Impact of Pesticide Treated Mulberry Leaves on Cocoon Traits of Silkworm Hybrid FC2

Abstract

A bioassay was conducted to evaluate the effects of feeding pesticide-treated mulberry leaves on cocoon parameters of silkworm hybrid FC2 during the year 2022-23 at the College of Agriculture, Chamarajanagara. Five pesticides which are used for mulberry pest management were applied at recommended label doses and silkworms were fed with treated leaves at 5, 10, 15 and 20 days after spraying (DAS) to assess residual effect. Among the treatments, Azadirachtin 1% (2 mL/L) and Chlorfenapyr 10 SC (1.5 mL/L) significantly reduced cocoon yield, cocoon shell weight and shell ratio particularly at 5 and 10 DAS. In contrast, the botanical pesticide Orgomite (2.5 mL/L) consistently recorded the highest values for cocoon yield, shell weight and shell ratio indicating minimal adverse effects. Wettable Sulphur 80 WP (2 g/L) and Era Safeguard (2.5 mL/L) had moderate impacts with partial reductions in cocoon parameters. Differences among treatments diminished by 15 and 20 DAS suggesting reduced toxicity over time. Overall, Orgomite was identified as the safest treatment with favorable cocoon traits, while Chlorfenapyr 10 SC required a longer safety interval to minimize its negative effects. The study highlights the importance of considering pesticide residue effects and waiting periods in sericulture to ensure optimal cocoon quality.