Influence of Trap Crop on Yield and Cotton Leafhopper Population and Its Oviposition Preference on Leaves of Different Cotton Varieties/Lines

Abstract

The experiment was set up as a split plot design, with four replications. White and naturally colored cotton of 4 varieties/lines, each was cultivated in monoculture, and with perimeter trap cropping and row intercropping with okra and castor bean at Thong Pha Phom, Kanchanaburi and with okra , and sunflower and castor bean at Nakhon Ratchasima Field Crop Research Center during the dry and late rainy seasons of the year 2008 respectively. The populations of leafhopper (Amrasca biguttula Ishida) were recorded from top and bottom leaves 30, 60 and 75 DAP (days after planting) and expressed as an average number / 2 leaves. The plots with trap crops were found to decrease in a number of leafhopper while yields increased comparing to the sole cotton in every variety/line. Choice test on oviposition preference was undertaken in the nylon cages holding 10 plants of each cotton variety/line exposed together to 20 leafhopper females for 2 weeks. The results from 20 leaves of each showed more egg numbers in the lateral vein than in the mid vein with no significant differences among test varieties/lines.