Impact Of Harvest Operations On Parasitism Of The Wheat Stem Sawfly Cephus Cinctus Norton Hymenoptera Cephidae

This is what should be left standing because it protects critical overwintering habitat. Removing only the wheat heads at harvest resulted in maximum parasitoid conservation. Special efforts to conserve parasitoids in solid stem wheat should be concentrated in areas of each field supporting above average crop growth because these high biomass areas harbor more overwintering cocoons. In hollow stem wheat the area 7.5 to 30 meters from the field margin is the most critical to conserve. If the hollow stem wheat has lower levels of infestation (less than 60% infested) the area to be conserved should extend to the field margin. These recommendations should be incorporated with other management practices that encourage sawfly parasitoids such as: solid stem wheat varieties, avoiding the use of insecticide during parasitoid flight, larger block fields, minimum tillage and chemical fallow. The improvement of parasitoid activity should further be incorporated into a complete integrated pest management approach including solid stem wheat, crop rotation, larger block fields and trap strips.