Impact of high temperature on growth and development of Silkworm(Bombyx mori L.)

In Sericulture several factors contribute in the growth and development of silkworm for the production of good quality cocoons in farmer field, such as biotic and abiotic factors is of vital importance. Among the abiotic factors, temperature play a major role on growth and productivity in silkworm, as the poikilothermic insect.  To rear silkworms late age silkworm prefers relatively lower temperature than young age (Krishnaswami, 1994). Good quality cocoons are produced within a temperature. Increased temperature during silkworm rearing particularly in late instars accelerates larval growth and shortens the larval period. On the other hand, at low temperature, the growth is slow and larval period is prolonged (N. Suresh Kumar et al. 2003). The optimum temperature for normal growth of silkworms is between 20°C and 28°C and the desirable temperature for maximum productivity ranges from 23°C to 28°C. Temperature above 30°C directly affects the health of the worm. If the temperature is below 20°C all the physiological activities are retarded, especially in early instars worms become too weak and susceptible to various diseases (V. K. Rahmathulla, 2012).