FPL-Insects Carpenter Ants U of Nebraska 2004
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EXTENSION Carpenter Ant Lancaster County 444 Cherrycreek Road, Suite A / Lincoln, NE 68528 Management (402) 441-7180 / http://lancaster.unl.edu Barb Ogg, Extension Educator [004] Carpenter ants are important in though these two car- the balance of nature because they penter ant species have burrow and nest in dead trees and en- different coloring, they hance decay of the wood. They achieve both have one-segment- pest status when a colony invades and ed pedicel (the segment damages the integrity of the wood between the thorax and within a house. This fact sheet will the abdomen) and the explain how the biology and behav- profile of the thorax is Figure 3. Swarming queens Figure 4. Black ior of carpenter ants relate to control evenly rounded and not and kings have wings carpenter ant queen strategies when a homeowner is faced bumpy. All carpenter allowing them to fly and takes care of her first with this problem. ant species have these start new colonies. They lose brood herself. characteristics. their wings after mating. UNL Department Jim Kalisch, by Photos of Entomology Description and Habits Carpenter ant The black carpenter ant, Cam- workers are polymorphic—which 3). Swarming usually occurs during ponotus pennsylvanicus, is the most means workers are different sizes. warmer months, but in Nebraska, peo- common carpenter ant species in Entomologists refer to larger workers ple report swarms of the red carpenter Nebraska (Figure 1). Foraging work- as “major” workers and the smaller ant during warm spells in the winter. ers are black and quite large—1/4-5/8 workers as “minor” workers. The mi- Black carpenter ant swarms are more inches. There is at least one other car- nor workers are not “baby” ants—they commonly observed from March- penter ant species found in Nebraska. just have different tasks in the colony. June. The males are much smaller than Its scientific name is Camponotus sayi. Each colony has at least one queen, the the females and often emerge a few It has no recognized common name, egg-laying colony member. There may days earlier. but we unofficially refer to it as the be more than one queen in a colony. After mating, a single queen seeks “red” carpenter ant because it has a When a colony gets very large out a suitable nesting site and lays only reddish-orange head and thorax and a (6-10 years old and has more than a few eggs which hatch into mag- black abdomen (Figure 2). It is smaller 2,000 workers), it may produce winged got-like larvae (Figure 4). The queen than the black carpenter ant. Even reproductives, called swarmers (Figure Continued on next page � Graphics by Vicki Graphics by Jedlicka, Figure 1. Characteristics of the black carpenter ant Figure 2. Characteristics of the red carpenter ant Extension is a Division of the Institute of Agriculture and Natural Resources at the University of Nebraska–Lincoln Extension is a Division of the Institutecooperating of Agriculture with the andCounties Natural and Resources the United at theStates University Department of Nebraska–Lincoln of Agriculture. cooperating with the Counties and the United States Department of Agriculture. University of Nebraska–Lincoln Extension educational programs abide with the nondiscrimination policies Extension’s educationalof programs the University abide of with Nebraska–Lincoln the nondiscrimination and thepolicies United of theStates University Department of Nebraska–Lincoln of Agriculture. and the United States Department of Agriculture. cares for the larvae which become the colony’s first workers. These workers forage for food and take care of the colony while the queen continues lay- ing eggs. The diet of carpenter ants is quite varied and includes living and dead insects, honeydew from aphids, sweets, meat and fats. They do not eat wood. Workers leave the colony in late after- noon or early evening, forage during the night and return to the colony in the early morning hours. Carpenter ants carry food back to the nest intact or ingested and later feed it to non-foraging members in the nest. These ants may forage several hundred feet from the nest to search Figure 6. Incidence of carpenter ant damage in different parts of a typical for food. home. Homeowners may be concerned if they see carpenter ants inside. But, seeing carpenter ants inside the home does not necessarily mean the house is actually infested. It could mean the house is simply within foraging dis- tance of a colony. In the construction of their nest, carpenter ants hollow out dead tree limbs, logs, posts, landscaping timbers Barb Ogg, UNL Extension in Lancaster County Barb Ogg, UNL Extension Barb Ogg, UNL Extension in Lancaster County Barb Ogg, UNL Extension Figure 7. Rotted wood under window. Figure 8. Typical