ALTERNATIVE USE OF LUFENURON AND CHLORPYRIPHOS IN THE MANAGEMENT OF HELICOVERPA ARMIGERA (HUBNER; AND PREVENTION OF RESURGENCE OF KEY SUCKING PESTS OF COTTON

摘要

The strategy involving the alternative use of lufenuron and chlorpyriphos was evaluated under field conditions against Helicoverpa armigera in cotton during 2004 and 2005. After 24 and 96 h of spray, no larval population was observed in case of chlorpyriphos (4 g a.i./l) alone and its larval population got reduced in all the treatments where pre-dosing with lufenuron (255 and 290 ppm) was done. Lufenuron @ 24 and 50 ppm alone did not control H. armigera. Chlorpyriphos at reduced dose / number of sprays with pre-dosing of lufenuron (24 and 50 ppm), however, significantly reduced the population of key pests of cotton. The repeated use of chlorpyriphos (4 g a.i./l) resulted in significantly higher jassid (3.68 to 4.04 nymphs/3 leaves) and whitefly (3.35 to 3.42 adults/3 leaves) population. The reduced dose of chlorpyriphos used in alternation with lufenuron prevented the resurgence of jassid and whitefly populations.