Ant Pest Control
Ants are one of the most common reasons Reno-area homeowners call for pest control, and one of the most misunderstood. More than 12,000 ant species have been described worldwide, and only a handful cause trouble in northern Nevada, but those few behave very differently from one another. A treatment that works well on one species can make another worse, which is why identification comes before anything else.
Ant Biology: Why a Colony Is Hard to Control
Ants are closely related to bees and wasps, and like them they are social insects that live in colonies divided into castes. Most of the ants anyone ever sees are workers: wingless females that forage for food, raise the young, and defend the nest. Queens lay the eggs and keep their wings until they mate. Winged males, sometimes called drones, exist only to mate.
An ant's body has three regions, the head, thorax, and abdomen, joined at a pinched waist called the petiole. The petiole carries one or two small bumps, called nodes, and counting them is one of the first things a technician checks, since it separates whole groups of species. Ants also have elbowed antennae. That detail matters in spring, when winged ants and termite swarmers are easy to confuse: a winged ant has a pinched waist, elbowed antennae, and front wings longer than its hind wings, while a termite swarmer has a straight waist, straight antennae, and four wings of equal length.
Ants go through complete metamorphosis. Eggs are tiny, about half a millimeter, and white. The larvae are legless grubs fed by the workers, and they molt through several stages before becoming pupae, which neither move nor eat. A single underground nest can hold 10,000 workers.
New colonies begin with a mating flight. Winged males and females swarm, mate in the air, and the males die soon afterward. Each mated female sheds her wings and starts a new nest underground. A swarm of winged ants around a window, or a scattering of dead ones on a sill, usually means an established colony is close by.
Diets vary by species. Some ants are omnivores, some eat mostly seeds and plants, and some hunt other insects. Outdoors, ants do useful work breaking down decaying material. The problems begin when they move into buildings: some contaminate food, some damage wood, some bite or sting, and a few can carry disease-causing bacteria onto kitchen surfaces.
Warning Signs of an Ant Infestation
- A large number of live ants in one area of the home, especially a kitchen or bathroom
- A trail of ants, often starting outside and leading in along a baseboard, pipe, or window frame
- Small piles of soil or fine debris marking a nest entrance in the lawn, along pavement, or at a crack in the foundation
- Dead ants, particularly winged ones, gathered on a windowsill
- Fine sawdust below wooden trim, beams, or window frames, the classic sign of carpenter ants
Catching an ant problem early is what keeps it small. A technician who finds the colony and identifies the species on the first visit can treat it directly, rather than chasing trails for months.
Ant Species Found Near Reno
Carpenter Ants (Camponotus species)
Carpenter ants take their name from tunneling into wood to build their nests. Unlike termites, they do not eat the wood; they excavate it and push the shavings out, so a small pile of sawdust near a wall, beam, or window frame is often the first sign of a colony inside a home. They can cause considerable damage over time, and they strongly prefer wood that has already been softened by water, which means finding them usually points to a leak around a roof, window, or plumbing line that needs fixing too.
They are the largest ant species in North America, 6 to 12 millimeters long, mostly black though some are dark brown. They forage mainly at night. Carpenter ants do not sting, but they can deliver a painful bite.
Harvester Ants (Pogonomyrmex species)
Two harvester ants are found in Nevada: the California harvester ant, 5 to 6 millimeters and red, and the western harvester ant, about 10 millimeters and dark red. They are herbivores that feed on seeds and other vegetation, and their feeding often leaves a bare patch of ground around the nest where nothing grows.
Harvester ants do not enter homes, but they are worth taking seriously in a yard where children and pets play. Their sting is painful, and in allergic individuals the reaction can persist for a long time.
Pavement Ants (Tetramorium caespitum)
The pavement ant is a small, 3 to 4 millimeter, blackish-brown ant that commonly invades homes looking for food. Up close, its legs and antennae are noticeably paler than its body. Pavement ants nest under sidewalks, driveways, and slabs, often beside lawns, and push small piles of soil up through the cracks. They usually come indoors in summer, but a nest close to the house can make them a year-round problem. Pavement ants are omnivorous and readily take grease, sweets, and pet food.
Pharaoh Ants (Monomorium pharaonis)
The Pharaoh ant is the hardest ant to control in our area. Workers are very small and yellow to reddish, and the colony nests indoors, in wall voids, behind baseboards, and near warmth and moisture. Pharaoh ants can form new colonies without swarming: when a nest is disturbed, queens and workers simply split off into several smaller colonies, a process called budding. That is why a store-bought spray so often makes a Pharaoh ant problem worse, turning one colony into several.
Pharaoh ants feed on pet food, syrups, and grease. They are also a serious problem in hospitals and care facilities, where they have been found feeding on patients' wounds, which is why they are treated as a sanitation risk and not just a nuisance. Slow-acting baits, not repellent sprays, are the standard treatment.
