SOME BIOCHEMICAL EFFECTS OF PLANT-EXTRACTS IN THE BLACK CUTWORM, AGROTIS-IPSILON (HUFNAGEL) (LEP, NOCTUIDAE)

Changes in the nutrient content and in the activities of carbohydrate digestive enzymes in the haemolymph of 6th-instar Agrotis ipsilon (Huf nagel) larvae were determined after feeding of larvae for 96 h on cast or bean leaves treated with selected plant extracts, at a concentratio n of 5%. Feeding of larvae on the petroleum ether extracts from Ammi m ajus and Apium graveolens, and acetone or/and ethanol extracts from Me lia azedarach and Vinca rosea [Cartharanthus roseus] resulted in a con siderable reduction in the total nutrient content, i.e. proteins, lipi ds and carbohydrates, of larval haemolymph as compared to that found i n the controls. However, slight changes in the nutrient content were f ound in case of larval feeding on leaves treated with water extracts f rom the selected plants. Moreover, the activities of haemolymph carboh ydrate digestive enzymes, especially amylase and invertase, were signi ficantly decreased as a result of larval feeding on the selected ethan ol extracts from M. azedarach and V. rosea. On the other hand, a consi derable increase in the activity of trehalase was found after larval f eeding on most selected plant extracts. It seems that the obserserved disturbances of nutrient content and carbohydrate digestive enzyme act ivities might affect larval growth.