Unlike the tropical fire ant, red imported fire ants have multiple queens in their colonies and therefore produce more eggs and brood, French said. They are a big problem in citrus orchards because they swarm onto and sting unsuspecting citrus workers, and because the ants can kill young citrus trees. They get under freeze protection foam tree wraps, out of a grower's sight and can completely girdle a tree, which cuts off the nutrient flow. For years, growers had only Lorsban, a liquid drench that kills on contact, to treat for ants on producing citrus. But now they have a product called Clinch that is formulated in a granular bait of corn cob grit and soybean oil.
Worker ants carry the bait to the queens that eat it and become sterile or die.
These ants disrupt that balance. Distinguishing the red imported fire ant from the tropical fire ant is difficult. Their mounds, however, are easily distinguishable. The red imported fire ant has a higher, dome shaped mound that over time becomes encrusted, or hardened. The mound of a tropical fire ant is a flatter, soft-textured structure that covers a wider area.