Effects of Cysteine Proteinase Inhibitors scN and E-64 on Southern Corn Rootworm1 Larval Development

Abstract

Abstract. The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, can be a serious pest of peanut (Arachis hypogaea L.) pods. A laboratory bioassay was developed to test feeding cysteine proteinase inhibitors soyacystatin N (scN) and E-64 against southern corn rootworm reared on artificial diet to determine the effects on larval development and mortality. Soyacystatin N increased mortality of larvae and decreased larval development as measured by live weights at 4 and 7 d. Seven d weight gain for larvae in the control increased by 66%, while the 0.5, 1.0 and 2.0 mg/ml doses decreased by 50, 42, and 79%, respectively. The proteinase inhibitor proved to be a good candidate as a means of host-plant resistance for reducing larval development and increasing the chance to interrupt metabolism and increased mortality. E-64 also demonstrated significant larval mortality and decreased weight gain when fed through artificial diet. At 7 d, after feeding on the 0.50, 1.0, and 2.0 mg/ml doses, larval we...