Efficacy of Some Pesticide Alternatives on the Desert Locust Schistocerca gregaria (Forskal) Under Laboratory and Field Conditions
The efficacy of chlorantraniliprole (Coragen®), spinosad (Tracer®) and fipronil (Coatch®) was tested under laboratory conditions against the 5th nymphal instars and adult stages of the Desert Locust Schistocerca gregaria (Forskal), using various concentrations of the mentioned compounds by feeding technique. Fipronil showed the highest efficacy on both stages, followed by spinosad while chlorantraniliprole caused lower mortality. The effect of sublethal concentrations (LC30) of the mentioned insecticides on the life span and fledging rate of 5th nymphal instar was investigated. 5th nymphal instar took 12.6, 15.6 and 11.6 days to fledge in the treatments of chlorantraniliprole, spinosad and fipronil respectively, which are significantly longer than the duration spent by the untreated 5th nymphal instar to fledge (8.8 days). Successful fledging rates of 5th nymphal instars were 42.6%, 75% and 25% for the treatments of chlorantraniliprole, spinosad and fipronil respectively, which are significantly lower than that of the untreated hoppers (100% fledged successfully). Deformation occurred in 30% of the 5th nymphal instars treated by LC30 of fipronil and spinosad. Field tests, executed in Abu_Ramad, southeast Egypt, showed that chlorantraniliprole at dose rate of 24 g. a. i. /ha, spinosad at dose rate of 15.12 g. a. i. /ha, and fipronil at dose rate of 0.4 g. a. i. /ha, resulted in 98, 99 and 100% mortality to mixed populations of hoppers and adults of S. gregaria within two days of field application.