Efficacy of Soil Applied Neonicotinoid Insecticides Against the Azalea Lace Bug, Stephanitis pyrioides, in the Landscape

David W. Held, Shane Parker

Abstract


Azalea lace bugs (Heteroptera: Tingidae) are common pests of azaleas in the landscape and in plant production. Adults and nymphs feed on foliage causing stippling damage, which persists for multiple seasons. This study was conducted to determine the speed of translocation and residual longevity of various soil-applied neonicotinoid insecticides for control of azalea lace bugs in the landscape. Mass plantings of azaleas were treated with different formulations and application rates of clothianidin, dinotefuran, imidacloprid, and thiamethoxam. Treatments were evaluated at intervals of 3, 7, 14, 30 d, and 1 yr using a laboratory assay with excised shoots and field-collected adult lace bugs. A sample of field populations was taken 2 mo after the initial treatment. Plant health was determined by rating the severity of leaf injury and percent of damaged leaves per shoot. Dinotefuran and thiamethoxam provided the best control after 3 and 7 d in lab assays. A greater application rate improved efficacy of granular dinotefuran and thiamethoxam formulations in the 3-14 d evaluations. After 2 mo, azalea lace bug populations, primarily composed of nymphs, were lower than the controls. A laboratory choice test indicated that adult lace bugs do not avoid treated plants as has been shown for other sucking pests. After 12 mo, survival of lace bugs across all treatments averaged 61% and at least 1 product containing dinotefuran, thiamethoxam, and imidacloprid was significantly different from untreated controls. Plant appearance was also improved relative to untreated controls with fewer damaged leaves per plant on all treated plants after 1 yr.

View this article in BioOne

Full Text:

PDF