SWATHING WHEAT AND SURVIVAL OF WHEAT STEM SAWFLY

Abstract

Swathing wheat at the stage currently recommended does not reduce numbers of the wheat stem sawfly, Cephus cinctus Nort. (Hymenoptera:Cephidae), because most of the larvae are then well below the level at which the stems are swathed. Swathing early enough to cause larval mortality is impractical because the loss in yield would probably exceed the benefit gained by partial control of the sawflies.To prevent losses from sawfly cutting without reducing yield by swathing too early, swathing should not be started before the sawflies begin cutting. Because the sawflies begin cutting stems whose kernels contain more than 40% moisture, early swathing should be limited to fields that are heavily infested or to the margins of moderately infested fields.