Thief Ants (Solenopsis molesta)
Thief ants are similar to the Pharaoh ant in size, shape, and color. They nest close to other ant colonies and raid them for food and brood, which is how they got their name. Indoors they go after grease, fats, and protein, and they are sometimes called grease ants for that reason; outdoors they are omnivores. Thief ants most commonly nest outside in soil or wood, and their mating flights run from July into early fall.
Acrobat Ants (Crematogaster species)
The acrobat ant is about 3 millimeters long, has two nodes on its petiole, and can be black, brown, yellow, or red. Its abdomen is sharply heart-shaped, and when threatened it raises the abdomen up over its body, which gives the ant its name. Acrobat ants move slowly compared with most species.
They feed on other insects, live or dead, and collect honeydew from aphids, mealybugs, and treehoppers. Acrobat ants nest in trees, stumps, and under stones, and occasionally move into damaged wood in a structure. When crushed, they give off an unpleasant odor.
Odorous House Ants (Tapinoma sessile)
The odorous house ant is small, 2.4 to 3.5 millimeters, with a soft body that ranges from brown to black. It occurs throughout North America and is very common in the West. It eats dead insects, sweets, and high-protein foods, and it nests outdoors or indoors in wall voids, often near hot water pipes. When crushed, it gives off a musty smell often compared to rotten coconut, which is the easiest way to identify it.
Odorous house ants tend aphids and mealybugs for their honeydew. A shrub carrying aphids that touches the side of a house can draw a colony straight to the building, so trimming vegetation back from the walls is part of controlling them.
Velvety Tree Ants (Liometopum luctuosum)
The velvety tree ant has a soft, almost velvet-textured body, 2.5 to 6 millimeters long, with a black head and abdomen and a red thorax. Colonies are very large and nest in trees or tree stumps. Velvety tree ants typically enter a home wherever a tree limb touches the house, and their trails can extend more than 200 feet.
They forage at night, feeding on honeydew from aphids and on other insects. They bite and apply a defensive chemical to the wound, and they produce a foul odor when crushed. A colony nesting inside a home excavates wood or insulation to expand its chambers, leaving sawdust that shows where the nest is.
Argentine Ants (Linepithema humile)
The Argentine ant is an invasive species introduced from South America. Workers are roughly 2 to 3 millimeters long, brown, and all the same size. They infest both landscapes and homes, and because they are strong foragers, their trails are easy to see. Argentine ants eat a wide variety of foods but prefer sweets, and in warmer months they rely heavily on nectar and on the honeydew produced by aphids and mealybugs, which they protect.
They are highly competitive and tend to become the dominant ant wherever they settle. Colonies have many queens and spread by budding, as groups of queens and workers move to a new site, and neighboring colonies connect into enormous supercolonies. Nests can sit in many places outdoors and in structural voids indoors, which is what makes Argentine ants so difficult to control once established.
Fire Ants
Two fire ants are of concern in Nevada, and both are mainly southern Nevada issues rather than Reno ones. The southern fire ant (Solenopsis xyloni) has a reddish-brown head and thorax and a dark brown to black abdomen. Its workers come in two sizes: small workers, called minors, about 1.6 millimeters, and large workers, called majors, about 5.8 millimeters. Southern fire ants are aggressive, sting painfully, and eat almost anything, including grease, live insects, seeds, and carrion.
The red imported fire ant (Solenopsis invicta) is 1.6 to 5 millimeters long and dark reddish-brown. It is a public concern because of its aggressive behavior and its sting, which can cause allergic reactions and, rarely, death. It also preys on the young of ground-nesting birds. The red imported fire ant is a quarantined pest, and moving it is prohibited by law. A suspected detection in Nevada is a matter for the Nevada Department of Agriculture, which handles treatment of the area, rather than a routine household call.
Ant Control
The first step is identifying which ant is present, since the right treatment depends on the species. The next is sanitation: cleaning up crumbs, grease, and spills, storing food and pet food in sealed containers, and fixing leaks, since moisture draws several species indoors. Trimming branches and shrubs away from the walls removes the bridges tree ants and odorous house ants use to get inside.
Most ant species nest outdoors, so a perimeter treatment around the foundation can keep them from coming in. Where the nest itself can be found, treating it directly gives the most complete control. Where it cannot, baits are the effective alternative. A bait combines a food the ant wants with a slow-acting insecticide, so foraging workers carry it home and share it through the colony, including with the queens. Baits take days to work, and spraying the ants feeding on them defeats the purpose, which is why baiting is the preferred approach for Pharaoh ants and other budding species.
B's Weed & Pest Control Services treats ants for homes and businesses throughout Reno, Sparks, and Carson City, as a one-time service or as part of a monthly, every-second-month, or annual plan.