Billbug (Coleoptera: Curculionidae) species composition, abundance, seasonal activity, and developmental time in...

Billbugs (Coleoptera: Curculionidae: Sphenophorus spp.) are common pests whose damage is often misdiagnosed on turfgrass in the United States. Consequently, Florida turfgrass managers have been struggling to satisfactorily control billbug outbreaks. Thus, we sought to determine the species complex, abundance, seasonality, and fecundity of key Sphenophorus spp. from field collections, and quantify duration of developmental and daily activity periods through greenhouse rearing tests. From January 2006 to December 2007, > 18,000 adults of 10 different Sphenophorus spp. were collected from four linear pitfall traps on each of two golf courses in north central and two courses in southern Florida. Sphenophorus venatus vestitus Chittenden was the most abundant species, making up > 94% of all specimens collected from three of the four golf courses (80.9% of all specimens collected). Adults were active and mature eggs were present in female ovaries nearly every week of the year. Adults were nocturnal. S. v. vestitus development from egg to adult can occur in 8-9 wk on 'Tifway' bermudagrass [Cynodon dactylon (L.) Pers.] or 'Empire' zoysiagrass (Zoysia japonica Steud.), with up to six overlapping generations per year, depending on environmental conditions. Thus, any time of year could be suitable to target either adults or larvae, and a repeated application may be needed to manage subsequently emerged larvae or eclosed adults.