Manganese from Soil to Silk in Tasar Silkworm, Antheraea mylitta Drury and Its Effect in Cocoon Yield Manganese from Soil to Silk in Tasar Silkworm, Antheraea mylitta Drury and Its Effect in Cocoon Yield

Abstract

An investigation on the status of available manganese in soil and its content in a leaf of the host plant, larva, pupa, excreta, and cocoon shell of Tasar silkworm, Antheraea mylitta Drury was undertaken to study the dynamics and impact of consumption of manganese in cocoon production. Availabilities of Mn, Fe, Cu, and Zn in the soil of Tasar rearing plot at Nagri, Ranchi was found as 82.79 ± 9.78 mg/kg, 23.32 ± 2.96 mg/kg, 0.83 ± 0.202 mg/kg, and 0.68 ± 0.097 mg/kg, respectively. Manganese is adequately available in the soil, but its contents in leaf, larva, litter, pupa, and cocoon shell vary remarkably. The content of manganese in the leaf of Terminalia tomentosa was found in the range of 50–100 ppm which was optimum for the success of the crop. Excess consumption of Mn by the larva of Tasar silkworm resulted in the failure of the crop yielding 2 cocoons/dfl when reared on Shorea robusta which has Mn content in the range of 353 ppm–2543 ppm. Daily requirement of manganese in optimum level for healthy development of Tasar silkworm larva of Daba bivoltine Eco Race was calculated to be in the range of 0.007–0.035, 0.018–0.36, 0.045–0.090, 0.099–0.198, and 0.354–0.708 mg for 1st, 2nd, 3rd, 4th, and 5th instars, respectively. Manganese content in a leaf of Shorea robusta (Sal) indicated that its translocation capacity compared to Terminalia arjuna (Arjun) and T. tomentosa (Asan) is very high which is detrimental for the health of Tasar silkworm of Daba bivoltine Eco Race.