Evaluation of Systemic Insecticides in Protecting Container Grown Nursery Plants from Damage Caused by Field-Collected Populations of Redheaded Flea Beetle, Systena frontalis (Coleoptera: Chrysomelidae), Adults1

Systena frontalis (F.) is a major insect pest of nursery production systems in the Midwest, Northeast, and Southeast regions of the United States. Adults feed on plant leaves, which reduces salability of nursery-grown plants. There are limited options available to protect plants from S. frontalis adult feeding damage, and foliar insecticide applications are labor intensive. Systemic insecticides applied to the growing medium may protect plants from S. frontalis adult feeding. Consequently, in 2021 and 2022, we conducted two laboratory and two greenhouse experiments to determine if the systemic insecticides thiamethoxam, dinotefuran, cyantraniliprole, acephate, imidacloprid, and cyfluthrin thorn imidalcoprid protect plants from feeding by field-collected populations of S. frontalis adults. In the laboratory experiments, growing medium containing Itea plants was treated with the aforementioned systemic insecticides. Seven and 25 d after the treatments were applied, leaves were collected and placed into Petri dishes with a single S. frontalis adult. In the greenhouse experiments, Itea plants were placed into observation cages. Eight S. frontalis adults were released into each cage with an Itea plant. In the laboratory experiments, treatments associated with thiamethoxam and dinotefuran resulted in 100% mortality of S. frontalis adults after 72 h. In the greenhouse experiments, thiamethoxam, dinotefuran, and acephate protected plants from S. frontalis adult feeding 7 d after applying the systemic insecticide treatments. Therefore, systemic insecticides can mitigate feeding damage caused by S. frontalis adults on nurserygrown plants.