Monitoring of the European corn borer (Lepidoptera: Crambidae) in central Maine

Pheromone trap types and within-field trap locations were compared for their effectiveness in monitoring the Eight activity of European corn borer, Ostrinia nubilalis (Hubner), and its relationship to egg mass density and crop damage in sweet corn in central Maine from 1995 to 1996. The use of both 3:97 Z:E-11-tetradecenyl acetate and 97:3 Z:E 11tetradecenyl acetate pheromone blends confirmed that European corn borer in central Maine is attracted to both pheromone lure types. European corn borer moths were captured predominantly with the E-lure type than with the Z-lure type in both years. The Scentry Heliothis trap was more effective than the Multi-Pher trap: but similar to the pheromone-baited water pan trap for monitoring European corn borer flights. With the Scentry Heliothis trap, the grassy border and Ist corn rows were the best locations for moth capture during the early flight period, but during the peak night period, traps located in the middle of the field caught tl-le most moths. Corn damage was recorded before moth captures in some sites and before egg mass counts in others, indicating poor efficacy of traps for early nights. Significant and positive correlations were found between moth captures in the midfield location and egg mass counts, and corn leaf damage, and between egg mass counts and corn leaf damage. However, low coefficients of variation suggest that pheromone trap captures were not good predictors of European corn barer leaf damage in sweet corn.