Taxonomy, Biological Characterization, and Fungicide Sensitivity of a New Species, Cladobotryum hypsigum, Causing Cobweb Disease in Gold Mushroom (Pholiota conissans) in China.
In vitro fungicide sensitivity assays, performed using the hyphal growth inhibition method against six common fungicides, demonstrated that Carbendazim was the most effective agent, indicating significant selectivity.
Abstract
Pholiota conissans is an economically important edible mushroom in China; however, its production has been severely impacted by cobweb disease during the fruiting stage, leading to substantial yield losses. In this study, a fungal pathogen was identified as the causal agent of cobweb disease. The strains were isolated from infected fruiting bodies collected in November 2021 and were identified as a new species Cladobotryum hypsigum sp. nov., based on morphological characteristics and a multi-locus phylogenetic analysis of four gene regions (ITS, RPB1, RPB2, and TEF). Pathogenicity tests were conducted by inoculating healthy mushrooms with a spore suspension of representative isolates. The resulting symptoms were consistent with those observed in cultivation settings, and the same pathogen was successfully re-isolated, thus fulfilling Koch's postulates. Biological characterization indicated that the optimal conditions for mycelial growth were a temperature of 25°C and pH 5. Sucrose and yeast extract were the most suitable carbon and nitrogen sources, respectively. In vitro fungicide sensitivity assays, performed using the hyphal growth inhibition method against six common fungicides, demonstrated that Carbendazim was the most effective agent. The IC50 values for Carbendazim were 0.7742 µg/mL for the pathogen and 4.827 µg/mL for the host mushroom, indicating significant selectivity. These findings provide a scientific basis for developing effective strategies to manage cobweb disease in P. conissans cultivation.
The brown planthopper, Nilaparvata lugens, is a major rice pest causing significant yield losses across Asia. Concerns over the environmental, health, and resistance-related impacts of current chemical control strategies highlight the need for sustainable alternatives. In this study, we isolated and characterized a novel entomopathogenic fungus, strain NLS-1, from mycosed N. lugens cadavers. Based on morphological observations and internal transcribed spacer (ITS) sequence analysis, strain NLS-1 was assigned to Aspergillus section Flavi and designated as Aspergillus sp. NLS-1. Bioassays revealed that the isolate exhibited high virulence against third-instar N. lugens nymphs; the highest concentration of 1 × 108 conidia/mL resulted in 97.22% corrected mortality by 9 days post-inoculation and a median lethal time (LT50) of 4.13 days. Scanning electron microscopy delineated the infection process, confirming firm conidial adhesion to the cuticle, followed by germination, hyphal proliferation, and eventual host colonization. Furthermore, fungal infection significantly altered the nymphs' bacterial community structure, notably affecting the relative abundances of Acinetobacter and Serratia. These findings position Aspergillus sp. NLS-1 as a promising biocontrol agent and suggest that its pathogenicity may be mediated through the disruption of the host's microbiota, providing new insights for the integrated management of N. lugens.
H. Niu, Sai-Ge Sun, Zhi-Chun Zhang et al.· Journal of Invertebrate Path...· 0 citations
The findings provide a theoretical foundation for accurate disease diagnosis, epidemiological surveillance, and the development of effective chemical control strategies for rubber plantations.
Zhiying Cai, Lili He, Li-Ming Dai et al.· Plants· 0 citations
Results indicate that CLSD in Viet Nam is associated with a pathogen complex in which C. siamense is more pathogenic than P. microspora, while C. siamense grew most rapidly on potato-based media at 25–30°C.
