Impact of spinosad and buprofezin alone and in combination against the cotton leafworm, Spodoptera littoralis under laboratory conditions

Abstract

Toxicity of the two biorational insecticides, spinosad and buprofezin and a mixture of the two was tested against the fourth instar larvae of the cotton leafworm, Spodoptera littoralis (Boisduval). The results showed that spinosad was more effective on the fourth instar larvae than buprofezin. The LC50 values for spinosad and buprofezin were 70.7 and 278.2 ppm, respectively. When spinosad was mixed with buprofezin, the percent of mortality increased; it was 85 %, compared with 63.3% in spinosad and 43.3% in buprofezin treatment. This means that the biorational insecticides spinosad and buprofezin can be used in a combination and cause good results with the cotton leafworm. This result suggested that the mixture of spinosad and buprofezin was more active than spinosad or buprofezin alone in all concentrations used. The larval duration, pupal period and adult longevity were not affected by all tested treatments. The number of eggs laid per female and percent of hatchability were affected in buprofezin and spinosad buprofezin in combination treatments compared with that in control. These results suggest that the combination of lethal effects of spinosad and buprofezin might affect pest population dynamics significantly by decreasing its survival and reproduction and by delaying its development. © JBiopest. 256.