D3041: Effects of cover crops and entomopathogenic nematodes on corn rootworm survival and feeding injury to corn

Western corn rootworm Diabrotica virgifera virgifera LeConte and northern corn rootworm Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae) are serious pests for corn. These species overwinter in the soil as eggs, with larvae feeding on the roots of the corn plants upon eclosing. My research focuses on how cover crops and entomopathogenic nematodes (EPNs) affect survival of western corn rootworm larvae and feeding injury to corn. Past research suggests that these management practices may reduce corn rootworm survival and feeding injury. I will study a total of four fields, located in central and southern Iowa, with each field divided into four treatments: 1) experimental control: absence of EPNs and cover crop, 2) presence of the EPN Steinernema feltiae Filipjev, 3) winter cover crop, and 4) S. feltiae and winter cover crop. Each field will have two strips of corn lacking Bt traits targeting rootworm, and not treated with soil-applied insecticide, and these strips will intersect all treatments. In these strips, I will evaluate root injury caused by rootworm larvae and rootworm survival. Additionally, I will collect soil samples from treatments within each field and test for the presence of EPNs based on baiting of EPNs from soil with larvae of the greater wax moth Galleria mellonella (L.) (Lepidopteran: Pyralidae). Data from this research will enable me to test whether EPNs and cover crops may reduce rootworm feeding injury and rootworm abundance, and the extent to which these factors might aid in the management of rootworm.