Insect Floral Visitors of Red Maple and Tree-of-Heaven at Potential Risk of Neonicotinoid Residue Exposure from Spotted Lanternfly Control

To manage spotted lanternfly (Lycorma delicatula (White)), an invasive planthopper recently introduced to the United States, governmental agencies, homeowners, and landscape professionals may treat its host plants with systemic neonicotinoid insecticides. Neonicotinoids can be harmful to non-target insect floral visitors collecting pollen or nectar. The insect floral visitors of red maple (Acer rubrum L.) or tree-of-heaven (Ailanthus altissima (Mill.), which are two of the preferred hosts of L. delicatula in Pennsylvania, are often targeted with neonicotinoid applications for control of this pest. To identify the floral visitors of these tree species, we conducted observations and collections of insects foraging on the flowers of these trees in Pennsylvania during the annual bloom period. In southeastern Pennsylvania, the margined leatherwing beetle (Chauliognathus marginatus (F.)). was the most dominant visitor of tree-of-heaven flowers, followed in abundance by bees, particularly Lasioglossum and Bombus spp., and flies. In central and southeastern Pennsylvania, bees were the most dominant group to visit red maple flowers, particularly Apis mellifera (L.), Andrena spp. and Osmia spp., followed by flies. These results contribute to our knowledge of the pool of bioindicator insects that may be at risk from exposure to neonicotinoid residues in flowers of trees treated for L. delicatula management.