Abstract
A field experiment was conducted at Mersan, South Haiti during the period of November 2003 to April 2004 to evaluate the effect of wood shaving mulch and sequential applications of the insecticides azadirachtin, lambda-cyhalothrin and profenfos on onion thrips (Thrips tabaci Lindeman) infestation and the yield of onion (Allium cepa L.). A randomized complete block factorial design was utilized in four replications. The first factor consisted of unmulched and wood shavings mulched onion; while the second factor consisted of control (without insecticide), azadirachtin, profenfos, lambda-cyhalothrin, azadirachtin alternated with profenfos, azadirachtin alternated with lambda-cyhalothrin, profenfos alternated with lambda-cyhalothrin, azadirachtin alternated with profenfos and lambdacyhalothrin. The cultivar Yellow Granex was utilized. Thrips infestation was lowest when the onion crop received three consecutive applications of Lambda-Cyhalothrin. Onion yield was not significantly influenced by pesticide application sequences, but mulching increased both the total yield and the commercial yield of onion. The results of this experiment suggest that wood shaving mulch can improve onion yield under the agroecological settings of the area of Mersan. They also lead to the conclusion that Lambda-Cyhalothrin can be recommended for the control of onion thrips.
