Effects of physical barrier and insect growth regulator on whitefly control and yield of chili pepper (Capsicum annuum L.)

摘要

Whitefly is a serious pest of chili pepper that could cause direct damage on the plant or serve as carrier of viral diseases. A study was conducted at the experimental farm of the Crop and Ecosystem Management Unit of AVRDC-The World Vegetable Center in Tainan, Taiwan, to evaluate the effects of nylon net as physical barrier and pyriproxyfen, an insect growth regulator (IGR), alone or in combination on controlling whitefly and yield of chili pepper. The experiments were laid-out in a randomized complete block design with three replications. The treatments were employed over an open field crop with the crop row covered with nylon net mesh #32 or #50 with or without pyriproxyfen applied at recommended rate. Results revealed that nylon mesh #50 was effective in excluding whiteflies compared to nylon mesh #32. Pyriproxyfen also reduced the number of whitefly count. However, based on a total of five harvests, yield decreased by 27% and 42% under nylon net barrier #50 and #32, respectively, compared to open field cultivation. Plants grown under nylon net were significantly taller in length and had higher leaf area index, or leaf and stem dry matter content but lower the fruit dry matter content.