Field Efficiency of Some Insecticide Treatments against Whitefly, Bemisia tabaci, Cotton Aphid, Aphis gossypii and Their Associated Predator, Chrysopa vulgaris, in Cotton Plants

摘要

The efficiency of two chitin synthesis inhibitors (pyriproxyfen and novaluron), compared with three neonicotinoid insecticides (thiamethoxam, imidacloprid and acetamiprid) and chlorantraniliprole against Bemisia (abaci, Aphis gossypii and their associated predators were determined in cotton fields. The experiments were carried out during 2012 and 2013 cotton seasons at Lakana village, Shobrakeate, El-Beheira Governorate. Results showed that, statistically, all tested insecticides were comparable against B. tabaci adults except chlorantraniliprole which recorded the least reduction percentages at 2012 and 2013 cotton seasons. The same results also were recorded with B. tabaci immature stages at 2012 and 2013 cotton seasons. Concerning A. gossypii, the neonicotinoid insecticides (thiamethoxam, imidacloprid and acetamiprid) recorded the highest mean reduction (89.99, 88.79 and 76.86%) at 2012 and (95.05, 94.61 and 94.90) at 2013. On the other hand, the chitin synthesis inhibitors (pyriproxyfen and novaluron) achieved the least reduction percentages against A. gossypii in both seasons. The neonicotinoids revealed a residual toxicity higher than, the chitin synthesis inhibitors on B. tabaci and A. gossypii, while chitin synthesis inhibitors revealed aresidual toxicity higher than chlorantraniliprole against B. tabaci. Under the same conditions, all treatments have moderate toxic effects on the natural enemy Chrysopa vulgaris except chlorantraniliprole which recorded low toxic effects in both seasons.