Impact of the automobile exhaust polluted mulberry (Morrus alba L.) leaves on the physiology and economical performance of the silkworm (Bombyx mori L.) in the Kashmir, India

Sericulture is the rearing of the silkworm to produce a fiber that has fascinated the man over millennia. Sericulture is an art as well as a science of rearing silkworms. The growth and development of the silkworm larva is affected by a number of biotic and abiotic factors including quality and quantity of the leaf, silkworm race and environmental conditions. Environmental pollution is one such factor which is turning to be a constraint affecting the quality and quantity of the mulberry leaves. Feeding these polluted mulberry (Morrus alba L.) leaves affects the silkworm growth as well as cocoon and silk production. Sericulture in Kashmir valley is being nurtured by mulberry trees mainly located on the road sides, river bunds, canals, farm/garden boundaries/fences, etc in an erratic manner. The release of various pollutants in the form of gaseous pollutants and particulate matter by the vehicular movement on these roads affects the nearby mulberry plantations and make the leaves unfit for silkworm rearing. The effect of the automobile exhaust polluted mulberry leaves was assessed by a bioassay involving the rearing the four different silkworm races , SH6 × NB4D2, CSR2 × CSR4, DUN22 × DUN6 and CSR double hybrid on the polluted mulberry leaves following the standard rearing procedures. The results enumerated that when these polluted mulberry leaves were fed to the Bombyx mori L., it caused stressful conditions for its growth and development, making it susceptible to various pathogens and affected its performance measured in terms of cocoon weight, shell weight and shell ratio. Providing the silkworm larvae with polluted mulberry leaves affected the nutritional indices of the silkworm including food ingestion, digestion, assimilation and conversion efficiency. Feeding the larvae with polluted mulberry leaves also resulted in the reduced growth and increase in the chawki mortality of the silkworm larvae. The rearing of the silkworm larvae with polluted mulberry leaves also caused the physiological disorder of the silk gland as revealed when the larvae were subjected to dissection. All the silkworm races, showed a marked effect when they were fed with polluted mulberry leaves, but CSR2 × CSR4 hybrid was most affected with the CSR double hybrid least affected.