Persistence of Foliar-Applied Insecticides for Elm Leaf Beetle Control, Trial Two, 1995
Abstract The mortality of elm leaf beetle larvae to foliar-applied insecticides sprayed on different dates was assessed. Three different insecticides were examined for differences in performance. Siberian elm foliage was treated with foliar-applied insecticides on each of 4 different dates. Treatments were applied with a pump-mister sprayer to the point of run-off. All foliage was collected and bagged on 24 Jul. In the laboratory, 10 larvae were placed in a petri dish and treated foliage was introduced for consumption. Mortality was assessed at 48 and 96 h after exposure by counting the number of dead, live, moribund and pupated larvae present in a petri dish at a given time interval. A few larvae in the petri dishes became infected with the fungus Beauvaria bassiana (Balsamo) Vuillemin and subsequently died during the course of the experiment. For this reason, only dead, uninfected larvae were used to calculate percent mortality estimates. The experiment was analyzed as a CRD with 8 replications per treatment.