Control effect of zineb, diffenoconazole and prochlorazmanganese against Stylosanthes anthracnose

Stylo anthracnose is one of the main diseases to damage Stylosanthes guianensis, and chemical control is still the most effective method to reduce the damage. The research result showed that the fungal colony growth and conidia germination were inhibited by Zineb (65% WP), Diffenoconazole (50% WP) and ProchlorazManganese (28% WP), in which, the inhibitory rate of colony increased with the concentration of Zineb and Diffenoconazole. After 5 days later, the inhibitory rate reached nearly 100% under the treatment of 3 concentrations of ProchlorazManganese. It reached 95.45% under 700fold diluted Zineb, and 82.13% under 10 000fold diluted Diffenoconazole. The inhibitory rate of conidia germination was positive correlation with the concentration of 3 fungicides and it reached 100% by 700fold diluted Zineb, 10 000fold diluted Diffenoconazole and 1 500fold diluted ProchlorazManganese after treatment for 12 hours. However, the inhibitory rate of conidia germination of Zineb and Diffenoconazole decreased after treatment 36 hours. The relative control effect of 3 fungicides was positive correlated with the concentration, and it was 40.20% by 500fold diluted Zineb, 36.62% by 1 000fold diluted ProchlorazManganese and 22.15% by 7 000fold diluted Diffenoconazole after treatment for 7 days. The relative control effect of fungicide in laboratory test was obviously less than that in pot experiment.