Field-Testing Pheromone Traps for Predicting Masked Chafer (Coleoptera: Scarabaeidae) Grub Density in Golf Course Turf and Home Lawns

Abstract

Sticky traps baited with crude female extract of the southern masked chafer, Cyclocephala lurida Bland, were tested at 28 sites on a golf course and on 27 individual home lawns to determine if the numbers of males captured in short-term trapping could be used to predict subsequent grub densities. Hexane rinses of female beetles were effective in luring males to traps. There was no correlation between male captures and local densities of grubs on the golf course, where movement of beetles between adjacent areas may have confounded our ability to discriminate among high- and low-density sites. In contrast, there was significant, albeit weak correlation (r2 = 0.25) between male captures and subsequent larval populations in home lawns, even though trapping was restricted to only two nights due to limited availability of crude female extract. Identification and synthesis of the C. lurida sex attractant would allow season-long trapping, which could provide a more accurate assessment of beetle populations and prediction of grub densities at particular turfgrass sites. The fact that most home lawns sampled did not develop damaging infestations underscores the need for improved methods of sampling and risk assessment to avoid unnecessary preventative treatments.