| A new anthracnose disease caused by Colletotrichum acutatum was firstly discovered on chili pepper in Hunan Zhijiang in 2009. The existing fungicides on the new disease were found invalid as pointed by pepper growers. In order to screen out effective fungicides for the diseases,14 fungicides were examined for mycelium inhibition activity on C. gloeosporioides and C. acutatum in vitro. The results were as follows:In this study,12 kinds fungicides were used to toxicity test, the results showed that prochloraz, Tebuconazole and Difenoconazole had highest toxicitie on the two Colletotrichum capsici. The results showed that Prochloraz, Tebuconazole and Difenoconazole had the maximum virulence for two kinds Colletotrichum capsici.The EC50 of Colletotrichum acutatum were 0.044μg·mL-1,0.2034μg·mL-1 and 0.6236μg·mL-1 respectively; and EC50 of Colletotrichum gloeosporioides were 0.0209μg·mL-1,0.063μg·mL-1 and 0.3638μg·mL-1.Toxicity results from the determination of view, the virulence of C. acutatum and C gloeosporioides for 12 kinds fungicides is the same, namely:Prochloraz> Tebuconazole> Difenoconazole> Dichlorfluanid> Carbendazim> Folpet> Captan> Resin acid copper> Cuproxat> Chlorothalonil> Mancozeb> Thiram.Two kinds fungicides bought from the market of pharmaceutical compounding, The EC50 of Colletotrichum acutatum and Colletotrichum gloeosporioides with cream-hymexazol anthrax were 0.6236μg·mL-1 and 3.3868μg·mL-1 respectively; but the two kinds Colletotrichum capsici is not sensitive on cream·propamocarb, EC50 was 267.0275μg·mL-1 and 111.9545μg·mL-1 respectively.After fungicide compound toxicity test results showed that the synergistic factor (SR) of all mixtures against C. acutatum and C. gloeosporioides were greater than 0.5, the phenomenon does not appear antagonistic. Which prochloraz-Carbendazim (0.1: 99.9) compound after the anthrax spores on the tip and the synergistic factor of C. gloeosporioides (SR) were 8.6595 and 7.0466, showing the best synergies. Prochloraz-Difenoconazole (6.6:93.4), Tebuconazole-Difenoconazole(24.6:75.4), prochloraz-folpet (0.09:99.91) and Prochloraz-A Cream·hymexazol (0.7:99.3) mixture of anthrax spores on the tip also showed synergism. Prochloraz-Folpet (0.09: 99.91) and Prochloraz-A cream·hymexazol (0.7:99.3) mixtures against C. gloeosporioides also showed synergism. While all other combinations showed additive pharmaceutical effect.C. gloeosporioides are more sensitive than C. acutatum. That is, C. acutatum on same fungicide or mixture with more tolerance.Pharmaceutical compound under the same concentrations in vitro inhibition of pepper fruit were lower than on the plate mycelial inhibition. Which mixture of five pharmaceutical prochloraz·Captan(0.09:99.91), prochloraz·folpet(0.09:99.91), prochloraz·Carbendazim(0.1:99.9), prochloraz·Dichlorfluanid(0.2:99.8) and Tebuconazole·Difenoconazole(24.6:75.4) showed effective effect, the control effect was 72%,56%,55%,54% and 53.33% respectively. However, the high concentration compound fungicide control effect in vitro performance is Not significantly increase. |
