D3042: Evaluating early season asiatic garden beetle, Maladera castanea, damage in field corn

The Asiatic garden beetle (Maladera castanea Arrow) is an invasive annual white grub species that has recently begun causing significant damage to field corn grown in sandy soils of northern Ohio, northern Indiana, and southern Michigan. Early season root feeding on seedling corn by successfully overwintered grubs can result in stand loss exceeding 40%. Currently there are no formal management recommendations for this species in field crops. An important aspect of an integrated pest management program is an economic threshold indicating when treatment action is recommended to prevent economic loss. The goal of this project is to develop an economic threshold for Asiatic garden beetle in corn based on the relationship between grub density, plant health, and economic factors. The objective of this experiment is to determine the correlation between grub density and reduced plant health in field corn. We grew corn plants in both the greenhouse and in field microplots with varying grub density. A subset of plants were destructively sampled to evaluate root feeding damage, and the remainder were monitored for symptoms of feeding, delays in development, and yield. These data allow us to determine the relationship between grub density and plant damage in controlled settings and will serve as the basis for future studies.