Evaluation of Chemical Control Strategies for Linepithema humile (Mayr) (Hymenoptera: Formicidae) in South Carolina State Park Campgrounds1

The Argentine ant, Linepithema humile (Mayr), is a pest in many urban areas of the southeastern United States. In the Piedmont region of South Carolina, there is a documented problem with L. humile invading the campsites of state park campgrounds. While some parks have tried to implement proactive control programs, the most widely used tactic is spraying insecticides when L. humile populations become intolerable and visitors complain. For this study, a series of four trials were conducted to evaluate insecticidal spray treatments versus combinations of insecticidal sprays and granular bait. Control areas were set up to evaluate the change in ant foraging numbers over a season without chemical interference. One bait (Niban® Granular Bait) and three insecticidal sprays (Premise® 2, Temprid™ SC, and Tempo® Ultra SC) were evaluated to determine the best option in a park setting. The granular bait did not perform as well as the liquid insecticides. Temprid™ SC and Tempo® Ultra SC both resulted in a decrease in L. humile over the four-week period that was not significantly different. Although both insecticides were comparable in results, we found Tempo® Ultra SC to be the best choice in this study due to its lower cost and lower toxicity to non-target organisms. Assessing different methods of chemical management will enhance future efforts at sustainable control of L. humile in campground environments.