We compared the susceptibility of the introduced Popillia japonica and the native Cyclocephala borealis to 16 species and strains of entomopathogenic nematodes isolated from within or outside the geographic ranges of the two scarabs. We found large variation in the virulence of the species/strains of nematodes with over 50% mortality of P. japonica produced by Heterorhabditis zealandica strain X1 and H. bacteriophora strain GPS11 and of C. borealis by H. zealandica and H. bacteriophora strains KMD10 and NC1. Heterorhabditis indica and H. marelatus caused <20% mortality of both scarab species. Dose response studies with selected nematode species and strains against P. japonica and two additional non-native species Anomala (Exomala) orientalis and Rhizotrogus majalis and the native C. borealis indicated that R. majalis was the least susceptible and P. japonica and A. orientalis were as susceptible as the native C. borealis. Heterorhabditis zealandica was significantly more virulent than any other species or strain against P. japonica with a LC50 of 272 infective juveniles/grub. The LC30 and LC50 values for H. zealandica were also the lowest among the four nematode species/strains tested against A. orientalis and C. borealis. The LC50 values for H. zealandica and H. megidis (UK strain) were significantly lower for the native C. borealis than the introduced A. orientalis. Heterorhabditis zealandica also showed the highest penetration efficiency and the lowest encapsulation in P. japonica and C. borealis grubs. Field trials also revealed superiority of H. zealandica over all other nematodes species and strains tested in controlling both P. japonica and C. borealis.
Species 1: Coleoptera Scarabaeidae Popillia japonica (Japanese beetle)
Species 2: Coleoptera Scarabaeidae Cyclocephala borealis
Species 3: Coleoptera Scarabaeidae Anomala orientalis
Keywords: entomopathogenic nematodes, white grubs
Back to Arthropod Pests of Turfgrass
Back to Formal Conferences
Back to The 2002 ESA Annual Meeting and Exhibition