predominant pathogenic species with a frequency of 31.6 %. Haplotype networks generated using ITS sequence data for 220 C. asianum strains isolated from mango across 14 countries revealed eight haplotypes, indicating high genetic diversity (Hd = 0.5936) within the species. However, the analysis did not reveal a clear grouping of isolates based on their country of origin.

Isolation and Biological Control of Colletotrichum sp. Causing Anthracnosis in Theobroma cacao L. in Chiapas, Mexico

Anthracnose is a phytosanitary issue caused by various species of Colletotrichum. This study aims to revise the presence of Colletotrichum in the south of Mexico (the Soconusco area in Chiapas) and assess the inhibitory capacity of Paenibacillus sp. NMA1017 against Colletotrichum in in vitro and field experiments. The study involved sampling pods with anthracnose from 17 sites in the Soconusco area, Chiapas, Mexico. The incidence of the disease ranged from 0.6 to 11.63%. A total of 142 isolates exhibiting the morphological characteristics of the Colletotrichum genus were obtained. Fifty selected isolates were identified using the ITS region and were classified as Colletotrichum gloeosporioides with 99% similarity. The concatenation of morphological and physiological characteristics resulted in nine main clusters. The in vitro test showed that Paenibacillus sp. NMA1017 inhibited the fungal growth of selected strains by 30-50%. The field experiments included three commercial biocontrol agents, Paenibacillus sp. NMA1017, and a water control. The incidence of anthracnose (control with water) ranged from 32 to 65%, while the commercial biocontrol agents and Paenibacillus showed an incidence range of 12 to 20%. These findings support the use of Paenibacillus sp. NMA1017 as a biocontrol agent for cacao anthracnose.

Characterization and Fungicide Sensitivity of Colletotrichum spp. from Capsicum Peppers in South Korea

Capsicum peppers, peppers from plants of the genus Capsicum (family Solanaceae), are widely cultivated in South Korea, where annual production was 92,756 tons in 2021, 54.4% higher than that of the previous year. Occurring throughout the production cycle, anthracnose is a major disease limiting commercial Capsicum pepper production worldwide, including in South Korea. This study investigates the diversity and pathogenicity of Colletotrichum species responsible for Capsicum pepper anthracnose in Gyeongbuk, South Korea, focusing on disease incidence and symptomatology in the field and the identification, morphological characteristics, pathogenicity, and fungicide sensitivity of the causative species. Disease incidence ranged from 30 to 50%, with samples categorized into three distinct symptom types, aiding accurate field diagnosis. Phylogenetic analysis classified 41 isolates into six species in the C. acutatum, gloeosporioides, and truncatum species complexes, revealing significant genetic diversity. Morphological characterization supported these identifications, providing a comprehensive profile. Pathogenicity tests confirmed that all identified species induced typical anthracnose lesions, with lesion size variations suggesting differential aggressiveness. Temperature significantly influenced mycelial growth, with optimal growth between 20 and 26°C and C. truncatum demonstrating high temperature tolerance. In vitro fungicide sensitivity tests showed variable responses, with tebuconazole being generally effective. These findings underscore the need for species-specific fungicide recommendations and highlight the importance of continuous monitoring of Colletotrichum species. Future research should explore the molecular mechanisms of pathogenicity, host specificity, and fungicide resistance, integrating these findings with breeding programs to develop resistant pepper varieties. This study provides critical insights for effective anthracnose management in pepper cultivation and future research directions.

Comparative transcriptome analysis reveals pathogenic mechanisms of Colletotrichum gloeosporioides in figs (Ficus carica L.) infection

Colletotrichum gloeosporioides is a pathogen responsible for causing anthracnose in Ficus carica L. (figs) and other fruits worldwide. Various stages of infection have been reported in C. gloeosporioides hosts; however, the molecular mechanisms underlying the differences in pathogen pathogenicity remain poorly understood. In this study, two strains (K7 and M5) of C. gloeosporioides isolated from fig leaves were compared. The K7 strain exhibited higher pathogenicity, faster mycelium growth, and quicker spore germination than M5 strain. To investigate the reasons for these differences, RNA sequencing was performed on samples collected 24 h post-infection from fig-infected K7 and M5 strains (K7-fig and M5-fig). Mycelia grown for 24 h on PDA plates (K7 and M5) were used as controls. A total of 143 differentially expressed genes (DEGs) were identified in C. gloeosporioides during fig infection, 79 DEGs of which were shared between K7 and M5. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of these 143 DEGs revealed significant enrichment in five pathways: aflatoxin biosynthesis, sphingolipid metabolism, aminoacyl-tRNA biosynthesis, nitrogen metabolism and the mitogen-activated protein kinase (MAPK) signaling pathway. Among the shared 79 DEGs, significant enrichment was observed in nitrogen metabolism, pentose phosphate pathway and aflatoxin biosynthesis in the infection process. Notably, pathways related to sphingolipid metabolism, aminoacyl-tRNA biosynthesis and MAPK signaling pathway-yeast in K7 were distinct from those in M5 during fig infection. These findings suggest that the high virulence of K7 may be associated with toxins produced via sphingolipid metabolism, aminoacyl-tRNA biosynthesis and MAPK signaling pathway-yeast. Therefore, this study provides valuable insights into the pathogenic biology of C. gloeosporioides.

Colletotrichum Species Causing Glomerella Leaf Spot and Apple Bitter Rot in the Southeastern United States Exhibit Disparities in Relative Frequency, Morphological Phenotype, and Quinone Outside Inhibitor Sensitivity

Glomerella leaf spot (GLS), Glomerella fruit rot (GFR), and apple bitter rot (ABR), caused by Colletotrichum spp., are among the most devastating apple diseases in the southeastern United States. Although several species have been identified as causal pathogens of GLS, GFR, and ABR, their relative frequency and fungicide sensitivity status in the southeastern United States is unknown. In total, 381 Colletotrichum isolates were obtained from symptomatic leaves and fruit from 18 conventionally managed apple orchards and two baseline populations in western North Carolina and Georgia in 2016 and 2017. Multilocus DNA sequence analysis revealed that C. chrysophilum was the predominant cause of GLS and GFR and C. fioriniae was the causal agent of ABR. Baseline and commercial populations of Colletotrichum spp. were evaluated for sensitivity to pyraclostrobin and trifloxystrobin, and no statistical differences in sensitivity between the two species were observed for conidial germination. However, the effective concentration that inhibited growth by 50% values were significantly lower for C. fioriniae compared with C. chrysophilum for both fungicides regarding mycelial inhibition. Isolates recovered from commercial orchards revealed that five populations of C. chrysophilum and one population of C. fioriniae had reduced sensitivity to trifloxystrobin, and one C. fioriniae population had reduced sensitivity to pyraclostrobin via conidial germination assays. The cytb gene for 27 isolates of C. fioriniae, C. chrysophilum, and C. fructicola with different quinone outside inhibitor (QoI) sensitivities revealed the G143A mutation in a single isolate of C. chrysophilum with insensitivity to both fungicides. The results of these studies suggest that two Colletotrichum spp. predominantly cause GLS and ABR in the southeastern United States and that a reduction in sensitivity to some QoI fungicides may be responsible for control failures. This study also provides a basis for monitoring shifts in QoI sensitivity in Colletotrichum spp. causing disease on apple in the southeastern United States.

Exploring mechanisms of resistance to fludioxonil in Colletotrichum fructicola

Colletotrichum fructicola is one of the most important species causing peach anthracnose around the world, including China. Fludioxonil has been effectively applied to control anthracnose disease as well as several important fungal diseases such as gray mold, leaf blight, early blight, corn stem rot, peanut root rot, rice evil seedling disease, and other diseases transmitted through seeds or soil. In this study, 39C. fructicola isolates were collected from different locations in Guizhou Province and Guangdong Province. A sensitive isolate of C. fructicola, previously thought to be naturally resistant to fludioxonil, was unexpectedly detected. No cross-resistance was found for fludioxonil with procymidone, prochloraz, and pyraclostrobin. Significant differences were observed between sensitive and resistant isolates in terms of mycelial growth rate and osmotic sensitivity experiments (4 %, 6 %, and 8 % NaCl), but no significant difference was found for sporulation. A novel mutation I880V was detected in the Os1 protein from one sensitive isolate. Molecular docking was used to explain the reversal of inherent resistance to sensitivity of C. fructicola to fludioxonil. Results showed that the wild type Os1 protein was docked against fludioxonil with a binding energy of -6.8 kj/mol, while it increased to -6.6 kj/mol between the mutated protein and fludioxonil. At the same time, different interactions were observed between wild type and mutated proteins with fludioxonil. These results suggest that the I880V mutation in the Os1 protein changed the conformation of the binding pocket, potentially leading to the reversal from resistance to sensitivity to fludioxonil. These findings are remarkable in demonstrating the fludioxonil resistance mechanism, and further studies such as genetic transformation and a range of molecular investigations are necessary to validate resistance mechanisms, elucidate the molecular pathways involved, and develop effective disease management strategies.

