Technical Abstract: The sunflower seed maggot, Neotephritis finalis, is an emerging pest of cultivated sunflower in the northern Great Plains sunflower production region. It is a seed-feeding pest and infests the sunflower plant from late bud stage through flowering. There are two generations in North Dakota. Adults of the first generation emerge in early July and the second generation at the end of August. Females lay eggs in the developing sunflower head. Crop injury is caused by feeding of the larval stages. After hatching, first instars feed on developing seeds. The magnitude of damage to sunflower seeds is dependent on the density of larvae and stage of crop development. One larva can cause seed sterility by feeding on 10 or 12 young florets. Mature larvae feeding on older sunflower heads can destroy one to three seeds. Injury to sunflower can result in a deformed head caused by a creasing and folding toward the center of the head. Effective pest management strategies are needed because of the increasing impact of the seed maggot in commercial sunflower fields. Field studies were carried out at Prosper, ND, in 2008. Planting date studies with other sunflower pests have demonstrated that delayed planting is effective in reducing damage. However, comparison of healthy seed weight from two planting dates did not show any significant difference. Results from the evaluation of insecticides and timing of spraying showed a significant impact on the yield among treatments. A foliar insecticide applied at the beginning of bloom resulted in a higher weight of healthy seeds than the untreated check, indicating that insecticide spraying can be targeted at the adult maggot to prevent egg laying and reduce larval damage. Research will continue in 2009 at additional locations in North Dakota.