Texas leafcutting ants

Texas leafcutting ants, Atta texana, are a native Texas species that create large, extensive colonies. Colonies often have multiple volcano or crater-shaped mounds with a central opening clustered in a single area.  Leafcutting ant mounds (see image) can be mistaken for fire ant mounds, but fire ant mounds do NOT have a centralized opening.

Workers are the most commonly seen leafcutting ants, but in spring it is possible to see reproductives, or swarmers.  Workers (see image) are medium to large ants, reddish-brown in color and have three pairs of spines on the thorax and one pair of spines on the back of the head.  Workers come in various sizes but can be up to ½ an inch long.  Reproductives look similar to worker ants but are much larger in size, with females being over an inch long. Mated queens have a special area within their mouth to carry fungal spores used to create a fungus garden in their newly founded nest.

Leafcutting ants typically forage when temperatures are cooler.  During this time of year, that can have them out in the middle of the day, but during the summer they tend to forage at night or in the morning. Workers remove leaves and buds from plants in the landscape; they then chew the plant material and get some nutrition from sap, but mainly place chewed leaves in an underground garden within their colony.  The chewed plant material is a base to grow fungus which the ants eat. Leafcutting ants tend a particular species of fungus and weed out any other fungus from their garden.

Colonies (see image) may exist for years and can exceed over two million ants.  It is not unusual for a single colony to cover an acre of land.  Colonies are usually found in well drained, sandy or loamy soils and are more common in Central to East Texas than other parts of the state.

Unfortunately, leafcutting ants can be difficult to manage, and almost impossible to eradicate completely.  Prized plants can be temporarily protected by using spray adhesives around the base of the plant, but adhesives need to be refreshed often when dirt and/or debris accumulates.  Temporary protection can also be provided to prized plants by utilizing contact insecticidal sprays or dusts labeled for “ants”.  These insecticidal products can also be used along foraging trails and openings where the ants go into the ground.  If mounds are present, Amdro Ant Block, which is the only product labeled for use against leafcutting ants, can be broadcast with a hand-held spreader around the mound area.  Do not use ant bait and residual dusts and/or sprays in the same area since pesticidal dusts and sprays will contaminate bait and cause the ants not to pick it up.

When managing leafcutting ants, set expectations at managing, not eradicating.  Often when you treat, you’ll knock back a portion of the worker population, but the colony will remain.

This work is supported by the USDA-NIFA Extension Implementation Program, project award no. 2024-70006-43508, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.