Hieu Nguyen Don, Nhan Luan Doan, Thi Kim Uyen Nguyen· CTU Journal of Innovation an...· 0 citations
Fusarium oxysporum f. sp. cubense (Foc) is a soil-borne fungal pathogen responsible for fusarium wilt, which constitutes one of the major constraints in banana cultivation. Information on the occurrence and molecular characteristics of Foc in Malang Regency, one of the banana-producing areas in East Java, Indonesia, remains limited, hindering effective disease surveillance and management. This study was conducted to isolate and characterize fungal isolates associated with fusarium wilt disease in banana plants using an integrated approach combining morphological characterization, pathogenicity testing, PCR amplification, ITS sequence analysis, and phylogenetic analysis. Three fungal isolates were recovered from symptomatic banana plants collected in Donomulyo, Malang Regency, and one representative isolate (DNM) was selected for molecular characterization based on its morphological similarity to the other isolates. Morphological observations revealed characteristics typical of Fusarium oxysporum. ITS sequence analysis showed 100% query coverage and 100% sequence identity with reference Foc sequences available in GenBank, while phylogenetic analysis clustered the DNM isolate with reference Foc isolates with 94% bootstrap support. Pathogenicity assays demonstrated that the isolate induced typical fusarium wilt symptoms, resulting in an LDI of 16.39% at 14 DAI and an RDI of 41.67% at 45 DAI. These findings provide baseline information on putative Foc isolates in Malang Regency, particularly in the Donomulyo area, and establish an integrated characterization framework to support disease surveillance, early detection, and the development of integrated management strategies for fusarium wilt in banana production systems.
Cowpea (Vigna unguiculata L.) is a major grain legume whose productivity is severely limited by soil-borne root rot pathogens. This study isolated and identified the fungi associated with cowpea root rot and evaluated their pathogenicity and extracellular enzyme production. A total of 45 fungal isolates were recovered from naturally infected cowpea roots and identified as Fusarium solani, Fusarium oxysporum, Rhizoctonia solani, and Macrophomina phaseolina. F. solani was the predominant species, accounting for 33.33% of the isolates. Morphological identification was confirmed by ITS-rDNA sequencing, and the representative F. solani isolate was deposited in GenBank under accession number LC924504. Pathogenicity assays demonstrated significant differences among the tested fungi. F. solani exhibited the greatest virulence, reducing seed germination to 20% in the Petri dish assay and causing 100% disease incidence with a mean disease severity of 79.17% under greenhouse conditions. F. oxysporum ranked second in pathogenicity, whereas R. solani and M. phaseolina were comparatively less aggressive. Enzymatic analyses revealed that F. solani produced the highest cellulase (2.08 U mL-1) and protease (5.09 U mL-1) activities, indicating a strong association between extracellular hydrolytic enzyme production and fungal virulence. The elevated enzymatic activity corresponded closely with increased disease incidence, disease severity, and reduced seed germination. Overall, the findings identify F. solani as the principal causal agent of cowpea root rot and highlight the critical role of cell wall-degrading enzymes in disease development. These results provide a basis for developing effective disease management strategies and breeding resistant cowpea cultivars.
Anthracnose is a fungal disease that severely affects mango (Mangifera indica L.) production globally. In Zimbabwe, mango production is a source of household nutrition and income from informal markets but there has been limited information on the fungal pathogens related to anthracnose in the main production areas. Lack of local baseline data limits proper diagnosis and the development of disease control measures. The main objective of this study was to morphologically characterize fungal isolates that were associated with anthracnose symptoms on mango fruits and leaves, which were collected from different orchards in the Mutoko District of Zimbabwe. Symptomatic samples from various trees were randomly collected in the different orchards. Pieces of tissue were taken from the edge of the lesions and surfaces sterilized, and were inoculation on potato dextrose agar. Colonies of the fungi that appeared were re-cultured to obtain pure culture. The isolates exhibited different colony morphology but mostly they produced grey to dark colonies of cottony to velvety textures. Based on morphology, the isolates were considered members of the Colletotrichum genus; nevertheless, species identification by molecular means was not performed. Through this research, the morphological characteristics of the anthracnose, associated Colletotrichum isolates from the Mutoko District were initially documented. This evidence calls for molecular and pathogenicity analyses to identify the species so that disease management can be effective.
Nyarai Chabikwa, Cleopas C. Chinheya, N. Mapope et al.· Journal of Tropical Plant Pr...· 0 citations
