Residual Effect of Chemical Insecticides used Against Thrips on Cocoon and Reeling Parameters of Silkworm Bombyx mori L

Author: Sithara H., Sandhya N., Ranjitha Bai H. and P. Harshita Mala

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Abstract

A study was conducted to evaluate the safety period and residual effect of chemical insecticides used against thrips through cocooning performance of silkworm Bombyx mori L. Insecticides were sprayed on mulberry at an interval of 25 (20 DAS), 30 (15 DAS) and 35(10 DAS) days after pruning. Among the treatments T2 (acetamiprid 20 SP @ 0.2 g / l) (82.78 %) recorded least cocooning per cent which was on par with T4 (acephate 75 SP @ 1 g/l) (88.04 %) most of the malformed cocoons and defective cocoons like flossy cocoon, double cocoon are obtained in T2 treated batch of silkworm. Acetamiprid recorded lowest cocoon weight (14.78 g/10 cocoons), shell weight (2.04 g/10 shells), pupal weight (12.74 g/10 pupae), cocoon shell ratio (13.84 %). Further Acetamiprid also recorded lowest reeling parameters like filament length (573 m), Non-breakable filament length (503.11 m), Filament weight (0.15 g), Denier (2.31)

Keywords

Silkworm, Cocoon, DAS, insecticides, acetamiprid

Conclusion

Acetamiprid belongs to neonicotinoid group of chemicals which shows systemic and translaminar action and it is also belongs to broad-spectrum insecticide, which is mainly used to control sucking pests but it also shows its effect on biting and chewing type of insects hence its residue on mulberry leaves showed adverse effect on silkworm performance with toxicity symptoms some ones grow almost normally during the larval period but die in cocooning frames due to lack of cocooning ability or some ones carry out cocooning but die inside the cocoons. Furthermore, abnormal cocoons with abnormal cocoon shells, normal cocooning but giving poor silk reeling etc. From this study it is suggested that fipronil and dimethoate had a reasonably good safety period of 15 days and resulted in better cocoon parameters

References

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How to cite this article

Sithara H., Sandhya N., Ranjitha Bai H. and P. Harshita Mala (2024). Residual Effect of Chemical Insecticides used Against Thrips on Cocoon and Reeling Parameters of Silkworm Bombyx mori L. Biological Forum – An International Journal, 16(8): 236-242