FIELD-TESTING PHEROMONE TRAPS FOR PREDICTING MASKED CHAFER (COLEOPTERA, SCARABAEIDAE) GRUB DENSITY IN GOLF COURSE TURF AND HOME LAWNS

Sticky traps baited with crude female extract of the southern masked c hafer, Cyclocephala lurida Bland, were tested at 28 sites on a golf co urse and on 27 individual home lawns to deter-mine if the numbers of m ales captured in short-term trapping could be used to predict subseque nt grub densities. Hexane rinses of female beetles were effective in l uring males to traps. There was no correlation between male captures a nd local densities of grubs on the golf course, where movement of beet les between adjacent areas may have confounded our ability to discrimi nate among high- and low-density sites. In contrast, there was signifi cant, albeit weak correlation (r2 = 0.25) between male captures and su bsequent larval populations in home lawns, even though trapping was re stricted to only two nights due to limited availability of crude femal e extract. Identification and synthesis of the C. lurida sex attractan t would allow season-long trapping, which could provide a more accurat e 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 m ethods of sampling and risk assessment to avoid unnecessary preventati ve treatments.