Can whole genome sequencing resolve taxonomic ambiguities in fungi? The case study of Colletotrichum associated with ferns

Introduction

The genus Colletotrichum comprises numerous fungal species with diverse ecological roles, including plant pathogenic, endophytic, and saprophytic lifestyles. Accurate species identification is crucial for understanding host-pathogen interactions, disease epidemiology, and fungal ecology. However, taxonomic classification within Colletotrichum remains challenging due to genetic complexity and phenotypic plasticity. Conventional approaches such as single-gene analyses and multilocus sequence typing (MLST) frequently fail to resolve closely related taxa, leading to misidentifications that hinder species delimitation and comparative evolutionary studies. Whole-genome sequencing (WGS) offers a promising alternative by providing genome-wide resolution for phylogenetic analysis. This study investigates Colletotrichum isolates associated with the fern Rumohra adiantiformis and evaluates the effectiveness of WGS in addressing taxonomic uncertainties.

Methods

A total of 18 Colletotrichum isolates, including fern-associated strains, were analyzed. Genomic DNA was extracted and sequenced using the Illumina NovaSeq platform. High-quality genome assemblies were generated, and gene prediction was conducted using AUGUSTUS. Orthogroup assignment and phylogenomic analysis were performed based on single-copy orthologs, and phylogenetic trees were constructed using MLST and WGS-based approaches. Comparative analyses were carried out to assess the taxonomic resolution provided by WGS in relation to traditional methods.

Results

Genome-wide phylogenomic analysis revealed distinct evolutionary lineages among Colletotrichum isolates that MLST failed to resolve, highlighting host and geographic differentiation. High-quality genome assemblies were obtained, with 98.3% of genes assigned to orthogroups, indicating strong genomic conservation. Phylogenetic analyses confirmed a close relationship between Rumohra adiantiformis-associated isolates and Colletotrichum filicis, reinforcing the effectiveness of WGS in species identification.

Discussion

These findings demonstrate the superiority of WGS over MLST in resolving species boundaries and reconstructing evolutionary relationships. The enhanced resolution provided by genome-wide data enables more accurate taxonomic classification, reducing misidentifications and improving our understanding of fungal biodiversity. By refining Colletotrichum taxonomy, WGS facilitates ecological and pathogenic studies, offering a robust framework for future research in fungal systematics and plant pathology. As sequencing technologies continue to advance, WGS is expected to become a standard tool for fungal species delineation and evolutionary studies.

Diversity and Pathogenicity of Colletotrichum Species Causing Coffee Anthracnose in China

Coffee is a significant traded commodity for developing countries. Among the various diseases affecting coffee, anthracnose caused by Colletotrichum spp. has re-emerged as a major constraint on global coffee production. To better understand the Colletotrichum species complex associated with coffee anthracnose, we characterized Colletotrichum spp. using a combination of phenotypic traits, MAT1-2 (ApMat) gene analysis, multi-locus phylogenetic (ITS, ACT, CHS-1, and GAPDH), and pathogenicity assays. A total of 74 Colletotrichum isolates were collected from coffee plants exhibiting anthracnose symptoms across nine coffee plantations in China. Among these, 55 isolates were identified as the C. gloeosporioides species complex using the ApMat locus, while the remaining 19 isolates were identified through multi-locus phylogenetic analyses. The isolates represented seven Colletotrichum species from five species complexes: C. gloeosporioides (including C. siamense, C. nupharicola, and C. theobromicola), C. boninens (C. karstii), C. gigasporum (C. gigasporum), C. orchidearum (C. cliviicola), and C. magnum (C. brevisporum). This is the first report of C. nupharicola and C. cliviicola causing coffee anthracnose worldwide, and the first report of C. nupharicola in China. Pathogenicity tests confirmed that all seven species were capable of infecting coffee leaves. This research enhances our understanding of the Colletotrichum species responsible for coffee anthracnose, and provides valuable insights for developing effective disease management strategies.

Two volatiles from anthracnose-infected blueberries trigger electrophysiological and aversive behavioral responses in Drosophila suzukii (Diptera: Drosophilidae)

Native to Southeast Asia, the spotted-wing drosophila (Drosophila suzukii Matsumura) is an economically important invasive pest of thin-skinned fruits such as raspberries, blueberries, and strawberries worldwide. To reduce the reliance on insecticides for managing this pest, alternative strategies like behavioral manipulation are needed. Previous studies have shown that D. suzukii adults avoid blueberry fruits infected with the fungal pathogen Colletotrichum fioriniae Marcelino & Gouli, which causes anthracnose fruit rot, leading to the identification of 9 potential repellent compounds. In this study, we further investigated the two most potent of these compounds-ethyl butanoate and ethyl (E)-but-2-enoate-to assess their repellent properties on the antennal and behavioral responses of D. suzukii. Electroantennogram (EAG) assays revealed that both esters elicited similar dose-dependent responses in male and female D. suzukii, which were often stronger than those triggered by 2-pentylfuran, a known repellent of this species. Additionally, we examined the behavioral responses of adult D. suzukii to these 3 repellent compounds under semi-field and field conditions using outdoor cages containing potted and planted blueberry bushes, respectively. Results from the cage studies showed that all 3 tested compounds can significantly reduce D. suzukii oviposition and adult emergence from blueberry fruits, with ethyl (E)-but-2-enoate sometimes outperforming the other compounds. Our findings indicate that the esters ethyl butanoate and ethyl (E)-but-2-enoate, which are induced from C. fioriniae-infected blueberries, elicit dose-dependent effects on D. suzukii antennae and act as effective oviposition deterrents. This supports their potential as promising tools for managing this pest through behavioral strategies.

Characterization of Fungal Pathogens Causing Blueberry Fruit Rot Disease in China

Blueberry has been a burgeoning fruit in China in recent years, but its perishable nature places a constant strain on industrial development. To determine the pathogens infecting blueberry fruits, diseased samples were collected from Guizhou and Fujian Provinces. Isolates from the samples were identified by morphological characterization and phylogenetic analyses. Pathogenicity assays were conducted on fresh blueberry fruits using spore suspensions. Sixteen isolates were identified as seven species, namely, Botryosphaeria dothidea, Botrytis cinerea, Cladosporium guizhouense, Colletotrichum fioriniae, Diaporthe anacardii, Fusarium annulatum, and Neopestalotiopsis surinamensis, and their pathogenicity on blueberry fruits were confirmed following Koch's postulates. The current study reported Cladosporium guizhouense, Fusarium annulatum, and Neopestalotiopsis surinamensis for the first time on blueberry. The study (1) demonstrated that fruit rot disease results from a mixed infection of multiple pathogens; and (2) expanded the understanding of causal agents of blueberry fruit rot during the growth stage, highlighting their potential as latent pathogens that contribute to post-harvest losses. Relevant results provide a reference for the etiological research and disease management in blueberry fruit diseases.

Uncovering the Host Range-Lifestyle Relationship in the Endophytic and Anthracnose Pathogenic Genus Colletotrichum

Colletotrichum includes agriculturally and scientifically important pathogens that infect numerous plants. They can also adopt an endophytic lifestyle, refraining from causing disease and/or even promoting plant growth when inoculated on a non-susceptible host. In this manner, the host range of a Colletotrichum fungus can shift, depending on whether it exhibits endophytic or pathogenic lifestyles. Some fungi, such as Colletotrichum tofieldiae, can even shift between pathogenicity and endophytism within the same host depending on the environmental conditions. Here, we aim to disentangle the relationship between lifestyle and host range in Colletotrichum. Specifically, we aim to demonstrate that lifestyle is dependent on the host colonized in many Colletotrichum fungi. We discuss the ways in which pathogenic Colletotrichum species may act endophytically on alternative hosts, how comparative genomics has uncovered candidate molecules (namely effectors, CAZymes, and secondary metabolites) underlying fungal lifestyle, and the merits of using endophytic fungi alongside pathogenic fungi in research, which facilitates the use of reverse genetics to uncover molecular determinants of lifestyle. In particular, we reference the Arabidopsis thaliana-Colletotrichum tofieldiae study system as a model for elucidating the dual roles of plant-fungus interactions, both endophytic and pathogenic, through integrative omics approaches and reverse genetics. This is because C. tofieldiae contains closely related pathogens and endophytes, making it an ideal model for identifying candidate determinants of lifestyle. This approach could identify key molecular targets for effective pathogen management in agriculture. Lastly, we propose a model in which pathogenic lifestyle occupies a different host range than the endophytic lifestyle. This will enhance our understanding of pathogenicity and endophytism in a globally significant fungal genus and lay the groundwork for future research examining molecular determinants of lifestyle in plant-associated fungi.

