Impact of some medicinal plant extracts on cocoon production of eri silkworm, Philosamia ricini Huttchinson.

摘要

An investigation was carried out to study the effect of aqueous extracts (25 and 50% concentration fresh weight basis) of 12 medicinal plants on the feeding activity, biological and economic parameters of eri silkworm, Philosamia ricini Huttchinson. Among the 12 plants tested only four had preference index of more than one and acted as strong feeding stimulant, viz., Andrographis paniculata 25 per cent (1.18), Aloe barbadensis 50 per cent (1.16), Andrographis paniculata 50 per cent (1.13), Bacopa monnieri 25 per cent (1.12) and Withania somnifera 25 per cent (1.05). The larval weight gain was maximum in B. monnieri 50 per cent (1.40 g) followed by A. paniculata 50 per cent (1.37 g) over control (1.29 g). None of the plant extracts significantly reduced or increased the larval duration. The highest cocoon weight was observed in B. monnieri at 25 per cent (1.86 g) followed by W. somnifera and B. orellana at 25 per cent (1.84 g), A. paniculata at 50 per cent (1.82 g) over control (1.75 g). It is concluded that fortifying castor leaves with medicinal plant extracts enhances cocoon weight, shell weight and shell ratio.