Infestation potential of Xanthopimpla konowi Krieger on tropical tasar silkworm cocoons and its mechanical management using nylon net.

Tropical tasar silkworm, Antheraea mylitta is an endemic wild silk fauna distributed in the tropical forests of India. Given the commercial value of tasar-silk, tribals and forest dwellers practice tasar-culture for their livelihood. Pre-designed rearing systems and tritrophic interaction have posed greater threats on silkworm by escalating natural enemies during outdoor rearing process decreasing the cocoon yield. Among the various natural enemies, the Xanthopimpla konowi is a noted parasitoid on A. mylitta affecting the production of both eggs and raw silk. Hence, this study was intended to reveal the infestation dynamics of X. konowi on tasar silkworms of Chhattisgarh in the past decade (2010–2021). X. konowi infested 1.87% to 6.13% of diapause seed cocoons of A. mylitta during 2010–20 and abruptly increased parasitisation of 12.08% in 2020–21. Heavy infestation in 2020–21 was recorded to be high in intensive rearing areas (20.87%) than extensive (4.93%) and exclusive bivoltine zones (4.34%). Further, the parasitization increased positively with the advancement of cropping season within the year in 2020–21. Moreover, the parasitization of X. konowi was significantly less (< 3%) on the cocoons harvested early and preserved inside the nylon net compared to delayed harvested and open field preservation (24%). Low paratisation was also observed in isolated rearing fields. Emergence pattern of X. konowi from diapause cocoons of heavy infested areas (24.74%, 8.10%, and 2.17% infested lots) obtained a normal curve compared to bimodal curve in low infested area lots (2.85%). [ABSTRACT FROM AUTHOR]