A new name for an old problem-Colletotrichum cigarro is the cause of St John's wilt of Hypericum perforatum

A major problem for St John's wort (Hypericum perforatum) is St John's wilt, which can lead to reduced crop yields and even complete crop losses. In the past, the pathogen was referred to as Colletotrichum gloeosporioides or occasionally as Colletotrichum cf. gloeosporioides based on morphology. Although a strain from this host had been re-identified as C. cigarro in taxonomic studies, there is uncertainty about the identity of the St John's wilt pathogen, which is generally still addressed as C. gloeosporioides in applied science. In a multi-locus [internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), and glutamine synthetase (GS)] analysis of the C. gloeosporioides species complex, all isolates obtained from newly collected symptomatic H. perforatum stems and seeds from Germany and Switzerland were identified as C. cigarro. Although they belonged to the same haplotype, the morphology of the isolates was very variable. Pathogenicity tests demonstrated that only C. cigarro strains from H. perforatum cause symptoms on H. perforatum, whereas other Colletotrichum species tested only caused latent infection of H. perforatum.

Diversity of Colletotrichum Species Causing Anthracnose in Chayote in Brazil, with a Description of Two New Species in the C. magnum Complex

Anthracnose caused by Colletotrichum species is the most important disease of chayote (Sicyos edulis) in Brazil. The etiology of chayote anthracnose has been assigned to the species C. orbiculare, an important plant pathogenic fungus also reported as the causal agent of anthracnose in other cucurbits worldwide. However, there is no recent survey of the Colletotrichum species causing anthracnose in chayote in Brazil. In this study, Colletotrichum isolates associated with anthracnose on the fruit and leaves of chayote, from various producing regions in Brazil, were collected and identified. Haplotype analysis based on sequences of the β-tubulin genomic region (TUB2) of 44 Colletotrichum isolates was carried out as a first measure of genetic diversity. A subset of 22 isolates were sequenced using the partial sequences of actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the rDNA ITS (ITS) region. Maximum likelihood analysis was performed using the concatenated sequences. The multilocus sequence analysis revealed four previously described species, Colletotrichum chrysophilum, C. menezesiae, C. plurivorum, and C. karsti, and two novel species, named C. cucurbitacearum and C. sicyi. All species were able to induce typical symptoms of anthracnose in chayote fruits but varied in their aggressiveness. The species C. menezesiae and C. sicyi were the most aggressive, while C. plurivorum was the least aggressive. The species C. orbiculare was not found to cause chayote anthracnose in Brazil.

Identification, Pathogenicity, and Fungicide Sensitivity of Colletotrichum Species Associated with Anthracnose on Italian Ryegrass in Southwestern China

Italian ryegrass (Lolium multiflorum L.) is widely cultivated as an important forage grass worldwide because of its high nutritional value and good palatability. Anthracnose caused by Colletotrichum species was a common and new emerging disease of Italian ryegrass. In this study, 88 Colletotrichum isolates were collected from diseased leaves of Italian ryegrass planting regions in Sichuan, Chongqing, and Guizhou provinces of southwestern China between 2019 and 2022. By the pure culture technique, 15 representative single-spore isolates were obtained for further study. Multilocus phylogenetic analysis coupled with morphological features showed that these isolates were finally identified as six new record species: C. cereale of the C. graminicola species complex, C. fioriniae and C. nymphaeae of the C. acutatum species complex, C. boninense and C. citricola of the C. boninense species complex, and C. nageiae. Pathogenicity tests indicated that all species could induce anthracnose symptoms; of these, C. cereale was more invasive than other species, followed by C. fioriniae, C. nageiae, C. citricola, and C. boninense; C. nymphaeae was the weakest pathogenic species to Italian ryegrass plants (P ≤ 0.05). Fungicide sensitivity assays showed that iprodione, propineb, and oxime·tebuconazole had strong inhibitory effects on the mycelial growth of six Colletotrichum species; in addition, azoxystrobin and fludioxonil also significantly inhibited the mycelial growth of C. nymphaeae and C. fioriniae, respectively. These results provide the basis for the diagnosis and detection in the field, pathogen identification, and management of anthracnose on Italian ryegrass.

Comparative Genomics Reveals Sources of Genetic Variability in the Asexual Fungal Plant Pathogen Colletotrichum lupini

Fungal plant pathogens cause major crop losses worldwide, with many featuring compartmentalised genomes that include both core and accessory regions, which are believed to drive adaptation. The highly host-specific fungus Colletotrichum lupini greatly impacts lupin (Lupinus spp.) cultivation. This pathogen is part of clade 1 of the C. acutatum species complex and comprises four genetically uniform, presumably clonal, lineages (I-IV). Despite this, variation in virulence and morphology has been observed within these lineages. To investigate the potential sources of genetic variability in this asexual fungus, we compared the genomes of 16 C. lupini strains and 17 related Colletotrichum species. Phylogenomics confirmed the presence of four distinct lineages, but further examination based on genome size, gene content, transposable elements (TEs), and deletions revealed that lineage II could be split into two groups, II-A and II-B. TE content varied between lineages and correlated strongly with genome size variation, supporting a role for TEs in genome expansion in this species. Pangenome analysis revealed a highly variable accessory genome, including a minichromosome present in lineages II, III, and IV, but absent in lineage I. Accessory genes and effectors appeared to cluster in proximity to TEs. Presence/absence variation of putative effectors was lineage-specific, suggesting that these genes play a crucial role in determining host range. Notably, no effectors were found on the TE-rich minichromosome. Our findings shed light on the potential mechanisms generating genetic diversity in this asexual fungal pathogen that could aid future disease management.

Apple Bitter Rot and Glomerella Leaf Spot: A Comprehensive Review of Causal Species and Their Biology, Fungicide Sensitivities, and Management Strategies

Bitter rot and Glomerella leaf spot (GLS) are two distinct diseases of apple fruit and foliage caused by members of the ascomycete fungal genus Colletotrichum. Although GLS is restricted to subtropical and, in some areas, to temperate climates, bitter rot is responsible for significant yield loss worldwide, particularly during the postharvest period. Initially thought to be caused by just two species of Colletotrichum, C. acutatum, and C. gloeosporioides, advances in molecular biology and sequencing techniques enabled the identification of 25 different species capable of causing bitter rot and/or GLS of apple belonging to the C. gloeosporioides species complex (CGSC), C. acutatum species complex (CASC), and C. boninense species complex (CBSC). Three species (C. gloeosporioides, C. fructicola, and C. chrysophilum) of CGSC cause both bitter rot and GLS, 18 species (6 of CGSC and 12 of CASC) only cause bitter rot, and 4 species (C. aenigma and C. asianum of CGSC, C. limetticola of CASC, and C. karsti of CBSC) only cause GLS. These species were found to differ in their geographical distribution, environmental and host tissue preference, pathogenicity, and fungicide sensitivities. In this review, we summarize the distribution, life cycle, and pathogenicity mechanisms of all currently known Colletotrichum species responsible for bitter rot and GLS of apple. Furthermore, we describe known apple defense mechanisms and management strategies for the control of these economically significant pathogens and identify gaps in our present understanding for future research.

Fungal community and toxigenic taxa in chestnut fruits in postharvest conditioning process and storage

BACKGROUND

Chestnut fruit quality is affected by fungal contamination. The study of the patterns of contamination in the postharvest is crucial to individuate the critical phases and propose solutions. To understand how fungal colonization varies on fruits, the composition of mycobiota was investigated in postharvest handling and in between tissues (shell and kernel).

