Overwintering, Oviposition, and Larval Survival of Hunting Billbugs (Coleoptera: Curculionidae) and Implications for Adult Damage in North Carolina Turfgrass

The hunting billbug, Sphenophorus venatus vestitus Chittenden, is one of the most widely recognized billbug turfgrass pests. Since 2000, damage to warm-season turfgrass caused by hunting billbugs has increased and a need for information on hunting billbug biology is necessary for the development of management plans. Field and laboratory studies were conducted to collect data on overwintering, oviposition behavior, larval survival at various levels of soil moisture, and adult damage. Turfgrass samples from ‘Tifway 419’ bermudagrass (Cynodon dactylon (L.) Pers × Cynodon transvaalensis Burtt Davy) on golf courses were collected to determine overwintering behavior, and 10 female adult billbugs were collected weekly to determine oviposition behavior. Survival of medium-sized larvae (head capsule width: 1.0 and 1.7 mm) was evaluated in containers with 20, 40, 60, or 80% of the total pore space occupied by water. Zero, two, four, or six adult billbugs were placed in bermudagrass, zoysiagrass, or tall fescue containers and images were collected for 4 weeks to determine adult damage. We observed that hunting billbugs overwinter as adults and all larval sizes. Adults became active in March and began to oviposit, which continued through October. Larval mortality was lowest with 20% of the total pore space occupied by water, while increases in moisture caused significant mortality. Adults caused a greater reduction in warm-season turfgrass cover than cool-season turfgrass cover. This research builds on the existing biological information for the hunting billbug biology in transition zones and will be pivotal in developing practical and sustainable management plans.