Evaluation of plant extracts for the control of powdery mildew disease in coriander (Coriandrum sativum L.)

摘要

Coriander is one of the important culinary spice crops grown for its green leaves and seeds. In Tamil Nadu it is grown in Thoothugudi, Tiruchirappalli, Cuddalore, Perambalur, Tirunelveli, Ramanathapuram, Virudhunagar and Coimbatore districts in an area of 36,383 hectares with an annual production of 11,200 t. The crop is prone to attack by several diseases. Among them, powdery mildew disease caused by Erysipghe polygoni is very serious and destroys the crop completely if allowed unchecked in the initial stages. Srivastava et al. (8) reported the occurrence of powdery mildew in coriander. A severe occurrence of powdery mildew was noticed in 1983 in Coimbatore by Vinayagamoorthy et al. (9). Application of fungicide on coriander leaves to control powdery mildew causes direct effect to human health since aromatic tender leaves of coriander are used almost every day in Indian cuisine. Therefore, to alleviate all these ill effects, environmentally safe long lasting and eco friendly biological are the need of the day and the future is plant disease management. Biocontrol methods using eco-friendly fungi toxicant from higher plants (plant extracts / seed extract) gained greater importance now-a-days because of the fungitoxicants from higher plants have low phytotoxicity, easy bio degradability and stimulation in host metabolism (Fawcetti and Spencer (3), Bege (1). Green plants appear to be good reservoirs of effective therapeutant and would constitute an inexhaustible source of harmless pesticides (Shragio, (7).