Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: May 29, 1996
Publication Date: N/A
Interpretive Summary: The fire ant is an agricultural and medical pest in the southern and southeastern United States. It was accidently imported into this country in the 1930s. Its painful sting, aggressive behavior and large numbers have allowed it to dominate the native ant fauna and create a profound negative effect on the ecology of infested areas. Toxic baits are preferred for fire ant control because they require less toxicant for control, but these also affect non-target ant species. Non-target ants are good predators of newly mated fire ant queens and if left unaffected could slow reinfestation. This report focuses on the use of fire ant worker attractant pheromones to enhance the effects of currently available bait toxicants. We have used a worker attractive component of the queen recognition pheromone, invictolide, to test the effectiveness of pheromone enhanced baits. Our results demonstrate that pheromone enhanced baits are discovered significantly faster than non-enhanced baits. In addition, the pheromone attractant helps the fire ant worker find a higher percentage of the bait particles, which are concealed in a complex three dimensional foraging area, e.g. a pasture. Therefore, more active ingredient reaches the target colony. Thus, pheromone enhanced baits have the potential to better control fire ants and/or allow for a reduction in the amount of insecticide needed to control colonies. In addition, if the fire ant retrieves more bait particles, then there will be fewer bait particles available for non-target ants to harvest. This could result in slower reinfestation rates. A patent application has been filed based on this technology.
Technical Abstract: The utility of pheromone enhanced ant baits was investigated using fire ants as the model organism. The enhanced bait consisted of hydramethylnon (active ingredient, AI), soybean oil (phagostimulant and AI solvent), defatted corn grit (carrier), and "invictolide", a component of the fire ant queen recognition pheromone. The major hurdles that had to be overcome in this work were the many variables in the field that contributed to the high variance in bait efficacy, which makes detection of differences between standard and treatment difficult. Consideration of these variables was essential in this work. The enhanced bait was discovered almost twice as fast as standard bait particles. In addition, controlled field studies using single mound treatments demonstrated that besides being discovered faster, more active ingredient was getting to each target colony, because more bait particles were discovered. Thus, this work has demonstrated that pheromone enhanced ant baits offer several advantages over standard baits, especially the potential reduction of insecticide usage. Opposing these advantages are considerations for commercialization, among these are shelf life and the economics of the new pheromone enhanced formulation.