Effect of fraxinellone on growth and digestive physiology of Asian corn borer, Ostrinia furnacalis Guenee

A limonoid, fraxinellone significantly reduced the relative growth rate, food consumption rate as well as the efficiency of conversion of ingested food of the Asian corn borer, Ostrinia furnacalis when incorporated into artificial diets at concentration of 10 ppm and above. After being fed with diets that contained fraxinellone for 24 h, the larval midguts of O. furnacalis possess significantly lower activities of α-amylase and non-specific proteases and higher activities of cytochrome P450s. In vitro, the compound did not inhibit the activities of α-amylase and non-specific proteases extracted from the larval midguts. The modes of action of fraxinellone against the insect were discussed.