Update on the Efficacy of Selected Systemic Insecticides for the Control of the Asian Longhorned Beetle

two tests. In one test, twigs of silver maple were dipped in different concentrations of imidacloprid solutions. While in another test, twigs were freshly cut from treated host trees. In both cases, these twigs were provided to caged adults and the beetles were checked regularly for their mortality. The levels of imidacloprid in twigs were determined through chemical analysis. The LC 50 of imidacloprid for adult ALB is 1.9 ppm for a 3-day exposure. In 2003, to minimize the time that takes to inject and guard injected trees when imidacloprid is applied with the standard Mauget micro injection technique, and to compare officacy of imidacloprid with other neonictinyl systemic insecticides, we evaluated dinotefuran and thiamethoxam, and imidacloprid through different delivery methods for their efficacy for ALB and the standard Mauget Imicide. The three insecticides were compared using the delivery methods (checked) listed in Table 1. Mortality was checked for ALB adults caged with treated trees, and for wild beetles that migrated to and fed freely on treated trees. Five to 10 trees in each treatment group were dissected in October of the same year to check status of different stages such as egg, larva, pupa, and adult. The number of egg sites and exit holes were recorded. Mortality of adult beetles caged with treated trees was greater than the control for all treatments, except for soil injected and trunk implanted dinotefuran, and soil injected thiamethoxam. A possible reason for their lower adult mortality in treatments of tree implant and soil injection might be that beetles were caged soon after insecticide application. We know that translocation of imidacloprid is faster where trees are trunk injected versus trunk implanting and soil injecting. Speed of uptake This is an update of the study we have been doing in China to evaluate insecticides and delivery techniques for the control of the Asian longhorned beetle (ALB), Anoplophora glabrispennis. The following people and institutions have also contributed or participated in the study: Phillip A. Lewis, David R. Lance, and David M. Cowan from USDA APHIS CPHST, Otis Laboratory, and Baiying (city) and Jingtai (county) Forest Protection Station, Gansu Province, China. Our studies prior to 2003 involved cover insecticides and systemic insecticides. Different cover insecticides were tested for efficacy and persistency at different doses. Various systemic insecticides were tested for their efficacy for ALB control at different doses, application times and delivery methods. Several cover insecticides were tested in two different years with different application methods. In one test, the twigs of poplar trees were dipped into insecticide solutions and then provided to ALB adults, while in another test; twigs were collected from treated poplar trees and then provided to ALB adults. In both cases, generally, the tested insecticides showed good short term efficacy, but poor long term efficacy. Among the tested systemic insecticides (i.e., methamidophos, disyston, acephate and metasystoxr, imidacloprid, acetamiprid, thiamethoxam, and thiacloprid), imidacloprid and possibly thiamethoxam and acetamiprid can be used effectively to kill adult ALB beetles through soil and tree trunk injection. Significant mortality of adult beetles was observed 2 years after application with imidacloprid treatments. Mortality of ALB larvae, especially, late instars, however, was low. Residue levels of imidacloprid in treated trees and efficacy were limited by a number of factors such as delivery method, timing of application, tree species, and tree size. To establish the response of adult beetles to doses of imidacloprid, we also conducted