Comparative studies on the effect of benomyl on growth and ultrastructureof two isolates ofphytophthorainfestansfrom Egypt

Abstract

The effect of benomyl as a fungicide on the growth rate and ultrastructure of two isolates (P623 and P1319) of Phytophthora infestans is compared. Using different concentrations (50, 100, 200 and 500 ppm) of benomyl caused an inhibition of the mycelial growth of both isolates depending on the degree of concentration. The isolate P1319 was found to be more sensitive to benomyl than the isolate P623. Ultrastructural studies confirmed these observations. The hyphae of isolate P1319 subjected to 100 and 500 ppm benomyl showed severe changes in the cytoplasm more than isolate P623. The increase of lipid bodies and vacuoles in hyphal cytoplasm of both isolates was the characteristic phenomenon after treatment of benomyl particularly at the concentration of 500 ppm.