Effect of Feeding Diafenthiuron 50 % WP Sprayed Mulberry Leaves on Growth and Development of Silkworm (Bombyx mori L.)

Abstract

Mulberry is the sole food for silkworm, due to evergreen lush foliage which attracts several pests majorly thrips and mites. Management of these pests demands usage of chemicals. Exposure to the residue of pesticides in the mulberry could affect the growth of silkworm and quality of economic traits, therefore it is important to observe the suitability of the chemicals used for managing these pests. An experiment was conducted to evaluate the effect of diafenthiuron, a novel pesticide having both insecticide and acaricidal property was sprayed on mulberry at 25 and 30th day after pruning and fed to the silkworms at 15 and 20 days after spray from 3rd instar onwards. There was no mortality observed in the treatment during two different rearing seasons. The larval duration was found to be shortest (24.15 days) after 20 days of spray, the larval weight (31.10 g/10 larvae), effective rate of rearing (97.66 %) was significantly maximum when silkworms were fed with diafenthiuron 50 % WP @ 1g/l sprayed mulberry leaves at 20 days of post spray. Thus, diafenthiuron 50% WP was found to be safe and suitable for use in mulberry without adverse effects on silkworm growth and productivity, with 20 days after spray being the most suitable feeding interval.