ABSTRACT

The wheat stem sawfly is a native pest of major economic importance in the northern Great Plains of North America. The pest was first collected in wild grasses, and soon appeared in wheat after tillage began. The narrow window of susceptibility of wheat has resulted in early-season activity of sawfly wasps. Early-maturing winter wheat previously avoided attack, but now is heavily infested.

Sawflies in wild grasses are attacked by many species of parasitoids, but only two species of braconid parasitoids commonly attack sawflies in wheat. These two species are bivoltine, and are not well synchronized with sawfly hosts in wheat.