RESULTS

Fungal sequences were clustered into 308 operational taxonomic units (OTUs). Biodiversity was higher in shell than kernel tissues. Results evidenced the risk of new contamination in specific phases such as the 'cold bath' and storage. Genera known as mycotoxin producers were detected in all phases. Specifically, 47 OTUs belonging to Penicillium, eight to Fusarium and two to Aspergillus genera were identified. While Fusarium spp. was sensitive to 'warm bath' phase, Penicillium spp. was largely insensitive and accumulated in storage conditions. Surprisingly, Aspergillus spp. was poorly represented. Aflatoxin, ochratoxin A, fumonisins and T-2/HT-2 detection was performed for shell and kernel, and process phases. Higher contamination was observed on shell than in kernel samples. While aflatoxins were within the European Union (EU) limits for dry fruits, Ochratoxin exceeded the EU limits. The present study represents the first report of fumonisins and T-2/HT-2 detection in chestnuts.

CONCLUSION

Fungal contamination taxa is high in chestnut fruits following postharvest handling and storage. A parametrization of process phases such as the 'warm bath' is functional to reduce the risk for some taxa. For other spoilage and mycotoxigenic genera strict sanitation procedures of equipment and water must be individuated and implemented to reduce their impact. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Colletotrichum caladii sp. nov. Causing Anthracnose Leaf Spot of Caladium × hortulanum (Araceae) in Florida, U.S.A

Caladium (Caladium × hortulanum) is an ornamental plant popular for its variable and colorful foliage. In 2020, plants showing leaf spots and blight, typical of anthracnose, were found in a field trial at the University of Florida's Gulf Coast Research and Education Center in Wimauma, Florida, U.S.A. Leaf samples consistently yielded a Colletotrichum-like species with curved conidia and abundant setae production in the acervuli. The internal transcribed spacer (ITS), partial sequences of the glyceraldehyde-3-phosphate dehydrogenase gene (gapdh), actin gene (act), chitin synthase 1 gene (chs-1), beta-tubulin gene (tub2), and histone3 gene (his3) were amplified and sequenced. BLASTN searches in the NCBI GenBank database revealed similarities to species of the Colletotrichum truncatum species complex. Phylogenetic analyses using multilocus sequence data supports a distinct species within this complex, with the closest related species being C. curcumae. Based on morphological and phylogenetic analyses, a new species of Colletotrichum, named C. caladii, is reported. Pathogenicity assays and subsequent isolation confirmed that this species was the causal agent of the disease.

Effect of temperature on in vitro germination and growth of Colletotrichum fioriniae, a new emerging pathogen of olive fruits

Olive anthracnose induced by different Colletotrichum species causes dramatic losses of fruit yield and oil quality. The increasing incidence of Colletotrichum fioriniae (Colletotrichum acutatum species complex) as causal agent of olive anthracnose in Italy, is endorsing new studies on its biology, ecology, and environmental factors such as temperature. Five isolates from different sampling sites in Lazio region (Central Italy) were studied under controlled laboratory conditions aiming to better understand the differences of thermal development among the isolates and to lay the foundations of a future mathematical model able to describe the key aspects of the pathogen's life cycle. The mycelial growth rate and the conidial germination rate were assessed at seven different constant temperatures (5, 10, 15, 20, 25, 30, and 35°C) and fixed relative humidity (100% RH). The obtained dataset was analysed to estimate the parameters of mathematical functions that connect the mycelial growth rate and the spore germination with the environmental temperature. The parameters set provided as the result of this study constitute a key step forward in the biological knowledge of the species and the basis for future formulations of mathematical models that might be the core of decision support systems in an integrated pest management framework.

Cestrum tomentosum L.f. Extracts against Colletotrichum scovillei by Altering Cell Membrane Permeability and Inducing ROS Accumulation

Chili pepper anthracnose, caused by Colletotrichum spp., is a significant biotic stress affecting chili fruits globally. While fungicide application is commonly used for disease management due to its efficiency and costeffectiveness, excessive use poses risks to human health and the environment. Botanical fungicides offer advantages such as rapid degradation and low toxicity to mammals, making them increasingly popular for sustainable plant disease control. This study investigated the antifungal properties of Cestrum tomentosum L.f. crude extracts (CTCE) against Colletotrichum scovillei. The results demonstrated that CTCE effectively inhibited conidia germination and germ tube elongation at 40 µg/ml concentrations. Moreover, CTCE exhibited strong antifungal activity against C. scovillei mycelial growth, with an EC50 value of 18.81 µg/ml. In vivo experiments confirmed the protective and curative effects of CTCE on chili pepper fruits infected with C. scovillei. XTT analysis showed that the CTCE could significantly inhibit the cell viability of C. scovillei. Mechanistic studies revealed that CTCE disrupted the plasma membrane integrity of C. scovillei and induced the accumulation of reactive oxygen species in hyphal cells. These findings highlight CTCE as a promising eco-friendly botanical fungicide for managing C. scovillei infections in chili peppers.

Colletotrichum Species Associated with Apple Bitter Rot and Glomerella Leaf Spot: A Comprehensive Overview

Species of the genus Colletotrichum are among the most important plant pathogens globally, as they are capable of infecting many hosts-apple (Malus spp.) and other fruit and woody plant species-but also vegetable crops, cereals, legumes, and other annual and perennial herbaceous plants. The apple (Malus spp.) is attacked by various species from the genus Colletotrichum, whereby 27 different species from this genus have been described as the causative agents of apple bitter rot (ABR) and 15 as the cause of Glomerella leaf spot (GLS). These species generally belong to one of three species complexes: Colletotrichum acutatum, Colletotrichum gloeosporioides, and Colletotrichum boninense. The largest number of apple pathogens of the genus Colletotrichum belong to the species complex C. acutatum and C. gloeosporioides. However, further data on these species and the interactions between the species complexes of the genus Colletotrichum that cause these two apple diseases is needed for the development of effective control measures, thus ensuring successful and profitable apple cultivation. To contribute to this endeavor, a comprehensive review of the causative agents of ABR and GLS from the genus Colletotrichum is provided. In addition to presenting the species' current names, distribution, economic significance, and the symptoms they cause in apple, their development cycle, epidemiology, and molecular detection strategies are described, with a particular emphasis on control measures.

Three new species of Colletotrichum (Glomerellales, Glomerellaceae) associated with walnut (Juglansregia) anthracnose from China

Colletotrichum species are significant pathogens of various economic plant hosts worldwide. In this study, 45 Colletotrichum isolates were obtained from symptomatic walnut leaves of walnut anthracnose in Shaanxi and Sichuan Provinces. In conjunction with morphological evidence and multi-gene phylogenetic analyses of internal transcribed spacer (ITS), actin (act), chitin synthase 1 (chs1), glyceraldehyde-3-phosphate dehydrogenase (gapdh) and beta-tubulin (tub2) sequences support the introduction of three new species, namely Colletotrichumcordae, C.guangyuanense and C.juglandium. Five species of Colletotrichum were identified to be C.fioriniae of the C.acutatum species complex, C.karsti of the C.boninense species complex, C.gloeosporioides, C.mengyinense and C.siamense of the C.gloeosporioides species complex. The three new species are described and illustrated in this paper and compared with taxa in the Colletotrichumgloeosporioides species complex. The current results improve the understanding of Colletotrichum species causing walnut anthracnose in China.

PCR-Based Detection for the Quarantine Fungus Colletotrichum kahawae, a Biosecurity Threat to the Coffee (Coffea arabica) Industry Worldwide

Coffee berry disease is caused by Colletotrichum kahawae, a quarantine fungus still absent from most coffee-producing countries. Given the potential adverse effects on coffee berry production, it is a severe worldwide threat to farmers and industry. Current biosecurity management focuses on exclusion by applying quarantine measures, including the certification of coffee plants and their products. However, methods for detecting C. kahawae by National Plant Protection Organization (NPPO) laboratories still need approval. This research aims to functionally demonstrate, standardize, and validate a method for detecting and discriminating C. kahawae from other Colletotrichum species that may be present in coffee plant samples. The method proposes to use an end-point PCR marker for the mating type gene (MAT1-2-1) and a confirmatory test with a real-time quantitative PCR (qPCR) marker developed on the glutamine synthetase gene. The C. kahawae amplicons for the Cen-CkM10 qPCR marker exhibited specific melting temperature values and high-resolution melt profiles that could be readily differentiated from other tested species, including their relatives. Given the fungus's quarantine status, specificity was tested using artificial mixtures of DNA of C. kahawae with other Colletotrichum species and coffee plant DNA. The described method will enable NPPOs in coffee-producing and exporting countries, especially Colombia, to prevent this pathogen's entry, establishment, and spread.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Colletotrichum species (Glomerellales, Glomerellaceae) causing walnut anthracnose in China

Colletotrichum species can function as plant pathogens, saprobes or endophytes on a wide variety of plant hosts and are considered amongst the ten most significant genera of plant pathogens globally. China contributes almost half the walnut production in the world. However, Colletotrichum species occurring on walnut remain largely unresolved in China. To explore the Colletotrichum species found on walnut in China, 470 walnut fruit or leaf samples with anthracnose were collected from 14 main walnut-producing regions across seven provinces. A total of 165 Colletotrichum strains were isolated from these samples. The Colletotrichum isolates were identified, based on morphological characteristics and sequence analyses of ACT, CHS-1, GAPDH, ITS and TUB2. Twelve species, including 11 known Colletotrichum species (C.boninense, C.citrulli, C.fioriniae, C.fructicola, C.godetiae, C.juglandicola, C.karsti, C.mengyinense, C.pandanicola, C.peakense and C.siamense) and a novel species (C.chinensis sp. nov.) were identified. The species distribution revealed regional prevalence as follows: C.mengyinense was the most dominant species in Gansu, C.mengyinense and C.siamense in Shandong, C.chinensis in Beijing, C.pandanicola in Shaanxi and C.godetiae in Yunnan. Colletotrichumsiamense was the sole species isolated in Sichuan and Xinjiang Provinces. Koch's postulates were fulfilled, demonstrating that all 12 species cause anthracnose on walnut. This is the first report of C.boninense, C.citrulli and C.karsti as pathogens of walnut anthracnose worldwide.

Profiling of the Citrus Leaf Endophytic Mycobiota Reveals Abundant Pathogen-Related Fungal Groups

Plant endophytic microbial communities consist of many latent plant pathogens and, also, many pathogen-related species with reduced virulence. Though with a long history of co-evolution, the diversity and composition of the endophytic mycobiota, especially the pathogen-related fungal groups, has been under-investigated in Citrus (C.). Based on the amplicon sequencing of fungal internal transcribed spacer (ITS), the leaf endophytic mycobiota were profiled on citrus varieties from different citrus-producing regions. The pomelo variety shared significantly distinctive leaf mycobiota when compared to the mandarin and sweet orange; these conform to their host genetic relationships. In addition, a data set of 241 citrus-related fungi, including 171 (71%) pathogens and potential pathogens, was summarized from previous studies. Under the criteria of local BLAST (covered ITS nucleotide ≥ 150 bp, sequence identity ≥ 99%), a total of 935 fungal operational taxonomic units (OTUs) were assigned to 62 pathogen-related fungal groups, representing 14.9% of the relative abundance in the whole community. Of which, the top groups consisted of Colletotrichum gloeosporioides (mean relative abundance, 4.3%), Co. citricola and Co. karstii (2.7%), Zasmidium citri-griseum (2.4%), and Z. fructigenum (1.4%). At the genus level, the ratio of the pathogen-related fungal groups in 64% of fungal genera (16 out of 25) exceeded 50%, which are the solely or mainly occurring fungi of their genus in citrus. Our study suggests that the leaf endophytic compartment may be an important place for the growth of latent pathogens.

Managing fruit rot diseases of Vaccinium corymbosum

Blueberry is an important perennial fruit crop with expanding consumption and production worldwide. Consumer demand for blueberries has grown due to the desirable flavor and numerous health benefits, and fresh market production in the U.S. has risen in turn. U.S. imports have also increased to satisfy year-round consumer demand for fresh blueberries. Pre- and post-harvest fruit diseases such as anthracnose (caused by Colletotrichum spp.) and botrytis fruit rot (caused by Botrytis spp.) have a significant impact on fruit quality and consumer acceptance. These are also among the most difficult diseases to control in the blueberry cropping system. These latent pathogens can cause significant losses both in the field, and especially during transport and marketplace storage. Although both diseases result in rotted fruit, the biology and infection strategies of the causal pathogens are very different, and the management strategies differ. Innovations for management, such as improved molecular detection assays for fungicide resistance, postharvest imaging, breeding resistant cultivars, and biopesticides have been developed for improved fruit quality. Development and integration of new strategies is critical for the long-term success of the blueberry industry.

Fungicide resistance in Colletotrichum fructicola and Colletotrichum siamense causing peach anthracnose in China

Peach is one of the popular and economically important fruit crops in China. Peach cultivation is hampered due to attacks of anthracnose disease, causing significant economic losses. Colletotrichum fructicola and Colletotrichum siamense belong to the Colletotrichum gloeosporioides species complex and are considered major pathogens of peach anthracnose. Application of different groups of fungicides is a routine approach for controlling this disease. However, fungicide resistance is a significant drawback in managing peach anthracnose nowadays. In this study, 39 isolates of C. fructicola and 41 isolates of C. siamense were collected from different locations in various provinces in China. The sensitivity of C. fructicola and C. siamense to some commonly used fungicides, i.e., carbendazim, iprodione, fluopyram, and propiconazole, was determined. All the isolates of C. fructicola collected from Guangdong province showed high resistance to carbendazim, whereas isolates collected from Guizhou province were sensitive. In C. siamense, isolates collected from Hebei province showed moderate resistance, while those from Shandong province were sensitive to carbendazim. On the other hand, all the isolates of C. fructicola and C. siamense showed high resistance to the dicarboximide (DCF) fungicide iprodione and succinate dehydrogenase inhibitor (SDHI) fungicide fluopyram. However, they are all sensitive to the demethylation inhibitor (DMI) fungicide propiconazole. Positive cross-resistance was observed between carbendazim and benomyl as they are members of the same methyl benzimidazole carbamate (MBC) group. While no correlation of sensitivity was observed between different groups of fungicides. No significant differences were found in each fitness parameter between carbendazim-resistant and sensitive isolates in both species. Molecular characterization of the β-tubulin 2 (TUB2) gene revealed that in C. fructicola, the E198A point mutation was the determinant for the high resistance to carbendazim, while the F200Y point mutation was linked with the moderate resistance to carbendazim in C. siamense. Based on the results of this study, DMI fungicides, e.g., propiconazole or prochloraz could be used to control peach anthracnose, especially at locations where the pathogens have already developed the resistance to carbendazim and other fungicides.

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

Quantitative Trait Loci Analysis and Marker Development for Fruit Rot Resistance in Cranberry Shows Potential Genetic Association with Epicuticular Wax

Fruit rot is a fungal disease complex that threatens cranberry yields in North American growing operations. Management of fruit rot is especially difficult because of the diversity of the infecting fungal species, and although infections take place early in the season, the pathogens usually remain latent in the ovary until the fruit ripen. Control methods heavily rely on fungicide applications, a practice that may be limited in viability long term. Breeding for fruit rot resistance (FRR) is essential for sustainable production. It is likely that field resistance is multifaceted and involves a myriad of traits that fortify cranberry plants against the biotic and abiotic stresses contributing to fruit rot. In this study, we identified quantitative trait loci (QTL) for FRR in a segregating population. Interestingly, a QTL associated with resistance was found to overlap with one associated with fruit epicuticular wax (ECW). A single-nucleotide polymorphism genotyping assay successfully identified accessions that exhibit the desired phenotypes (i.e., less rot and more ECW), thus making it a useful tool for marker-assisted selection. Candidate genes that may contribute to FRR and ECW were also identified. This work will expedite breeding for improved cranberry fruit quality.

Mitigating Emerging and Reemerging Diseases of Fruit and Vegetable Crops in a Changing Climate

Fruit and vegetable crops are important sources of nutrition and income globally. Producing these high-value crops requires significant investment of often scarce resources, and, therefore, the risks associated with climate change and accompanying disease pressures are especially important. Climate change influences the occurrence and pressure of plant diseases, enabling new pathogens to emerge and old enemies to reemerge. Specific environmental changes attributed to climate change, particularly temperature fluctuations and intense rainfall events, greatly alter fruit and vegetable disease incidence and severity. In turn, fruit and vegetable microbiomes, and subsequently overall plant health, are also affected by climate change. Changing disease pressures cause growers and researchers to reassess disease management and climate change adaptation strategies. Approaches such as climate smart integrated pest management, smart sprayer technology, protected culture cultivation, advanced diagnostics, and new soilborne disease management strategies are providing new tools for specialty crops growers. Researchers and educators need to work closely with growers to establish fruit and vegetable production systems that are resilient and responsive to changing climates. This review explores the effects of climate change on specialty food crops, pathogens, insect vectors, and pathosystems, as well as adaptations needed to ensure optimal plant health and environmental and economic sustainability.

