Effect of some medicinal plants on developmental and economic parameters of mulberry silkworm

A detailed investigation was undertaken to evaluate the medicinal plant extracts against Bombyx mori L. Amongst Vitex negundo, Centella asiatica, Murraya koenigii, Colius aromaticus, Mentha arvensis, Pelargonium graveolens and Majorana hortensis at 1, 2,5 and 10% aq. conc. against 21 d old larvae of B.mori, only four had preference index of more than one and acted as strong feeding stimulant, viz. V. negundo and C. asiatica (at 1, 2, and 5% conc., each), P. graveolens and M. koenigii (at 2%, each). High feeding deterrent property was exhibited by C. aromaticus (5.28 cm²) and M. arvensis (5.35 cm²) over control (13.37 cm²) at 1%. In a growth and development study against 20d old larvae of B. mori, none of these could cause any significant effect on larval period, pupal weight and survival of B.mori.