Effect of fenvalerate-20EC on sericigenous insects. II. Digestive enzymes in the nutritive physiology of silkworm, Bombyx mori L.

Changes in the activities of a few digestive enzymes after fenvalerate-20EC treatment were studied during the late stages of multivoltine and bivoltine silkworms, Bombyx mori. Insecticide treatment induced a reduction in the activity of such enzymes as amylase, sucrase, and protease, whereas the trehalase activity was enhanced when the midgut was used as the source of enzyme. The changes recorded in the activity of these enzymes indicated probable adverse effects of fenvalerate on silkworm metabolism through interference with the functional abilities of digestive enzymes.

Effect of fenvalerate-20EC on sericigenous insects. I. Food utilization in the late-age larva of the silkworm, Bombyx mori L.

The effect of the common pyrethroid insecticide fenvalerate-20EC (Sumicidine-20EC) on food utilization parameters in the pure multivoltine (Pure Mysore) and pure bivoltine (NB4D2) races of silkworm, Bombyx mori, fed ad libitum with Morus alba, was studied in the final two instars. Insecticide treatment was found to reduce the rates of feeding, assimilation, and conversion along with the efficiencies of conversion of ingested and digested food into body substance. This was due to the toxic effects, which interfered with the silkworms' feeding behavior, and physiology of digestion, and the magnitude of changes increased with the increase in the concentration of fenvalerate used.