Exploring sunflower resistance to sunflower moth

Sunflower moth, Homoeosoma electellum, is a serious pest of sunflower crops. In this study, we hypothesize that rate of pericarp hardness is a resistance trait against sunflower head moth. Objectives are to 1) evaluate pericarp hardness rate and 2) evaluate larval injury to pericarps. Bioassay feeding preference studies using fourth instar larvae will be used to access pericarp hardness effects on sunflower moth. Hardness measurements will be determined by means of physical compression tests, as performed in 2014 screening. Four varieties were selected from 2014 screening for hardness traits from thirty commercial hybrids, cultivars, and lines of sunflowers. Sunflower entries were planted in early-June and data collection began in August, when sunflowers reached R5 development stage. The outcomes of these results will help sunflower producers save cost on chemical control measures and may reduce pest risk for earlier planting dates.