The Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a significant limiting factor in the production
ofwheat and barley inmany areas of the world. In the current study, the effect of semi-purified proteinaceous
extracts of seeds on digestive enzymes, and the growth and development of the Sunn pest were studied.
The results showed that the purified α-amylase inhibitor from Triticum aestivum (type ) and rice semi-purified
seed extract did not significantly affect the Sunn pest α-amylase activity. However, bean and cowpea seed
extracts significantly affected α-amylase activity in vitro. For example, the bean seed extract at concentrations
of 0.125 and 2.0 mg · mL−1 inhibitedα-amylase activity of the pest by 15% and 45%, respectively,while the cowpea
seed extract, at the same concentrations, inhibited α-amylase activity of the pest by 9% and 40%, respectively.
Further, incorporation of the seed extracts into the insect diet showed that the rice seed extract did not affect insect
development time, while bean and cowpea seed extracts at high concentrations (e.g., 3.0%) significantly affected
nymphal development time and survivability (P N 0.05). These results show that semi-purified seed extracts affect
α-amylase activity, developmental time, and survivability but not the adult weight of the Sunn pest.
© 2013 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection