Effect of some management practices on the incidence of insect pests and yield of egg plant(Solanum melongenaL.) in India

The influence of four transplanting dates and three plant densities (30, 36 and 42 plants/12.8 m2) on the incidence of jassid, Amrasca biquttula biquttula Ishida, per cent fruit infestation (weight basis) by shoot and fruit borer, Leucinodes orbonalis Guen. and marketable yield of egg‐plant (Solanum melongena) was investigated under sprayed and unsprayed conditions. Early transplanted (17th July) crops resulted in increased incidence of both pests. Plant density per unit area inversely affected the jassid population. However, maximum L. orbonalis infestation was observed with highest plant density of 42 plants/12.8 m2 plot. Spraying of demetonmethyl (0.025%) significantly reduced the jassid population. Similarly, use of endosulfan (0.07%) reduced the per cent fruit infestation by borer from 25.1 (unsprayed) to 15.8 (sprayed) per cent. Greater marketable fruit yield was obtained in early and recommended transplanted crops, than in delayed transplantings. Spraying the crop with insecticides gave increased marketable fruit yields over the unsprayed crop of up to 25%.