pile of sawdust discarded from carpenter ant tunneling. Sawdust won’t be seen ure 6 for most common problem areas in wall voids and other inaccessible of a home. Carpenter ants prefer to locations. nest in moist wood, but wood saturat- ed previously may be soft enough for carpenter ants to hollow it out. They Jim Kalisch, UNL DepartmentJim Kalisch, of Entomology may be a serious problem in poorly Figure 5. Smooth galleries of a maintained log houses (Figure 7). carpenter ant colony in structural Carpenter ants don’t always need lumber. a moist area to nest. They may use an old abandoned nest or wood “hol- and wood used in homes and other lowed out” by termites. Nests also may structures (Figure 5). They can also be located in hollow doors, small void UNL DepartmentJim Kalisch, of Entomology live in creosote-treated railroad ties areas produced during construction or Figure 9. Looking at carpenter ant because they don’t actually eat the even in foam insulation. sawdust with a magnifying glass wood, but only chisel it with their Carpenter ants keep occupied gal- shows tiny wood shavings all the mouthparts. Carpenter ant galler- leries clean. They remove wood in the same size, like tiny chisels were used. ies are smooth and very different form of a coarse sawdust-like material, It usually has insect parts in it. from termite feeding, which has mud which they push from the nest (Figure packed into the hollowed out area. 8). This often results in a cone-shaped Certain parts of a house, around pile accumulating just below the nest bits of soil, dead ants, parts of insects and under windows, roof eaves, decks entrance hole. This pile may include, and remnants of other food they ate and porches are more likely to be in- in addition to the wood fragments, (Figure 9). fested by carpenter ants. Refer to Fig- other debris from the nest, including Continued on next page Control Dust formulations registered for make sure the treatment worked. Baits. Colonies of some ant spe- use in and around the home include 3. Some companies have proposed cies can be controlled with baits, but Drione® (pyrethrins), Tempo® (cy- to inject insecticides into the soil pe- because carpenter ants have such a fluthrin), Deltadust® (deltamethrin). rimeter, similar to a termite treatment. varied diet, baits are not very success- These are marketed for the profession- This would be very expensive and is ful. als and not readily available in retail not recommended for carpenter ant Over the Counter Sprays. outlets. Another useful dust formula- infestations. Spraying foraging workers with most tion is Apicide® (carbaryl). It is a prod- Non-chemical Controls. insecticides is of limited value because, uct made to control bees and wasps Carpenter ant management involves even though some workers will die, in wall voids, but, because it is labeled eliminating moisture problems associ- the colony will largely be unaffected by for wall void treatments, it can be used ated with interior colonies to correct the treatment. for these situations. It is important to conditions suitable for colony survival. Treating the Colony. Because make sure these wall void treatments Colonies can sometimes be eliminated carpenter ants live in colonies, a treat- won’t come into contact with humans by discarding infested wood or by ment which targets the colony will or pets. Be sure to store any leftover vacuuming ants. In these situations, be most effective. Finding the colony insecticide in its original container no insecticides may be needed. is important. Look for the piles of with the label intact and throw away sawdust to locate the entrance. An- the make-shift duster so it doesn’t get other method to find the colony is to used around food. Prevention watch the movement of foraging ants. Transfer liquid insecticides. To prevent further carpenter ant They are most active at night. Inspect There are newer insecticides which infestations, trim all trees and bushes the entire structure and surround- do not kill insects immediately, but be- so branches do not touch the house ing grounds, because the nest may be come transferred to other members of and correct moisture problems such as outdoors. the colony. Termidor®, an insecticide leaky roofs and plumbing. Paint and/ Once you find the colony, control used for termite barrier treatment, has or seal exposed wood construction be- strategy depends on where it is. If the been shown to have this “transference fore it becomes wet. Replace previous- colony is in a tree, you can use a dust effect.” It is labeled for treating trails ly ant-or termite-infested wood, rotted insecticide (such as Sevin® or rote- and entry points where ants enter the or water-damaged wooden parts of none) labeled for use on trees in the home so it may be useful for some the structure and eliminate wood/soil landscape.