Although high numbers of black cutworm moths were captured in central Missouri, larval infestations and damage reports have been light statewide. Although few reports of damage are good for producers, it does question the precision or accuracy of the predictive model which uses intensive moth capture numbers and degree day calculations to predict first cutting by 4th instar BCW. Many factors can affect the growth or decline of a particular insect population. Traditionally, we know that BCW larvae have the potential to damage corn for about two weeks following seedling emergence. Late planted corn is at greater risk from this pest due to a better “fit” of larval development with the presence of seedling corn plants. Additionally, the presence of winter annual weeds and the timing of their control in the spring season also may influence numbers of this pest. In contrast, some factors which may hinder BCW populations may include:

• Low BCW moth numbers migrating into the state
• Trap captures not reflective of actual BCW moth population present in trap area
• Windy conditions during the egg laying period
• Spring tillage
• Insecticide seed treatments or planting time applications of insecticides
• Early planted corn that is too large to sustain larval damage
• Heavy rains occurring during larval emergence from eggs or when larvae are in the 1st instar stage of development
• High numbers of beneficial agents present in fields (corn field ants, insect predators, parasites, fungal and bacterial pathogens)

Wayne Bailey
573-864-9905