Abstract
DiapreORNAMENTALSpes abbreviatus (Coleoptera: Curculionidae), an introduced pest, has spread over a large area of central and southern Florida where it is damaging citrus, ornamental plants, sugarcane and numerous other crops. In addition to the damage caused by this pest, there are regulatory concerns of spreading Diaprepes to non-infested areas. This is particularly important in the ornamental industry because plants are shipped throughout the U.S. and abroad. Previous research has demonstrated that bifenthrin (Talstar) is efficacious against neonates and young larvae, and that some entomopathogenic nematodes are efficacious against various stages of larvae. Bifenthrin is currently recommended as a drench, or incorporated into the potting media, at a rate of 25 ppm based on the bulk density of the media. Tests were conducted to evaluate bifenthrin and entomopathogenic nematodes, alone and in combination, for control of older larvae (ninth instar) in ornamentals. In all cases, the combination treatment of bifenthrin and the entomopathogenic nematodes provided the best control, suggesting a synergy or additive effect between treatments. In a natural environment, the nematodes may be more efficacious against different aged larvae than the bifenthrin and therefore, improve control. The addition of nematodes may also provide a way to reduce the rate of insecticide currently recommended.
