Meysareh Shabarari - Department of Plant Protection, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili, ۵۶۱۹۹-۱۱۳۶۷, Ardabil, Iran.
Bahram Naseri - Department of Plant Protection, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili, ۵۶۱۹۹-۱۱۳۶۷, Ardabil, Iran.
Arash Zibaee - Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, ۴۱۶۳۵-۱۳۱۴, Rasht, Iran.
Jalil Hajizadeh - Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, ۴۱۶۳۵-۱۳۱۴, Rasht, Iran.

Willow leaf beetle, Plagiodera versicolora is an important pest of willow trees that feeds on the leaves both as larvae and as adults. -Amylases (EC ۳.۲.۱.۱) are the major insect digestive enzymes that catalyze the endohydrolysis of long -۱,۴-glucan chains such as starch and glycogen. In the current study, -amylase activity was studied in the midgut of larvae and adults of P. versicolora. Amylase activity in the midgut of larvae and adults was ۰.۶۸۰۷ and ۰.۱۱۶۲ µmol/min/mg protein, respectively. The optimal pH for -amylase activity of larvae and adults was ۴ and ۸, respectively and the optimal temperature for both was ۳۵ °C. The enzyme activity of larvae was inhibited by the addition of Na۲+, K+ and Zn۲+. K+ (at ۵ mmol) had the most positive effect on α-amylase activity in adults. EGTA had significant influence on decreasing the enzyme activity in larvae. EDTA had the most effect on increasing the activity of the enzyme in adults. Plant amylase inhibitors play important role against insect pests. Therefore, the characterization of digestive enzymes and the examination of inhibitors on the enzyme activity could be useful in tackling insect pests.

Plagiodera versicolora, midgut, α- amylase