Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2013
Publication Date: 4/17/2013
Citation: Valles, S.M., Porter, S.D., Choi, M.Y., Oi, D.H. 2013. Successful transmission of Solenopsis invicta virus 3 to Solenopsis invicta fire ant colonies in oil, sugar, and cricket bait formulations . Journal of Invertebrate Pathology. 113:198-204. Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. It causes economic losses that exceed 6 billion dollars annually in the United States and poses a threat to human health. USDA-ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) have conducted efficacy and bait formulation tests with the fire ant virus, Solenopsis invicta 3 (or SINV-3). The virus is being developed as a biopesticide as an alternative control method to chemical insecticides. SINV-3 was shown to be an effective control agent against fire ants in the laboratory when used in bait form. Water-based bait formulations of the virus were more effective than oil-based formulations. These results advance development of SINV-3 as a biopesticide for fire ants.
Technical Abstract: Tests were conducted to evaluate whether Solenopsis invicta virus 3 (SINV-3) could be delivered in various bait formulations to fire ant colonies and measure the corresponding colony health changes associated with virus infection in Solenopsis invicta. Three bait formulations (10% sugar solution, cricket paste, and soybean oil adsorbed to defatted corn grit) effectively transmitted SINV-3 infections to S. invicta colonies. Correspondingly, viral infection was shown to be detrimental to colony health and productivity. By day 32, all ant colonies exposed to a single 24 hour pulse treatment of SINV-3 became infected with the virus regardless of the bait formulation. However, the SINV-3 sugar and cricket bait-treated colonies became infected more rapidly than the oil-treated colonies. Sugar and cricket-treated colonies exhibited significant declines in their brood ratings compared with the untreated control and oil bait-treated colonies. Measures of colony health and productivity evaluated at the end of the study (day 47) showed a number of differences among the bait treatments and the control group. Statistically significant and similar patterns were exhibited among treatments for the quantity of live workers (lower), live brood (lower), total colony weight (lower), worker mortality (higher), proportion larvae (lower), and queen weight (lower). Significant changes were also observed in the number of eggs laid by queens (lower) and the corresponding ovary rating in SINV-3-treated colonies. The study provides the first successful demonstration of SINV-3 as a potential biopesticide against fire ants.