New Species-Specific Real-Time PCR Assays for Colletotrichum Species Causing Bitter Rot of Apple

Bitter rot of apple is an economically important worldwide disease caused by different Colletotrichum species, depending on many factors such as climate, geography, other hosts, and crop management practices. Culture, morphology, and single-locus sequencing-based methods for identifying the Colletotrichum species are severely limited in effectiveness, while the multilocus sequence typing methods available for delineating species are costly, time-intensive, and require high expertise. We developed species-specific hydrolysis probe real-time PCR assays for the following nine Colletotrichum species causing bitter rot in the Mid-Atlantic U.S.A.: C. fructicola, C. chrysophilum, C. noveboracense, C. gloeosporioides s.s., C. henanense, C. siamense and C. theobromicola from the C. gloeosporioides species complex, and C. fioriniae and C. nymphaeae from the C. acutatum species complex. After searching 14 gene regions, we designed primers and probes in 5 of them for the nine target species. Four primer-probe set pairs were able to be duplexed. Sensitivity tests showed as little as 0.5 pg DNA were detectable. These real-time PCR assays will provide rapid and reliable identification of these key Colletotrichum species and will be critically important for studies aiming to elucidate their biology, epidemiology, and management on apples as the number one produced and consumed tree fruit in the U.S.A.

Complete genome sequence of a novel alternavirus isolated from the phytopathogenic fungus Colletotrichum fioriniae

A novel double-strand RNA (dsRNA) mycovirus, named "Colletotrichum fioriniae alternavirus1" (CfAV1), was isolated from the strain CX7 of Colletotrichum fioriniae, the causal agent of walnut anthracnose. The complete genome of CfAV1 is composed of three dsRNA segments: dsRNA1 (3528 bp), dsRNA2 (2485 bp), and dsRNA3 (2481 bp). The RNA-dependent RNA polymerase (RdRp) is encoded by dsRNA1, while both dsRNA2 and dsRNA3 encode hypothetical proteins. Based on multiple sequence alignments and phylogenetic analysis, CfAV1 is identified as a new member of the family Alternaviridae. This is the first report of an alternavirus that infects the phytopathogenic fungus C. fioriniae.

Diversity of Leaf Fungal Endophytes from Two Coffea arabica Varieties and Antagonism towards Coffee Leaf Rust

Coffee has immense value as a worldwide-appreciated commodity. However, its production faces the effects of climate change and the spread of severe diseases such as coffee leaf rust (CLR). The exploration of fungal endophytes associated with Coffea sp. has already found the existence of nearly 600 fungal species, but their role in the plants remains practically unknown. We have researched the diversity of leaf fungal endophytes in two Coffea arabica varieties: one susceptible and one resistant to CLR. Then, we conducted cross-infection essays with four common endophyte species (three Colletotrichum sp. and Xylaria sp. 1) and Hemileia vastatrix (CLR) in leaf discs, to investigate the interaction of the endophytes on CLR colonisation success and severity of infection. Two Colletotrichum sp., when inoculated 72 h before H. vastatrix, prevented the colonisation of the leaf disc by the latter. Moreover, the presence of endophytes prior to the arrival of H. vastatrix ameliorated the severity of CLR. Our work highlights both the importance of characterising the hidden biodiversity of endophytes and investigating their potential roles in the plant-endophyte interaction.

Identification and Genetic Diversity Analysis of the Pathogen of Anthracnose of Pepper in Guizhou

Anthracnose of pepper is a significant disease caused by Colletotrichum spp. In 2017 and 2021, 296 isolates were obtained from 69 disease samples. Through morphological analysis, pathogenicity detection, and polygenic phylogenetic analysis, the above strains were attributed to 10 species: C. scovillei, C. fructicola, C. karstii, C. truncatum, C. gloeosporioides, C. kahawae, C. boninense, C. nymphaeae, C. plurivorum, and C. nigrum. C. scovillei had the most strains (150), accounting for 51.02% of the total isolates; C. fructicola came in second (72 isolates), accounting for 24.49%. Regarding regional distribution, Zunyi City has the highest concentration of strains-92 strains total, or 34.18%-across seven species. Notably, this investigation showed that C. nymphaeae infected pepper fruit for the first time in China. Genetic diversity analysis showed that C. fructicola could be divided into seven haplotypes, and the population in each region had apparent genetic differentiation. However, the genetic distance between each population was not significantly related to geographical distance. Neutral detection and nucleotide mismatch analysis showed that C. fructicola might have undergone population expansion.

Identification and Fungicide Screening of Fungal Species Associated with Walnut Anthracnose in Shaanxi and Liaoning Provinces, China

Walnut is cultivated around the world for its precious woody nut and edible oil. Recently, walnut infected by Colletotrichum spp. resulted in a great yield and quality loss. In August and September 2014, walnut fruits with anthracnose were sampled from two commercial orchards in Shaanxi and Liaoning provinces, and five representative isolates were used in this study. To identify the pathogen properly, four genes per region (internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase, actin, and chitin synthase) were sequenced and used in phylogenetic studies. Based on multilocus phylogenetic analysis, five isolates clustered with Colletotrichum fioriniae, including its ex-type, with 100% bootstrap support. The results of multilocus phylogenetic analyses, morphology, and pathogenicity confirmed that C. fioriniae was one of the walnut anthracnose pathogens in China. All 13 fungicides tested inhibited mycelial growth and spore germination. Flusilazole, fluazinam, prochloraz, and pyraclostrobin showed the strongest suppressive effects on the mycelial growth than the others, the average EC50 values ranged from 0.09 to 0.40 μg/ml, and there was not any significant difference (P < 0.05). Pyraclostrobin, thiram, and azoxystrobin were the most effective fungicides on spore germination (P < 0.05), and the EC50 values ranged from 0.01 to 0.44 μg/ml. Pyraclostrobin, azoxystrobin, fluazinam, flusilazole, mancozeb, thiram, and prochloraz exhibited a good control effect on walnut anthracnose caused by C. fioriniae, and preventive activities were greater than curative activities. Pyraclostrobin at 250 a.i. μg/ml and fluazinam at 500 a.i. μg/ml provided the highest preventive and curative efficacy, and the values ranged from 81.3 to 82.2% and from 72.9 to 73.6%, respectively. As a consequence, mancozeb and thiram could be used at the preinfection stage, and pyraclostrobin, azoxystrobin, flusilazole, fluazinam, and prochloraz could be used at the early stage for effective prevention and control of walnut anthracnose caused by C. fioriniae. The results will provide more significant instructions for controlling the disease effectively in northern China.

What's in my Pot? Six Colletotrichum Species Causing Anthracnose in Brazilian Pecan Orchards

Pecan (Carya illinoinensis) is one important exotic forest crop cultivated in South America, specifically in Brazil, Uruguay, and Argentina. However, diseases such as anthracnose, favored by high humidity conditions and high summer temperatures, make its cultivation difficult, causing important loss to pecan farmers. This study used morphological and molecular approaches to identify the Colletotrichum species causing anthracnose in pecan plantations in Southern Brazil. The isolates obtained from pecan fruits with anthracnose symptoms were grouped through quantitative morphological characteristics into three distinct morphotypes. Molecular analysis of nuclear genes allowed the identification of six species of Colletotrichum causing anthracnose in pecan: C. nymphaeae, C. fioriniae, C. gloeosporioides, C. siamense, C. kahawae, and C. karsti. Three of these species are reported for the first time as causal agents of anthracnose in pecan. Therefore, these results provide an important basis for the adoption and/or development of anthracnose management strategies in pecan orchards cultivated in southern Brazil and neighboring countries.

