A report on two new hosts (Oxalis corniculata L. and O.corymbosa DC.) of powdery mildew fungus (Erysiphe cichoracearum DC.)

Abstract

The powdery mildew disease caused by Erysiphe cichoracearum on Oxalis corniculata and O. corymbosa was recorded for the first time from Uttar Pradesh, India. The symptoms of disease appeared in the first week of March on the upper surface of leaves and then on other green parts of the plant. The development of few cleistothecia on the upper surface of leaves was also observed in the last week of April, when conidial production was slowed down and ceased. The infected plants remained stunted due to reduction in size and number of the leaves. The effect of severe infection of E. cichoracearum on O. corniculata also led to a premature defoliation and early death of the plants. The disease severity was more on Oxalis corniculata as compared to O .corymbosa. The frequency of occurrence of disease on O. corniculata was 75.8 % as compared to 46.0 % on O. corymbosa