Lang Zhang1, Lei Wang2, Jian Chen3, Jianlong Zhang1, Yinghao He1, Yongyue Lu2, Jiacheng Cai4, Xuan Chen5, Xiujun Wen1, Zhiping Xu6, Cai Wang1. 1. Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China. 2. College of Plant Protection, South China Agricultural University, Guangzhou, China. 3. Biological Control of Pests Research Unit, Agricultural Research Service, US Department of Agriculture, Stoneville, MS, USA. 4. Department of Mathematical Science, Salisbury University, Salisbury, MD, USA. 5. Department of Biology, Salisbury University, Salisbury, MD, USA. 6. Shanghai Key Laboratory of Biological Chemistry, School of Pharmacy, East China University of Science and Technology, Shanghai, China.
Abstract
BACKGROUND: The red imported fire ant, Solenopsis invicta Buren, is a significant urban, agricultural, and medical pest with a wide distribution in the world. Surface or mound treatment using contact insecticide is one of the main methods to control S. invicta. In the present study, cycloxaprid, a newly discovered neonicotinoid insecticide, was evaluated for S. invicta control and compared with two referent insecticides, imidacloprid and bifenthrin. RESULTS: Surfaces or sand treated with cycloxaprid, imidacloprid, or bifenthrin caused high mortality of S. invicta workers, and the action of cycloxaprid or imidacloprid was slower than bifenthrin. Like imidacloprid and bifenthrin, cycloxaprid can be horizontally transferred from corpses or live donor ants to recipient ants. In addition, cycloxaprid- or imidacloprid-treated surfaces significantly induced the activities of acetylcholinesterase (AChE) and detoxification enzymes; nevertheless, they had no significant effect on the foraging behaviors of S. invicta workers. Also, sand treated with cycloxaprid or imidacloprid did not negatively affect the digging activities of ants. Interestingly, S. invicta workers excavated significantly more sand containing 0.01 mg/kg cycloxaprid than untreated sand in the no-choice digging bioassays. In addition, extensive nesting activities (sand excavation and stacking) were observed in the flowerpots containing untreated sand or sand treated with cycloxaprid or imidacloprid. On the contrary, bifenthrin significantly reduced the foraging, digging, and nesting activities of S. invicta workers. CONCLUSION: Cycloxaprid is a slow-acting and nonrepellent insecticide against S. invicta workers, and its contact and horizontal toxicities are slightly higher than imidacloprid.
BACKGROUND: The red imported fire ant, Solenopsis invicta Buren, is a significant urban, agricultural, and medical pest with a wide distribution in the world. Surface or mound treatment using contact insecticide is one of the main methods to control S. invicta. In the present study, cycloxaprid, a newly discovered neonicotinoid insecticide, was evaluated for S. invicta control and compared with two referent insecticides, imidacloprid and bifenthrin. RESULTS: Surfaces or sand treated with cycloxaprid, imidacloprid, or bifenthrin caused high mortality of S. invicta workers, and the action of cycloxaprid or imidacloprid was slower than bifenthrin. Like imidacloprid and bifenthrin, cycloxaprid can be horizontally transferred from corpses or live donor ants to recipient ants. In addition, cycloxaprid- or imidacloprid-treated surfaces significantly induced the activities of acetylcholinesterase (AChE) and detoxification enzymes; nevertheless, they had no significant effect on the foraging behaviors of S. invicta workers. Also, sand treated with cycloxaprid or imidacloprid did not negatively affect the digging activities of ants. Interestingly, S. invicta workers excavated significantly more sand containing 0.01 mg/kg cycloxaprid than untreated sand in the no-choice digging bioassays. In addition, extensive nesting activities (sand excavation and stacking) were observed in the flowerpots containing untreated sand or sand treated with cycloxaprid or imidacloprid. On the contrary, bifenthrin significantly reduced the foraging, digging, and nesting activities of S. invicta workers. CONCLUSION: Cycloxaprid is a slow-acting and nonrepellent insecticide against S. invicta workers, and its contact and horizontal toxicities are slightly higher than imidacloprid.