Bionomics and Seasonal Abundance of the Banded Sunflower Moth (Lepidoptera: Cochylidae) on Cultivated Sunflower in the Northern Great Plains

Abstract

The banded sunflower moth, Cochylis hospes Walsingham, is a pest of cultivated sunflower, Helianthus annuus L., in the northern Great Plains. Adults were first detected between 7 and 11 July in each year between 1983 and 1986. Adult population peaks aldo showed little variation among years, appearing on 22-25 July each year. Oviposition on the heads (capitula) occurred when plants were in the early-bud stage through anthesis (R2-6). Sunflower plants were in the early bud stage (R2-3) when larvae were initially found between 14 and 23 July each year. Larvae were present in sunflower heads for 6-10 wk and reached peak abundance in early to mid-August. After eclosion, larvae fed on the inner surface of the head bracts or florets. The entire immature seed may be consumed by the developing larva. Older larvae (third to fifth instars) entered and fed on mature seeds after chewing a hole in the apical end of the hull (pericarp). After consuming the majority of the kernel, larvae moved to a new seed. Mature larvae dropped to the soil and constructed silken cocoons to overwinter. Linear regression analysis of measurements of head capsule width and body length substantiated that the larvae develop through five instars. Seasonal patterns of the life stages of banded sunflower moth were similar, but population densities varied among years. There was one generation per year. Each larva consumed more than six mature sunflower seeds.