Reduced Whitefly Infestations in Cotton Using a Melon Trap Crop

A second year of field experiments was completed in 1999 at MAC that explored the potential of using a melon trap crop to reduce whitefly infestations in cotton. The experimental design was altered from 1998 to gain isolation among treatment blocks by using 4 separate fields that helped to avoid the influence of one treatment upon the other. A consistent response of significantly fewer whiteflies in cotton planted within a surrounding melon trap crop, relative to the same area of cotton without the trap crop, was observed throughout the JulySeptember sampling period. Better chemical management of whiteflies in the melons during the second season helped to reduce the large differential in whitefly densities between melons and cotton observed the previous year, but preferentially contributed to a greater differential observed between melonprotected cotton and unprotected cotton. Although the infestation buildup was delayed and the season-long densities of whiteflies in the melon-protected cotton were reduced, the action thresholds for treatment with IGRs were ultimately attained and exceeded. In the present management environment of perhaps only 1 IGR treatment per season, it is unlikely that the melon trap crop approach would provide acceptable control unless a grower was willing to tolerate lateseason whitefly densities higher than the current IPM recommendations.