Evaluation of insecticides for suppression of Japanese beetle, Popillia japonica Newman, and crapemyrtle aphid, Tinocallis kahawaluokalani Kirkaldy.
Crapemyrtle aphid, Tinocallis kahawaluokalani, and Japanese beetle, Popillia japonica, cause extensive damage to crapemyrtle, Lagerstroemia spp., in both the landscape and the nursery. We evaluated foliar and systemic insecticides for control of these two important pests in a field trial in Griffin, Georgia, USA. Aphid control was also evaluated in a separate screenhouse trial on five cultivars (Dwarf Pink, Dwarf White, Pecos, Acoma and Hopi) of crapemyrtle. Talstar GH (bifenthrin), Scimitar GC (lambda-cyhalothrin), Merit 75WP (imidacloprid) and Flagship (thiamethoxam) were among the most effective of the eleven insecticides tested in the field trial for suppression of concurrent populations of aphids and beetles. Greatest reduction in Japanese beetle damage alone was evident with bifenthrin and lambda-cyhalothrin. Aphid numbers were lowest on plants treated with Orthene TTO (acephate), Merit 75WP and Flagship in the field trial and Flagship, Talstar GH and Scimitar GC in the screenhouse trial. Aphid numbers, among the five cultivars included in the screenhouse evaluations, were highest on 'Hopi' and lowest on 'Acoma'.