The answer to 'why is my fire ant infestation' is that fire ants have likely infested your property and built mounds in your yard. Fire ants are aggressive, invasive insects that build complex underground nests and thrive in warm, moist climates. Some common causes of a fire ant infestation include improper lawn care, nearby construction, or the introduction of infested soil or plants.
Symptoms of a fire ant problem include seeing the distinctive mounds in your yard, getting bitten or stung by the ants, and observing large numbers of ants crawling around. Fire ant stings can be painful and cause swelling, and the mounds can damage lawn equipment and landscaping.