Author : Villamayor, Federico G, Jr.

Summary : The effect of insecticides (Temik 10 G and Azodrin), species diversity (cotton alone, cotton with mulch, cotton with peanut, cotton with weeds) and nitrogen fertilizer in the form of ammonium sulfate on insect infestations and yields of cotton were studied. The experiment was conducted at the Central Experiment Station, UPLB, College, Laguna from January 1975 to May 1975, using the split-split plot as the experimental design. The results showed that Temik was good only against the sucking insects for nine weeks, but is also made the plants more susceptible to the chewing insects as a result of habitat differentiation between the aphids and the larvae. Azodrin, on the other hand, was effective against the chewing insects only for a week. therew as a faster resurgence of the larvae on sprayed plots especially at higher concentration. In addition, Azodrin treated plots exhibited greater vegetative growth hence, a lower-seed cotton yield. Increasing species diversity did not diminish insect infestation. High seed cotton yields were obtained with mulched and weeded cotton. the low yields of cotton when unweeded or intercropped with peanut was due to plant competition.