Abstract:
Objective To identify the pathogenic fungi of pepper anthracnose and screen the fungicides with strong inhibitory effects.
Method The typical leaves and fruits with anthracnose symptoms were collected from the peppers named ‘Dangwu’ in Huaxi, Guiyang, Guizhou. The pathogen was isolated. Its pathogenicity and classification were determined by monospore isolation, Koch’s postulates, and morphological characteristics combined with multi-locus (ITS, ACT, GAPDH andCHS-1) phylogenetic analysis. The sensitivities of pathogen to six chemical fungicides and six biological fungicides were investigated by the mycelial growth rate method.
Result The pathogen causing pepper ‘Dangwu’ anthracnose in Huaxi was identified as Colletotrichum scovillei. The indoor fungicide sensitivity test showed that 12 fungicides all had certain inhibitory effect against C. scovillei. The inhibition effects of 75%(w) trifloxystrobin·tebuconazole WDG, 10%(w) difenoconazole WDG and 250 g/L pyraclostrobin SC were higher with the EC50 of 0.254, 0.731 and 0.745 mg/L, respectively, followed by 200 g/L allylisothiocyanate SL, 3% (w) zhongshengmycin WP, 10 g/L phenazine-1-carboxylic acid SC, 80 g/L ningnanmycin AS, 200 g/L allylisothiocyanate EW and 10 g/L osthol ME with the EC50 of 1.238, 1.307, 1.711, 2.929, 3.175 and 2.191 mg/L, respectively. 10% (w) difenoconazole WDG and 250 g/L pyraclostrobin SC mixed at the volume ratio of 1∶4 or 2∶3 showed an obvious synergistic effect on inhibiting the pathogen based on the joint toxicity test and evaluation results.
Conclusion This study can provide references for the field prevention and control of pepper anthracnose using pesticides.
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