Predicted problems with black cutworm were minor with economic infestations found in a few scattered fields across the state. The black cutworm predictive model suggested heavy cutting by black cutworm to begin on May 9 in central Missouri. Good news concerning the model is that the May 9 prediction was accurate for those few fields that had economic infestations of black cutworm. The good news for producers is that numbers of economic infestations were limited and found mostly from Columbia to the east and north. This prediction was based on the high numbers of moths captured in central Missouri pheromone traps. However, this did not occur suggesting that data from an increased number of traps are needed to better reflect actual moth activity in an area. Damage from this pest was heavy in some fields where the 2-4 percent underground cutting threshold was greatly exceeded. Knowing why black cutworm moths select one field over another as a preferred egg laying site would be valuable information, but at this time no pattern is apparent for those fields supporting heavy larval infestations. It is possible that eggs were laid in many fields, but larvae were successful in only a few due to tillage, insect pathogens, environmental factors, or some unknown factor.

Similarly, high numbers of true armyworm moths reported from Missouri and neighboring states during early spring did not result in high numbers of first generation larvae. In most years 3 to 4 generations of true armyworm are produced in Missouri. Migrating moths often select grass pastures, wheat, fescue seed fields or occasionally field corn as their preferred egg laying sites during early spring. First generation larvae typically damage field crops with later generations attacking grass lawns. At present, low numbers of true armyworm larvae still can be found in grass pastures throughout the state, although damage is non-economic in most fields.

Some feeding on seedling corn by southern corn rootworm beetles (also call the spotted cucumber beetle) has occurred during the past two weeks. Infestations have been reported from most regions of Missouri with a few fields requiring insecticide applications to prevent further loss of seedling foliage. Although foliage feeding by Southern corn rootworm beetles occasionally occurs, reports this year are more numerous than in most years.

Wayne Bailey
573 864-9905 (cell)