Enhanced Pest Ant Control With Hydrophobic Bait*

The red imported fire ant, Solenopsis invicta (Buren), left most of its natural enemies behind in South America when it arrived in Mobile, AL, in the 1930s and spread rapidly throughout the southeastern United States, reaching population levels up to 10 times those found in South America. The large population densities and propensity for disturbed habitats led to direct conflict with human activities. Bait control methods were first developed for fire ants in the early 1960s and little has changed in the subsequent decades, despite the drawback that the bait carrier rapidly breaks down when wet. The southeast United States is wet; thus, bait labels have various guidance-restricting applications based on potential wet conditions. Here we compare a hydrophobic fire ant bait to the equivalent standard bait formulation and demonstrate in a paired-mound field experiment under natural wet conditions in Florida (heavy dew on ground), a significant advantage for the hydrophobic bait. An effective hydrophobic ant bait would extend the utility of current bait insecticides to wet conditions and also fill an important gap in our ability to control invasive pest ant species that thrive in wet tropical and subtropical habitats, e.g., Wasmannia auropunctata (Roger), the little fire ant.