Leaf cutting ants are rust to dark-brown in color, and vary greatly in size.  Worker ants range from 1/16 to 1/2 inch long.  The queen is about 3/4 inch long. Leaf cutter workers can be distinguished from other ants by their three pairs of prominent spines on their back (thorax) and one pair of spines on the back of the head.   The queen rules the colony from her underground chambers.  Colonies may have as many as four or five fertile queens, each of which continually produce eggs.  Eggs develop into cream-colored larvae that become 1 /4 to 1/2-inch long when fully developed.   Most larvae develop into sterile female workers ants; however, in the spring, some of the larvae develop into winged males and females.  These reproductive ants can number into the thousands.  They are distinct from worker ants, being several times larger, that they are often not recognized as the same species. They are dark, rusty brown with have long, black wings. Females can be distinguished from males by their larger heads.

LIFE HISTORY AND HABITS
      Mating flights of Texas leaf cutter ant reproductives take place on clear, moonless nights during April, May and June.   In areas of higher rainfall, swarms can occur at any time during the spring; however, to more arid areas swarms invariably occur after a heavy rainfall.  Prior to her nuptial flight the virgin queen stores a small portion of the fungus garden in a small cavity inside her mouth.  After mating the winged males die, while mated queens drop to the ground, lose their wings and attempt to establish small nests beneath the soil.
        After digging a small gallery in the soil, the queen takes the fungus wad from her mouth and begins to culture it as food for her first eggs. Initially the fungus is nourished by fecal material. Approximately 90 percent of this first brood will be eaten by the queen. The first worker ants will be quite small because of their limited food intake; however these first workers bring back leaf fragments to enlarge the fungus garden, thus providing more food for later broods. As the colony grows, worker ant size increases.
        Individual colonies can exist for years.   Where adequate food is available, colonies may expand to contain over 2 million ants.  Leaf cutting ant colonies are frequently seen along roadsides, in open fields, in brush land or forestland.  The colonies are restricted to deep, well drained sandy or loamy soils.  They can be quite large, covering an area up to almost an acre.   Colony size depends on its age and the availability of food.  In heavily infested areas it is difficult to distinguish where one colony ends and another begins.
        Above ground, the colony is marked by numerous crater-shaped mounds, 5 to 14 inches-high and up to 1 to 1'/z feet in diameter. Each mound has a central entrance hole.   Above the underground central nest cavity, several entrance holes will be marked by typical crater shaped mounds and a buildup of soil. On flat land, this buildup of soil is very apparent.  With older colonies, this central area is as much as 2 to 3 feet higher than surrounding land. Below ground, the nest consists of several chambers that may reach 15 to 20 feet deep.  All chambers are interconnected by narrow tunnels. Vertical tunnels extend to mound openings, and lateral foraging tunnels may lead outward 500 feet away.  These lateral exits are commonly referred to as "feeder holes".  The complex structure of the cavities and tunnels allow the ants to escape predators underground, and provide an efficient air circulation system.   Coincidently, the large complex nest structure makes control with insecticides difficult.
        During the summer, leaf cutting ants forage almost exclusively at night.  The rest of the year, foraging takes place during the day, when air temperatures range between 45 to 80 degrees F.  Most mound building activities occur during the cool hours of the day.  Leaf cutting ants are usually inactive on cold, wet or cloudy days.
        On the soil surface leaf cutting ants have clearly defined foraging trails.  Ants commonly travel 600 feet or more to reach a suitable plant. Once located, the plants are attacked in large numbers, with worker ants cutting leaves and carrying the fragments in their mouths (mandibles).  Leaf fragments are carried umbrella-like, over the head--hence the common name, "parasol ant".  Hundreds of ants can be seen picking up and carrying off the piles of leaf fragments that accumulate under the trees or bushes "under attack."   At the nest entrance, ants chew the fragments into small pieces that are better suited for their underground fungus gardens.

DAMAGE SYMPTOMS
      Defoliation by leaf cutting ants can resemble damage produced by several other leaf chewing insects, particularly sawflies and leaf cutting bees. Trees defoliated by the leaf cutting ant usually are within sight of an ant nest and the ants themselves may be seen carrying leaves. Foraging trails will be littered with pieces of leaf tissue that can be traced to a feeder hole. Considerable damage to a plant can occur in a few hours. Small- to medium-sized trees can be stripped in one night. One researcher in South America estimated that a large leaf cutting ant colony harvested approximately 13,000 pounds of leaves over a 6-year period. This same colony excavated 802 cubic feet of soil weighing over 44 tons.

CONTROL
      Control of Texas leaf cutting ants is difficult. Although plants can be protected temporarily using powder or granular formulations of contact insecticides like acephate (Orthene®), diazinon or chlorpyrifos (Dursban®), these treatments must be reapplied frequently. Also, plant applications do not eliminate underground colonies. The large size and complexity of leaf cutter ant nests makes it difficult to obtain good control with dust, liquid and granular insecticides. A special formulation of hydramethylnon, Amdro® Leaf-Cutting Ant Bait was manufactured in 1995, but any material currently on shelves is likely to be unattractive to foraging ants, and thus ineffective. Because these ants eat only the fungus they cultivate, they do not respond to most other ant baits. More recently, a new product called Volcano® leaf cutter ant bait has received label approval for control of leaf cutter ants in forest areas. Volcano® is not currently labeled for use around the home or in urban environments.
        The most effective treatments currently available to consumers include acephate dusts and insecticide granules labeled for ant control. These products should be applied to all nest openings according to label directions. If possible, dusts should be blown into nest openings. It may be difficult to obtain complete control of large, well-established colonies using these products.
        Methyl bromide gas (Brom-O-Gas®), is a highly toxic, RESTRICTED USE pesticide that is currently the only product specifically registered for control of leaf cutter ant colonies. Fumigation with methyl bromide should attempted only when the colony is located away from human dwellings. Methyl bromide gas is highly toxic to humans, animals and plants. Fumigation with methyl bromide should only be done by trained, licensed and skilled pest control professionals. All uses of methyl bromide are currently being phased out by the U.S. Environmental Protection Agency, so the availability of this product is limited.

SAFETY FIRST
        Before using any chemical, READ THE LABEL and follow all instructions and safety precautions. Avoid chemical contact with skin. Wash exposed areas with generous amounts of soap and water. Store chemicals away from human dwellings in locked cabinets and out of reach of children and pets.