Field Ants

Facts, Identification & Control

Latin Name

Formica spp.

Appearance

What do they look like?
field ant picture

  • Size: Depending on the species, the size of the workers ranges from 4 to 8 mm.
  • Color: Coloration includes yellow, red, black or a combination of red and black.

How Did I Get Field Ants?

Field ants create mounds in open areas like lawns and meadows. They do not nest in homes but may come inside when swarming or searching for food. Inadequate weather stripping and cracked windows can let the pests indoors. Mounds built close to the foundation may also enable the ants to more easily enter a home. These are very large ants and are sometimes incorrectly thought to be carpenter ants.

How Serious Are Field Ants?

Field ant mounds can be three to four feet wide and up to two feet tall. The large nests affect grass growth and landscaping. When disturbed, field ants respond with a painful bite that, fortunately, does not have lasting effects. To remove a field ant mound, homeowners must get rid of the colony’s queen hidden deep underground, which can prove difficult. Other methods to control field ants include the use of liquid insecticides and solid bait granules.

How Do You Get Rid of Them?

What Orkin Does

The Orkin Man™ is trained to help manage Field Ants and similar pests. Since every building or home is different, your Orkin technician will design a unique program for your situation.

Keeping ants out of homes and buildings is an ongoing process, not a one-time treatment. Orkin’s exclusive A.I.M. solution is a continuing cycle of three critical steps — Assess, Implement and Monitor.

The Orkin Man™ can provide the right solution to keep ants in their place…out of your home, or business.


Signs of Field Ant Infestation

The activity of workers is an obvious sign. Considering the diversity of these ants, there aren’t many other common signs.  The most likely encountered types of field ants, sometimes called thatch ants, produce distinct mounds made of grass or other plant materials.

Behavior, Diet & Habits

Field ants encompass a large group of ant species belonging to the genus Formica.

Where do they live?
These ants make their nests in the ground in lawns, gardens, fields and parks. Field ants usually nest near trees, rocks, sidewalks, fences or foundations of buildings. Many species of field ants make a mound with the soil that they excavate under the ground. Sometimes people mistake these mounds for fire ant activity.

Some species of field ants, like the western thatching ant, Formica obscuripes (Forel), make mounds of leaves, grass, twigs or even pine needles. Others, like the California red-and-black field ant, Formica occidua (Wheeler) and the brown field ant, Formica cinerea (Mayr), make their nests in cracks of sidewalks or beside trees or foundation walls.

What do they eat?
Field ants eat honeydew. This is a sweet substance that they get from insects like mealybugs and aphids. They find the aphids on trees and shrubs. Some species of field ants, like the silky ants, Formica fusca (L.), keep herds of aphids so there is always a supply of honeydew. Field ants also eat other insects. Some field ants are attracted to meats. Many species of field ants are scavengers.

Do they bite?
The field ant, sometimes mistaken for the highly aggressive fire ant, is relatively docile in comparison. Field ants do not sting, but they do bite when disturbed. Some species can spray formic acid while they bite, which results in a painful experience. If victims experience symptoms, the effects are typically mild and subside in about an hour.

Always seek the advice and assistance of a physician if bitten or stung by ants.

Reproduction

Due to the diversity of the genus, it is difficult to make generalizations about reproduction since it varies somewhat between species. At a basic level the colonies consist of a queen who produces eggs. The eggs become workers who perform the necessary daily tasks of the colony.

Prevention Tips
Preventing field ant problems begins with a careful inspection. Look for things that the ants might use as nesting sites.

  • Place firewood on racks off of the ground and store it away from the house.
  • Move mulch away from the foundation to discourage ants from nesting.
  • Make sure exterior doors close tightly.
  • Replace weather stripping where it is missing.

It is advisable to contact your local pest control professionals. They will have the products and the equipment to control field ants effectively.