Author : Corey, Frederick M. Jr.

Summary : The ecology and economic injury levels (EIL) of Idioscopus clypealis (Leth.) were studied from May 1984 to June 1986 in Central Visayas. This pest was found to be the most destructive species of mango leafhoppers. Under natural condition (untreated), the population fluctuation of the pest was influenced by the stage of panicle development while under different insecticide pressure, it was more affected by the efficacy and frequency of insecticide application. The treatment decision lines for sequential sampling on leafhoppers are : d = 1.820n+- 2.6801. Some preying mantis and four species of spiders fed on the nymphs of I. clypealis. The most attractive light to adult I. clypealis was natural color. Its attractiveness increased with the increase in wick size especially during dark nights. Leafhoppers reduced the yield of mango. The panicles were found to be susceptible to infestation at all stages of development. Using multiple linear regression equation. Based on statistical and economic analyses, cyfluthrin is recommended to control leafhoppers. This insecticide offered the highest net benefit and marginal rate of return (MRR) ranging from 157 to 230 percent in two croppings. Permethrin + piperonyl butoxide may also be used since its MRR was above 40 percent. Such consideration is valuable to the farmers, managers and industry.