Effects of flupyradifurone application timing and Re-application on the rhodesgrass mealybug (Hemiptera: Pseudococcidae) suppression and quality of golf course putting greens

Rhodesgrass mealybug, Antonina graminis Maskell (Hemiptera: Pseudococcidae) is an important pest on the putting greens of golf courses in the southern USA. Antonina graminis feeding damage on the putting greens appears as the yellowing of foliage, which gradually turns brown, affecting the aesthetics, playability of golf and turfgrass quality. Although systemic insecticides, such as flupyradifurone, have proven effective against A. graminis, the timings of their application and reapplication during the growing season have not been determined. Thus, this study aimed to determine the effects of single and repeated applications of flupyradifurone on the counts of A. graminis and turfgrass quality. The flupyradifurone treatments were applied at 1) June only, (2) July only, (3) August only, (4) June + July, (5) June + July + August, and (6) nontreated. In 2019 and 2021, the experiment was conducted on the putting greens in Columbus, Georgia, USA. A single application of flupyradifurone during the early summer (June or July only treatments) did not reduce the A. graminis counts or improve turfgrass quality, whereas a single application in late summer (August only treatment) reduced A. graminis counts and improved turfgrass quality for at least 30 d post-application. Repeated applications of flupyradifurone until August (June + July + August treatment) significantly reduced the numbers of A. graminis and improved turfgrass quality. There was no significant difference between August only and June + July + August treatments on the A. graminis counts and turfgrass quality. Thus, the late summer application of systemic insecticide is likely to provide adequate A. graminis control.