The field ant, or the formica ant as it is sometimes called, is a stingless ant species that often infests gardens in order to feed on honeydew. These ants are known for invading homes where they can become a serious nuisance, especially when they establish a colony within a home, which is not unusual. Although the field ant is largely a nuisance pest species that does not inflict stings like most other ants that are categorized as “dangerous”, they have strong jaws that can inflict painful bites. Even worse, these ants spray a defensive chemical when threatened. This chemical is known as formic acid, hence the field ant’s other popular name, “formic ants”. It is not uncommon for gardeners to sustain injuries to their hands and fingers due to a field ant presence within gardens. These injuries are often painful, but rarely medically significant. However, the irritation caused by contact with formic acid sometimes brings residents into the hospital ER.
Field ants are one of the most commonly encountered ant species outdoors in the northeast and other regions of the US. Perhaps the most significant problem these ants pose to homeowners is the nuisance they cause when swarming. Every fall these ants emerge in swarms from their underground nesting sites, which are sometimes located in residential yards. The large amount of winged field ants that emerge during the fall can be alarming and a nuisance to residents. For example, it is not uncommon for these ants to swarm outdoor get-togethers, and they can also swarm into homes. In addition to being a swarming nuisance, field ants also construct fairly large and unsightly nests in people’s yards. The base of their above ground nesting mounds can reach four feet in diameter, but when nests are located in lawns, the height of these mounds rarely surpasses the height of lawn grass. In other more secluded areas, these mounds can reach two feet in height. Field ants rarely enter homes on their own, but they frequently infest firewood that people bring into their homes. Field ants are most notable as pests for their outdoor mounds, which can make mowing your lawn a hazardous activity. The formic acid they spray in defense also kills grass and garden plants, resulting in patches of discolored lawn turf.
Have you ever mowed over an insect nest on your lawn?