Fungal Endophytes: Discovering What Lies within Some of Canada's Oldest and Most Resilient Grapevines

Plant diseases and pests reduce crop yields, accounting for global crop losses of 30% to 50%. In conventional agricultural production systems, these losses are typically controlled by applying chemical pesticides. However, public pressure is mounting to curtail agrochemical use. In this context, employing beneficial endophytic microorganisms is an increasingly attractive alternative to the use of conventional chemical pesticides in agriculture. A multitude of fungal endophytes are naturally present in plants, producing enzymes, small peptides, and secondary metabolites due to their bioactivity, which can protect hosts from pathogens, pests, and abiotic stresses. The use of beneficial endophytic microorganisms in agriculture is an increasingly attractive alternative to conventional pesticides. The aim of this study was to characterize fungal endophytes isolated from apparently healthy, feral wine grapes in eastern Canada that have grown without agrochemical inputs for decades. Host plants ranged from unknown seedlings to long-lost cultivars not widely propagated since the 1800s. HPLC-MS was used to identify unique endophyte-derived chemical compounds in the host plants, while dual-culture competition assays showed a range in endophytes' ability to suppress the mycelial growth of Botrytis, which is typically controlled in viticulture with pesticides. Twelve of the most promising fungal endophytes isolated were identified using multilocus sequencing and morphology, while DNA barcoding was employed to identify some of their host vines. These fungal endophyte isolates, which consisted of both known and putative novel strains, belonged to seven genera in six families and five orders of Ascomycota. Exploring the fungal endophytes in these specimens may yield clues to the vines' survival and lead to the discovery of novel biocontrol agents.

Genome evolution and transcriptome plasticity is associated with adaptation to monocot and dicot plants in Colletotrichum fungi

BACKGROUND

Colletotrichum fungi infect a wide diversity of monocot and dicot hosts, causing diseases on almost all economically important plants worldwide. Colletotrichum is also a suitable model for studying gene family evolution on a fine scale to uncover events in the genome associated with biological changes.

RESULTS

Here we present the genome sequences of 30 Colletotrichum species covering the diversity within the genus. Evolutionary analyses revealed that the Colletotrichum ancestor diverged in the late Cretaceous in parallel with the diversification of flowering plants. We provide evidence of independent host jumps from dicots to monocots during the evolution of Colletotrichum, coinciding with a progressive shrinking of the plant cell wall degradative arsenal and expansions in lineage-specific gene families. Comparative transcriptomics of 4 species adapted to different hosts revealed similarity in gene content but high diversity in the modulation of their transcription profiles on different plant substrates. Combining genomics and transcriptomics, we identified a set of core genes such as specific transcription factors, putatively involved in plant cell wall degradation.

CONCLUSIONS

These results indicate that the ancestral Colletotrichum were associated with dicot plants and certain branches progressively adapted to different monocot hosts, reshaping the gene content and its regulation.

Blueberry floral probiotics: nectar microbes inhibit the growth of Colletotrichum pathogens

AIMS

To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and threatens yields, and to assess the impacts of floral microbes and Colletotrichum pathogens on artificial nectar sugars and honey bee consumption.

METHODS AND RESULTS

The growth inhibition of Colletotrichum (Colletotrichum acutatum, Colletotrichum fioriniae, and Colletotrichum gloeosporioides) was screened using both artificial nectar co-culture and dual culture plate assays. All candidate nectar microbes were screened for antagonism against a single C. acutatum isolate. Then, the top four candidate nectar microbes showing the strongest inhibition of C. acutatum (Neokomagataea thailandica, Neokomagataea tanensis, Metschnikowia rancensis, and Symmetrospora symmetrica) were evaluated for antagonism against three additional C. acutatum isolates, and single isolates of both C. fioriniae and C. gloeosporioides. In artificial nectar assays, single and three-species cultures inhibited the growth of two of four C. acutatum isolates by ca. 60%, but growth of other Colletotrichum species was not affected. In dual culture plate assays, inhibition was observed for all Colletotrichum species for at least three of four selected microbial antagonists (13%‒53%). Neither honey bee consumption of nectar nor nectar sugar concentrations were affected by any microbe or pathogen tested.

CONCLUSIONS

Selected floral microbes inhibited growth of all Colletotrichum species in vitro, although the degree of inhibition was specific to the assay and pathogen examined. In all microbial treatments, nectar sugars were preserved, and honey bee preference was not affected.

Blueberries infected with the fungal pathogen Colletotrichum fioriniae release odors that repel Drosophila suzukii

BACKGROUND

Spotted-wing drosophila, Drosophila suzukii, is a serious pest of thin-skinned fruits. Alternative methods to control this pest are needed to reduce insecticide use, including new repellents. Previous research demonstrated that D. suzukii adults use odor cues to avoid blueberries infected with the fungal pathogen Colletotrichum fioriniae, which causes the disease anthracnose. To identify novel D. suzukii repellents, we investigated the volatile emission from experimentally-infected fruit, which were inoculated with C. fioriniae isolates in the laboratory, and from field-collected fruit, which were naturally infected and harvested from a field. We then tested the pathogen-induced volatiles on D. suzukii adult behavior.

RESULTS

Volatile emission was similar between all five C. fioriniae strains, with good agreement between experimentally-infected and field-collected berries. In total, 14 volatiles were found to be more abundant in infected versus uninfected fruit headspace. In multiple-choice bioassays, nine of the 14 volatiles elicited repellency responses from adult D. suzukii. These nine volatiles were further evaluated in dual choice assays, where all nine reduced fly capture by 43-96% compared to the control. The most repellent compounds tested were the esters ethyl butanoate and ethyl (E)-but-2-enoate, which were more or equally repellent to the known D. suzukii repellents 1-octen-3-ol, geosmin, and 2-pentylfuran. Dose-response assays identified concentration-dependent effects on D. suzukii repellency and oviposition when applied individually and consistent aversion observed across doses of a 1:1 blend.

CONCLUSION

We report two repellents from C. fioriniae-infected blueberries that could be useful semiochemicals for the behavioral manipulation of D. suzukii in the field. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Epidemiological Relevance of Colletotrichum Species Isolated from Glomerella Leaf Spot Causing Symptoms in Apple Fruit

Colletotrichum isolates from apple leaves with symptoms of Glomerella leaf spot (GLS) can cause fruit rot and several small lesion spots, here called Colletotrichum fruit spot (CFS). This work investigated the epidemiological relevance of Colletotrichum species obtained from leaves with GLS in causing diseases in immature apple fruit by comparing different fruit sizes (phenological stages) for symptom development. In the first experiment, five Colletotrichum species were inoculated in 'Gala' (Ø = 5.5 cm) and 'Eva' (Ø = 4.8 cm) fruit in the field (2016/17 season). Subsequently, C. chrysophilum and C. nymphaeae were inoculated in fruit of different sizes (Ø = 2.4 to 6.3 cm) in the field (2017/18 and 2021/22 seasons) and in the laboratory according to the phenological stages of growing fruit. At harvest of the immature inoculated fruit in the field, only CFS symptoms were observed in both cultivars. For Gala, the CFS incidence reached 50% regardless of season, pathogen species, and fruit size. For Eva, CFS symptoms were observed after inoculation with C. melonis in the 2016/17 season and in smaller fruit inoculated with C. chrysophilum and C. nymphaeae in 2021/22. During postharvest, bitter rot symptoms developed, but did not seem to come from CFS symptoms. It can be concluded that the Gala cultivar has a high susceptibility to CFS caused by the two Colletotrichum species of the greatest epidemiological importance for GLS in Brazil in all fruit sizes tested.

New Insights in the Detection and Management of Anthracnose Diseases in Strawberries

Anthracnose diseases, caused by Colletotrichum spp., are considered to be among the most destructive diseases that have a significant impact on the global production of strawberries. These diseases alone can cause up to 70% yield loss in North America. Colletotrichum spp. causes several disease symptoms on strawberry plants, including root, fruit, and crown rot, lesions on petioles and runners, and irregular black spots on the leaf. In many cases, a lower level of infection on foliage remains non-symptomatic (quiescent), posing a challenge to growers as these plants can be a significant source of inoculum for the fruiting field. Reliable detection methods for quiescent infection should play an important role in preventing infected plants' entry into the production system or guiding growers to take appropriate preventative measures to control the disease. This review aims to examine both conventional and emerging approaches for detecting anthracnose disease in the early stages of the disease cycle, with a focus on newly emerging techniques such as remote sensing, especially using unmanned aerial vehicles (UAV) equipped with multispectral sensors. Further, we focused on the acutatum species complex, including the latest taxonomy, the complex life cycle, and the epidemiology of the disease. Additionally, we highlighted the extensive spectrum of management techniques against anthracnose diseases on strawberries and their challenges, with a special focus on new emerging sustainable management techniques that can be utilized in organic strawberry systems.

