Further evaluation of the efficacy of neem oil against Aphids (Aphis gossypii Clover) on sweet pepper (Capsicum frutescens L.)

Abstract

The study was conducted from December 1998 to May 1999 at the experimental field of the CPU College of Agriculture, Iloilo City. The objectives of the study were to evaluate the effect of the different concentrations of neem oil on the control of aphids and other pests, and to monitor the abundance of the natural enemies.

The six experimental treatments consisted of neem oil at 1500, 3000 and 4500 in parts per million, 40% neem leaf aqueous extract, Perla soap solution and the control (untreated). The treatments were arranged in a randomized complete block design with four replications.

Results of the study revealed that the use of neem oil at different concentrations had a better reducing effect than the other treatments on aphid population. The higher aphid density had favorably increased the number and kind of the natural enemies (Class Insecta and Arachnida) which in turn had augmented the control action of the spray solutions. White flies and grasshopper nymphs were controlled and repelled, respectively, by the neem preparations.

For economic reasons, the use of neem oil at 1500 ppm is recommended as weekly spray to control aphids, white flies and grasshoppers during the vegetative stage of pepper. Since the use of neem oil had shown a sign of favorable control against fruit flies, the concentration should be doubled from flowering to fruiting stage of the plant. When thrips is a problem, it is recommended that Perla soap solution be sprayed at four-day interval for total protection of the plants.