DAMAGE BY THE EUROPEAN CORN-BORER (LEPIDOPTERA, PYRALIDAE) TO WINTER-WHEAT

The effect of European corn borer, Ostrinia nubilalis (Hubner), injury during the spring on yield and yield components of winter wheat, Triticum aestivum L. em Thell, was studied. Spike and grain characteristics of infested and uninfested culms were compared in three fields of 'Florida 302' winter wheat in eastern Georgia. Feeding on inner stem tissue by larvae killed the grain spike producing a "white head" symptom in wheat. Most larvae (95.2%) tunnelled in the peduncle which caused an average of 3.4% of spikes to be barren. Larval injury did not reduce spike length but did reduce grain weight per spike by 44.6% and grain weight per kernel by 41.9%. Kernel number per spike was reduced by 11.7% mostly because of a 9.9% reduction in kernel number per spikelet. Spikelet number per spike was reduced by 1.8%. Tunnelling by O. nubilalis larvae also reduced grain test weight and quality. These results indicated that a culm infestation of 10% or more would be necessary before control measures would be justified in winter wheat.