Integrating pest and pollinator management strategies for ornamental plant production

Key insect plant pests often require management because they can reduce the marketability and conservation value of wildlife friendly horticultural plants. Insect pollinators play a critical role in U.S. agriculture and local ecosystems, but insecticides used to control key pests can pose significant risks to them. Although pollinators include many insect taxa, most pollinator toxicological data focus on bee species. Lepidopterans (i.e., butterflies and moths) are also pollinators and important beneficial insects, but they can respond in markedly different ways than bees to the same insecticide. Furthermore, lepidopteran larvae (i.e., caterpillars) have different modes of exposure (e.g., leaf-feeding versus nectar consumption) and differences in susceptibility to insecticide target sites compared to bees. In fact, many insecticides are developed to have toxic effects on lepidopteran agricultural pests. Consequently, many products compatible with bee conservation are toxic or pose an unknown risk to larval lepidopteran pollinators. Using the monarch butterfly-milkweed-oleander aphid system, we conducted leaf and whole-plant feeding assays to evaluate acute and chronic effects of conventional and reduced risk insecticides on monarch caterpillars. We also tracked aphid densities on milkweed plants to identify insecticides that achieve pest control without compromising lepidoptera conservation. The results of this study will inform Integrated Pest and Pollinator Management (IPPM) strategies for ornamental plant production.