Survey of the Incidence and Severity of Bhendi (Abelmoschus esculentus (L.) Moench.) and Peas (Pisum sativum L.) Powdery Mildew Diseases in Tamil Nadu, India

Field survey of two important vegetable crop plants viz., bhendi and peas were conducted in 5 different districts of Tamil Nadu revealed that the Per cent Disease Index (PDI) of bhendi powdery mildew ranged from 43.32–90.13. Alanthurai of Coimbatore district recorded highest disease incidence (90.13), followed by Ottanchatharam of Dindugal district (86.92) and Narasipuram of Coimbatore district (80.62). The minimum of 43.32 per cent was recorded in Pettai village of Karaikal region. Field surveys were conducted in 10 villages of Nilgiris district in Tamil Nadu revealed that the disease incidence of pea powdery mildew ranged from 51.00 to 70.19 per cent. Thummanatty village recorded the least incidence 51.00 per cent as compared to highest incidence 70.19 per cent in Bingigal village of Nilgiris district. The bhendi powdery mildew disease produce symptoms on the upper surface of the leaves as small, round, whitish or yellow spots on leaves and sometimes stems. The disease is found mainly on the older leaves and stems of plants and leads to premature defoliation. In case of, pea powdery mildew disease symptoms a white “powdery ” spot on the lower leaves and stems. Wet or heavy dew conditions help to spread the disease to upper leaves, flowers and pods. Infected plants stay green while healthy plants mature and ripen normally and heavy reduction in pod formation due to severe infection. The pathogenicity tests conducted for E. cichoracearum and E. pisi resulted in the development of typical symptoms of the powdery mildew diseases.