| 【Objective】In recent years, citrus melanose has been widespread in citrus planting areas, which has
a great impact on the citrus production. This paper aims to screen out new fungicides with strong antifungal effect on the
pathogen of citrus melanose, which can provide a reference for selecting more rotating fungicides to control the disease
in the field.【Method】The pathogen was isolated from symptomatic citrus fruits collected in Guangxi and identified
based on the morphological characteristics and rDNA-ITS sequence analysis. Antifungal effects of 21 fungicides on the
pathogen were tested by mycelial growth inhibition method, and fungicides with good effects were selected to determine
their toxicity to the pathogen.【Result】Three strains with morphological characteristics of Diaporthe citri were isolated
from the diseased fruits, and the homology of rDNA-ITS sequence of the strain and that of D. citri in GenBank was
99%, therefore, the pathogen of citrus melanose in Guangxi was identified as D. citri, Pyraclostrobin·cuppric nonyl
phenolsulfonate, epoxiconazole·thifluzamide, copper quinolate·pyraclostrobin, epoxiconazole·pyraclostrobin and picoxystrobin
were selected from 21 kinds of fungicides for toxicity test. The EC50 values of five fungicides were 0.106 μg/mL, 0.814 μg/mL,
0.064 μg/mL, 0.053 μg/mL and 0.056 μg/mL, respectively, and fepoxiconazole·pyraclostrobin had the highesttoxicity to D. citri. 【Conclusion】Pyraclostrobin·cuppric nonyl phenolsulfonate, epoxiconazole·thifluzamide, copper
quinolate·pyraclostrobin, epoxiconazole·pyraclostrobin and picoxystrobin had strong inhibitory effect on D. citri. |
