EFFECTS OF FIVE NEW COMPOUNDS ON THE LARVAL GROWTH AND DIGESTIVE PHYSIOLOGY OF THE ASIATIC CORN BORER, OSTRINIA FURNACALIS LARVAE

Five new compounds were tested on the growth and antifeeding activity compared with toosendanin against fifth instar larvae Ostrinia furnacalis. The activities of two proteases, a weak alkaline trypsine‐like enzyme and a chymotrypsin‐like enzyme, in the midgut of Ostrinia furnacalis larvae were also measured. Experimental results suggest that when incorporated into an artificial diet at the concentration of 500mg/kg, the antifeeding activities of toosendanin, C₁₉, C₂₃, C₂₄, C₂₆, C₂₈ were 51.16%, 57.61%, 4.28%, 51.08%, 36.73% and 51.67%, respectively, C₁₉, C₂₄, C₂₈ had no significant difference with toosendanin. At 20mg/kg, the larval growth were remarkably suppressed by C₁₉, C₂₆, C₂₈, the inhibition of C₂₈ was close to toosendanin in 48 h. The two proteases were activated by toosendanin and C₂₈ while they were inhibited in 48 h but activated in 24 h by C₁₉, C₂₄ and C₂₆. In this paper, the related functions and mechanisms were discussed.