Impact of heavily polluted air and acid rain on mulberry silkworm and cocoon production of Bombyx mori Linn

Abstract

The silk is the protein polymer spun into fibers by the silkworms (Bombyx mori L). It is a textile fiber highly appreciated for its outstanding properties (handle, luster, dye ability, comfort). In addition, silk has been recently investigated as a starting material for nontextile applications. In order to assess the effect of air pollution on the yield and quality of silk fibers, two locations of Indian locality had been chosen on the basis of the ambient air quality for rearing of mulberry silkworm, Bombyx mori L. Air pollution may be indicated by the higher acid rain. Air pollution caused by the burning of fossil fuels increase emissions of SO2, NO2, and CO2 which can ultimately lead to acid rain. Exposure of acid rain may affect the cultivation of mulberry and the quality of silkworm cocoon. The aim of this research was to determine the effect of mulberry plants that have been exposed to acid rain to the percentage of cocoon defects and type of defects in multivoltine races for tropical climates like C-nichi and Hosa mysore races of Bombyx mori L. Acid rain that to applied on mulberry plant for 5 weeks was a modification of acid rain that occurred in tropical area. A total of 400 individuals of newly hatched silkworm were used in early research. Larvae fed by mulberry leaves that had been treated with artificial rain water in different levels of pH, i.e., pH’s of 7.0 (well water as control), 6.0 (normal rain), and 5.0 (acid rain). Cocoon defects and type of cocoon defect were observed. Data were analyzed using multivariate ANOVA test. The results showed that the treatments had significant effect on defective cocoon percentage. Treatment of pH 7.0, 6.0, 5.0 had defective cocoons of 20%, 13%, 10%, respectively in race C-nichi 18% and 15% respectively in race Hosa mysore. Meanwhile, cocoon defect types in race C-nichi and Hosa mysore were outer defects consisting of printed, outside stained, malformed, very small, double cocoons, and inner defect consist of thin end and inside stained and luster of cocoons. As a whole, acid rain treatments to defective cocoon of Bombyx mori L. in C-nichi and Hosa Mysore races showed significant effect to defective cocoons.