Search

[Objectives] The paper was to study molecular characterization, morphology and pathogenicity of Curvularia pseudobrachyspora, a new causal agent of leaf spot on banana. [Methods] Banana (Musa acuminate') leaves with streaks or long ellipse-shaped lesions were sampled in an orchard of Danzhou City, Hainan Province, China in 2021. Fungus isolates were isolated from the diseased tissues and further identified as C. pseudobrachyspora based on morphological characteristics of colony, conidiophore and spore, phylogenetic analyses of the ITS region, GAP DP and TET-la genes. [Results] In the pathogenicity test, the fungus re-isolated from inoculated leaves with necrotic lesions was identified morphologically and molecularly, fulfilling Koch's postulates. [Conclusions] C. pseudobrachyspora is a new pathogen causing leaf spot of banana in China and the world. [ABSTRACT FROM AUTHOR]

[Objectives] The paper was to identify the causal agent of leaf spot of banana in Hainnan, China. [Methods] Fungus isolates were isolated from the diseased tissues, and morphological characteristics of colony and spore were observed. Furthermore, phylogenetic analyses and pathogenicity test were conducted to confirm the pathogen. [ Results] The fungus isolates from the diseased tissues was identified as Curvularia geniculata. [Conclusions] C. geniculata is a new pathogen causing leaf spot of banana in Hainan, China. This finding will help to broaden the distribution and host range of C. geniculata, indicating that it poses potential damage to banana in China. [ABSTRACT FROM AUTHOR]

[Objectives] The paper was to identify Alternaría alternata causing leaf spot disease on Huangdi banana in China. [Methods] Fungal isolates were isolated and identified by morphological features, molecular identification and pathogenicity test. [Results] There were light to dark brown, tiny oval spots on leaves. The causal agent isolated from affected leaves was identified as A. alternata based on the morphological properties, coupled with sequence analyses of the internal transcribed spacer (IIS) region, large subunit ribosomal DNA (LSU rD-NA) and the translation elongation factor 1-alpha (TEF-la) gene. Koch's postulates were fuEilled by successful re-isolation of pathogen from the artificial inoculated leaves. [ Conclusions] To our knowledge, this is the first report of leaf spot caused by A. alternata on Huangdi banana in China. The identification of A. alternata as the causal agent of the observed leaf spot disease on Huangdi banana is critical to the prevention and control of this disease in the future. [ABSTRACT FROM AUTHOR]

[Objective] This study aimed to develop a PCR assay for detecting Xanthomonas campestris pv. mangiferaeindicae (Xcm) in culture and in planta. [Method] Primers (XcmHF and XcmHR) were designed based on the partial sequence of hrpB gene from xanthomonads to develop a PCR assay for Xcm. Furthermore, specificity and sensitivity of the primer pairs were analyzed in detection of genomic DNA and cell from Xcm. [Result] Amplication was positive only with genomic DNA from positive control ATCC11637 and 12 Xcm strains; no PCR products were amplified with genomic DNA from ten other xanthomonads and seven other bacterial species. The sensitivity of detection was 2.4 pg/μl genomic DNA, and 1.8 × 104 CFU/ml cells. The primers also worked well for pathogen detection in direct PCR assays of Xcm colonies grown on liquid medium and in PCR assays of total DNA from leaf, branch and fruit lesions. [Conclusion] A PCR assay was successfully established for rapid detection of Xcm in culture and in planta. [ABSTRACT FROM AUTHOR]

[Objectives] The study was to confirm the etiological agent of leaf spot on banana in Yunnan Province of China. [Methods] Fungus isolates were isolated from the diseased tissues, and cultured to observe the morphological characteristics of colony and spore. Furthermore, phylogenetic analyses and pathogenicity test were also conducted to confirm the pathogen. [Results] The fungus isolated from the diseased tissues was identified as Neopestalotiopsis clavispora. [Conclusions] N. clavispora is a new pathogen causing leaf spot of banana. This research provides the first description of N. clavispora as a causal agent on banana in China, and adds new insights related to the host range of N. clavispora. [ABSTRACT FROM AUTHOR]

[Objective] The paper was to screen effective fungicides to control Cordana leaf spot caused by Neocordana musae. [Method] The toxicities of six fungicides against mycelial growth of N. musae were measured by the method of mycelium growth inhibition. [Result] The average EC50 values of six fungicides against mycelial growth ranged from 0.102 9 to 504.065 µg/mL. Among them, 22.5% picoxystrobin SC and 12.5% epoxiconazole SC showed strong inhibitors' activity on mycelial growth, with the average EC% values of 0.102 9 and 0.685 1 µg/mL, respectively; followed by 50% thiophanate-methyl SC, with an average EC50 value of 1.993. 80% Azoxystrobin WG showed a relatively low sensitivity against N. musae, with an average EC50 value of 504.046. [Conclusion] The six fungicides tested have great value in preventing and controlling Cordana leaf spot. 22.5% Picoxystrobin SC, 12.5% epoxiconazole SC and 50% thiophanate-methyl SC have better inhibitory activities on mycelial growth of N. musae, and can be further used in field trials. [ABSTRACT FROM AUTHOR]