Surface Movement of Billbugs (Coleoptera: Curculionidae) in Harvested and Nonharvested Sod

Abstract

The billbug complex, Sphenophorus spp. (Coleoptera: Curculionidae), is an important pest on the sod farms of Georgia. The feeding damage of larvae within stolons and on roots delays the sod harvest and makes it difficult to conduct machine harvests. To develop an effective management strategy, the timing of insecticide applications is critical. The activity of billbugs, especially soon after sod harvest, has not been documented, as newly emerging adults could reinfest the harvested area or adjacent nonharvested sod fields. In 2019 and 2020, adult billbugs were sampled from harvested and nonharvested areas of sod farms by using linear pitfall traps. Although a significantly greater number of billbug adults were captured from the nonharvested sod, the data showed that adults were present in the harvested sod area. To understand the direction of billbug movement in harvested and nonharvested sod, a square area was selected, and the sod inside the square was removed. Linear pitfall traps were deployed along the perimeter of square areas to collect adults from outside and inside the square. In 2020, a significantly greater number of billbug adults were collected in the traps from the nonharvested areas outside the square than from harvested area inside the square, whereas in 2019, adult captures were similar from both areas. The data documented the activity of billbugs in the areas where sod was harvested, posing a risk of infestation for both strips of nonharvested grass in the harvested area and the adjacent, nonharvested sod fields that were near harvest.

Keywords: Sphenophorus spp; growth stages; turfgrass; zoysiagrass.