Abstract

Preplant potting mix incorporation of Talstar 0.2G (bifenthrin) can prevent root weevil and white grub infestations in container-grown nursery crops. Analysis of bifenthrin residues from potting media aged under northern nursery conditions indicated that this insecticide has a half-life of at least 3 years, irrespective of medium composition. Dose-response tests of bifenthrin for controlling Japanese and oriental beetle larvae indicated that the LD₅₀ for these species is approximately 1.1 and 1.7 parts per million (ppm), respectively. These data suggest that >95% larval mortality of these scarab species can be expected up to three years following treatment of media with 10 ppm bifenthrin, and >99.9% larval mortality is expected for at least three years following treatment of media with 20 ppm bifenthrin.