WHEAT-STEM SAWFLY (HYMENOPTERA, CEPHIDAE) DAMAGE, RATES OF PARASITISM, AND OVERWINTER SURVIVAL IN RESISTANT WHEAT LINES

Solid-stemmed spring wheat cultivars have been used since 1945 to reduce losses caused by the wheat stem sawfly, Cephus cinctus Norton. Solid-stemmed wheats currently are attacked, but infestation rates, plant damage, and yield loss are lower than in hollow-stemmed cultivars. Stem solidness had no effect on parasitism rates by two prevalent Bracon species. C. cinctus larvae usually were unable to tunnel downward through solid stems to reach preferred underground regions for overwintering. Larvae did not survive overwinter above ground.