Assessing the Impact of Abamectin and Diafenthiuron on Silkworm Larval Growth and Survival

Abstract

An experiment was conducted primarily to evaluate chemicals exhibiting dual insecticidal and acaricidal properties, with a specific focus on their compatibility with silkworms and indigenous natural predators within the mulberry ecosystem, to evaluate abamectin 1.9% EC and diafenthiuron 50% WP for safety period on mulberry silkworm, Bombyx mori L. (Jan-Feb and Mar-April 2023) where in the pesticides were sprayed on mulberry at different durations, after spray were fed to the silkworms from third instar onwards. There was no mortality (0.00%) of silkworm observed in the treatments during two seasons and the larval progression 100% during third, fourth and fifth instars. The total larval duration was found shortest when the silkworms were fed with mulberry leaves harvested from the plots sprayed with abamectin 1.9% EC at 0.75ml/lit (22.30 and 23.22 days) and diafenthiuron 50% WP at 1 g/lit (22.77 and 23.07 days) at 15 and 21 DAS, respectively. The larval weight was significantly maximum in the treatments with abamectin 1.9% EC at 0.75 ml/lit (4.29 and 4.08 g/larvae) and diafenthiuron 50% WP at 1 g/lit (4.17 and 4.06 g/ larvae), respectively at 15 and 21 DAS. The Effective Rate of Rearing (ERR %) was found highest with diafenthiuron 50% WP at 1 g/lit (97.78 and 96.67 % at 15 and 21 DAS) and abamectin 1.9% EC at 0.75 ml/lit (97.78 and 96.67 % at 15 and 21 DAS) that was comparable with control. The molecules, diafenthiuron 50% WP at 1 g/lit and abamectin 1.9% EC at 0.75 ml/lit were found safer to silkworms at 15 and 21 DAS in terms of survival and larval growth.