Pest Management of Wheat Stem Sawfly, Cephus Cinctus Norton (Hymenoptera: Cephidae), in Western North Dakota

Abstract

The wheat stem sawfly, Cephus cinctus Norton, is regarded as a major pest of dryland wheat in the Upper Great Plains. For peak emergence of wheat stem sawfly, the most accurate base was 0 C using air temperature, and then degree-day base of 0 C using soil temperatures. For Bracon cephi, the most accurate base temperature was the lower degree-day base using air (0 C) and soil (0 C) temperatures. The solid-stemmed varieties, Mott and Choteau, exhibited the highest stem solidity and also experienced the lowest percentage of wheat stem sawfly damaged stems. The hollow-stemmed varieties, Glenn, Reeder and Steele ND, had the lowest levels of solidity and usually the highest percentage of wheat stem sawfly damaged stems. When wheat stem sawfly populations were high, the solid-stemmed wheat varieties, Mott and Choteau, had yield, test weight, and protein that were comparable to the hollow-stemmed varieties, Glenn, Reeder and Steele ND.