A Bitter, Complex Problem: Causal Colletotrichum Species in Virginia Orchards and Apple Fruit Susceptibility

Bitter rot, caused by Colletotrichum species, is one of the most devastating summer rot diseases affecting apple production in the Eastern United States. Given the differences in virulence and fungicide sensitivity levels between organisms belonging to the acutatum species complex (CASC) and the gloeosporioides species complex (CGSC), monitoring their diversity, geographic distribution, and frequency are essential for successful bitter rot management. In a 662-isolate collection from apple orchards in Virginia, isolates from CGSC were dominant (65.5%) in comparison to the CASC (34.5%). In a subsample of 82 representative isolates, using morphological and multilocus phylogenetic analyses, we identified C. fructicola (26.2%), C. chrysophilum (15.6%), C. siamense (0.8%), and C. theobromicola (0.8%) from CGSC and C. fioriniae (22.1%) and C. nymphaeae (1.6%) from CASC. The dominant species were C. fructicola, followed by C. fioriniae and C. chrysophilum. C. siamense followed by C. theobromicola developed the largest and deepest rot lesions on Honeycrisp fruit in our virulence tests. Detached fruit of nine apple cultivars and one wild accession (Malus sylvestris) were harvested early and late season and tested in controlled conditions for their susceptibility to C. fioriniae and C. chrysophilum. All cultivars were susceptible to both representative bitter rot species, with Honeycrisp fruit being the most susceptible and M. sylvestris, accession PI 369855, being the most resistant. We demonstrate that the frequency and prevalence of species in Colletotrichum complexes are highly variable in the Mid-Atlantic and provide region-specific data on apple cultivar susceptibility. Our findings are necessary for the successful management of bitter rot as an emerging and persistent problem in apple production both pre- and postharvest.

Characterization of Colletotrichum Causing Anthracnose on Rubber Trees in Yunnan: Two New Records and Two New Species from China

Among the most damaging diseases of rubber trees is anthracnose caused by the genus Colletotrichum, which leads to significant economic losses. Nonetheless, the specific Colletotrichum spp. that infect rubber trees in Yunnan Province, an important natural rubber base in China, have not been extensively investigated. Here, we isolated 118 Colletotrichum strains from rubber tree leaves exhibiting anthracnose symptoms in multiple plantations in Yunnan. Based on comparisons of their phenotypic characteristics and internal transcribed spacer ribosomal DNA sequences, 80 representative strains were chosen for additional phylogenetic analysis based on eight loci (act, ApMat, cal, CHS-1, GAPDH, GS, his3, and tub2), and nine species were identified. Colletotrichum fructicola, C. siamense, and C. wanningense were found to be the dominant pathogens causing rubber tree anthracnose in Yunnan. C. karstii was common, whereas C. bannaense, C. brevisporum, C. jinpingense, C. mengdingense, and C. plurivorum were rare. Among these nine species, C. brevisporum and C. plurivorum are reported for the first time in China, and two species are new to the world: C. mengdingense sp. nov. in the C. acutatum species complex and C. jinpingense sp. nov. in the C. gloeosporioides species complex. Their pathogenicity was confirmed with Koch's postulates by inoculating each species in vivo on rubber tree leaves. This study clarifies the geographic distribution of Colletotrichum spp. associated with anthracnose on rubber trees in representative locations of Yunnan, which is crucial for the implementation of quarantine measures.

The Role of Fatty Acids from Plant Surfaces in the Infectivity of Colletotrichum fioriniae

Aqueous extracts derived from flowers stimulate germination, secondary conidiation, and appressorial formation of various latent fruit rotting fungi. Even raindrops passing over flowers accumulate sufficient activity to influence the infectivity of fruit rotting fungi. Using a spore germination bioassay, high levels of bioactivity were found in chloroform extracts from plant tissues, implicating the nonpolar components of the cuticle. The fatty acid (FA) and fatty acid methyl ester (FAME) composition (C9-C20) of blueberry and cranberry tissues as well as aqueous flower extracts were characterized using a gas chromatography-mass spectrometry (GC-MS) method. The FAs and FAMEs found in the plant extracts were then tested for bioactivity using a spore germination bioassay. The C16:0 and C18:2 FAs and FAMEs, as well as the C18:0 FAME and the C20:0 FA, all stimulated appressorial formation while the C10:0 FA stimulated secondary conidiation. The C10:0 and C16:0 FAs were the only two bioactive components also identified from the aqueous floral extracts of both blueberry and cranberry and are therefore considered as contributors to the bioactivity observed in these extracts. The aqueous extracts from surfaces other than flowers showed little or no activity, and it is speculated that the movement of FAs may be related to the level of polymerization and cutin polyester development in flowers versus other plant organs. This study highlights the importance of the bloom period for infection and that the apparent effects on host susceptibility may therefore depend on the availability of specific FAs or combinations thereof.

Two new species of Colletotrichum (Glomerellaceae, Glomerellales) causing walnut anthracnose in Beijing

Colletotrichum species are plant pathogens, saprobes and endophytes on various plant hosts. It is regarded as one of the 10 most important genera of plant pathogens in the world. Walnut anthracnose is one of the most severe diseases affecting walnut productivity and quality in China. In this study, 162 isolates were obtained from 30 fruits and 65 leaf samples of walnut collected in Beijing, China. Based on morphological characteristics and DNA sequence analyses of the concatenated loci, namely internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), chitin synthase 1 (CHS-1) and beta-tubulin (TUB2), these isolates were identified as two novel species of Colletotrichum, i.e. C.juglandicola and C.peakense. Koch's postulates indicated that both C.juglandicola and C.peakense could cause anthracnose in walnut.

The evolution of mini-chromosomes in the fungal genus Colletotrichum

Anthracnose diseases caused by Colletotrichum species are among the most common fungal diseases. These symptoms typically manifest as dark, sunken lesions on leaves, stems, and fruit. In China, mango anthracnose seriously affects fruit yield and quality. Genome sequencing of several species shows the presence of mini-chromosomes. These are thought to contribute to virulence, but their formation and activity remain to be fully elucidated. Here, we assembled 17 Colletotrichum genomes (16 isolated from mango plus one from persimmon) through PacBio long-read sequencing. Half of the assembled scaffolds had telomeric repeats at both ends indicating full-length chromosomes. Based on comparative genomics analysis at interspecies and intraspecies levels, we identified extensive chromosomal rearrangements events. We analyzed mini-chromosomes of Colletotrichum spp. and found large variation among close relatives. In C. fructicola, homology between core chromosomes and mini-chromosomes suggested that some mini-chromosomes were generated by recombination of core chromosomes. In C. musae GZ23-3, we found 26 horizontally transferred genes arranged in clusters on mini-chromosomes. In C. asianum FJ11-1, several potential pathogenesis-related genes on mini-chromosomes were upregulated, especially in strains with highly pathogenic phenotypes. Mutants of these upregulated genes showed obvious defects in virulence. Our findings provide insights into the evolution and potential relationships to virulence associated with mini-chromosomes. IMPORTANCE Colletotrichum is a cosmopolitan fungal genus that seriously affects fruit yield and quality of many plant species. Mini-chromosomes have been found to be related to virulence in Colletotrichum. Further examination of mini-chromosomes can help us elucidate some pathogenic mechanisms of Colletotrichum. In this study, we generated novel assemblies of several Colletotrichum strains. Comparative genomic analyses within and between Colletotrichum species were conducted. We then identified mini-chromosomes in our sequenced strains systematically. The characteristics and generation of mini-chromosomes were investigated. Transcriptome analysis and gene knockout revealed pathogenesis-related genes located on mini-chromosomes of C. asianum FJ11-1. This study represents the most comprehensive investigation of chromosome evolution and potential pathogenicity of mini-chromosomes in the Colletotrichum genus.

Mango anthracnose disease: the current situation and direction for future research

Mango anthracnose disease (MAD) is a destructive disease of mangoes, with estimated yield losses of up to 100% in unmanaged plantations. Several strains that constitute Colletotrichum complexes are implicated in MAD worldwide. All mangoes grown for commercial purposes are susceptible, and a resistant cultivar for all strains is not presently available on the market. The infection can widely spread before being detected since the disease is invincible until after a protracted latent period. The detection of multiple strains of the pathogen in Mexico, Brazil, and China has prompted a significant increase in research on the disease. Synthetic pesticide application is the primary management technique used to manage the disease. However, newly observed declines in anthracnose susceptibility to many fungicides highlight the need for more environmentally friendly approaches. Recent progress in understanding the host range, molecular and phenotypic characterization, and susceptibility of the disease in several mango cultivars is discussed in this review. It provides updates on the mode of transmission, infection biology and contemporary management strategies. We suggest an integrated and ecologically sound approach to managing MAD.