Every time it rains, May through June, little mounds of dirt pop up all over the place. Everyone knows what they are, or they quickly (and usually painfully) figure out what those mounds contain. They contain fire ants, specifically the red imported fire ant (Solenopsis invicta). After being introduced to the United States through the Port of Mobile, Alabama in the 1950’s, the red imported fire ants started to work their way west and north. They arrived in the Dallas area in the late 1970’s through early 1980’s. When we hit our peak summer heat and dryness, and when we hit our brief winter cold temperatures, the red imported fire ants seemingly disappear. However, they are still present deeper in the soil, where it may be cooler, warmer, or there may be more moisture. During the spring rainy season as temperatures start to climb, saturated soils encourage them to move closer to the surface of the soil, and sometimes create really large mounds. During flooding events, they may create floating mats and get transported by water to new locations. Once the soil temperature hits about 84°, peak red imported fire ant activity occurs. This is when the fire ants are out actively looking for food. They are typically attracted to anything sweet, fatty or oily.
Red imported fire ants cause a variety of problems. The most obvious issue is also how they got their name; it hurts when you get stung. For most folks, it is a painful sting resulting in a small puss pocket. But some people do develop a strong allergic reaction to the stings, especially if stung by multiple ants at the same time. Being a non-native species, red imported fire ants negatively impact our native species both directly and indirectly. While foraging for food, fire ants are known to swarm newly hatched bird nests. Various baby mammals have been known to get stung. While it may not kill the baby animals, it keeps them more active which may attract the attention of predators. Red imported fire ants love soft bodied insects and worms, and tend to decrease the diversity of insects that may be found in an area. This in turn may weaken newly hatched birds by reducing the available food to newly hatched chicks.
So how does the Dallas Park and Recreation Department deal with fire ants in the parks? The department utilizes Integrated Pest Management (IPM) strategies that are ecologically sound, and ultimately reduce department’s overall chemical usage. Fire ants can not be completely removed from the parks but can be managed to reduce impacts to park users and park properties. Dallas Park and Recreation Department has Texas Department of Agriculture licensed pesticide applicators that utilize only EPA approved products to treat the parks for fire ants. Only those areas near recreation centers, sports fields, and actively used areas are actually treated for fire ants. Applicators utilize what is known at the “Two-step method”. A fire ant bait is broadcast once in the Spring, and then the mounds are treated as necessary. The department is increasingly utilizing organic means of treatment. Please keep in mind that many home remedy methods (grits, baking soda, vinegar, molasses, etc.) have not been scientifically shown to be effective. Treatments with citric oils may be good option, or they may simply encourage the ants to move. These are a few of the ideas the department is looking into in an effort to be more environmentally sensitive.
