Stinging Pests May Be A Nuisance or Even A Health Threat
As the weather gets warmer, people spend more time outdoors. This is also the time of year when stinging pests are very busy looking for food and increasing their colony size. Although their presence and the threats they pose vary with your location, some of the most important stinging pests are baldfaced hornets, European hornets, paper wasps, yellowjackets, fire ants, and velvet-ants.
Baldfaced Hornets
These large, 5/8" to ¾" long, wasps are black with yellow markings which build large grayish-colored "paper carton" aerial nests, often as large as a basketball, which usually hang in an exposed location such as from a tree. Removal of their nests should be left to a properly trained and equipped professional.
European Hornets
These very large, ¾" to 1" long, hornets are brown with yellow abdominal stripes and a pale face. They build large brownish-colored "paper carton" nests, sometimes as large as a basketball, which are often located in some protected area, like a wall void, an attic, or within the branches of a bush. When their nest is in an exposed location, such as hanging from a tree branch of from the eave of a building, it is usually covered by several layers of brownish "paper carton." Although mainly active in the daytime, workers (and males) do fly at night and may be attracted to lights. They are generally beneficial insects, feeding mainly on other insects, many of which are pests of our plants. By late summer, a mature colony may number 200 – 400 workers (up to 1,000). Only fertilized queens overwinter. Workers are protective of their nest and give a painful sting, sometimes repeated stings, if they or their nest are disturbed. In general, they are much less aggressive, even near their nest, than are baldfaced hornets. Control of hornets or removal of their nests should be left to a properly trained and equipped professional.
Paper Wasps
Paper wasps, in the Genus: Polistes, are 5/8" to ¾" long, usually brownish with yellow markings. Some have red markings. They build a grayish-colored, single-layer, paperlike comb with cells opening downward. This nest is attached by a single long pedicel to a twig, tree branch, or horizontal surface, like an eave or window frame. They are beneficial insects, which are active in the daytime, feeding mainly on other insects, many of which are plant pests. A mature colony may number 100 – 250 workers. Workers are quite protective of their nest and will give a painful sting, often repeated stings, if they or their nest are disturbed. Control of paper wasps or removal of their nests should be left to a properly trained and equipped professional.
A recently introduced species, the Dominulus Paper Wasp, has spread throughout most of the Eastern U.S. Some workers of this species may survive the winter in the southern states, and they often will re-use and expand the previous year’s nest, which may get as large as a typical hornet’s nest after several years.
Velvet Ants
These are not true ants, but solitary wasps which parasitize other ground-nesting insects. The females are wingless and usually look very "fuzzy" because of their long, often bright red or orange setae. Females may run rapidly along the ground looking for their hosts’ nests or hunting smaller insects for food. Males are usually winged and may fly low or hover over areas of sandy soil where females may be found searching for their hosts’ nests. They may come into our homes or work areas during warm weather. They are considered beneficial, but they should not be bothered or handled. The females have a stinger which is very large (often ¼ the length of their whole body), and can deliver an extremely painful sting. Because of this they are sometimes called "cow-killers" or "mule-killers." Exclusion measures to keep them out of our homes are usually the only control measures needed.
Pavement Ants
If you find lines of small-to-medium sized (1/16" – 1/8" long), blackish ants, trailing along water pipes or utility lines which pass through walls, especially from the outside or even through interior walls, they are very likely to be Pavement Ants. Their average colony contains 3,000 – 4,000 workers, and has several queens. Outside nests are usually located under the edge of a large stone or a sidewalk (thus, their common name). They may nest in wall voids, in insulation, under a floor, or in ground-level masonry walls. Foraging trails may be 30 feet or longer from a nest. These ants will feed on nearly anything, but often show a preference for meats or greasy foods. They are not usually aggressive toward humans, but they sometimes bite and have a very painful sting as well. Workers of this species of ants are intermediate hosts of two different poultry tapeworms. The ideal way to control these ants is to find their nest and treat it thoroughly with a properly labeled insecticide, if the situation allows that to be done. Unusual structural situations, inability to find the nest(s), or customer concerns may require the use of baits. Baiting for any pest is very dependent on the pests’ accepting and feeding adequately on your baits.
Fire Ants
These ants get their common name from their very painful bites and stings. They are small (workers are 1/16" – ¼" long) yellowish-red to black ants, all in the Genus: Solenopsis, which are distributed from Virginia to Florida, and from Georgia to California. Workers of most species are several different sizes. They usually nest in the ground, but sometimes part (or a whole colony) may be located within a structure, usually in wall voids near heat or moisture (such as near a chimney or a bath trap). The two most important species are the Red Imported Fire Ant (RIFA), Solenopsis invicta Buren, and the Southern Fire Ant (SFA), Solenopsis xyloni McCook. Colonies of the RIFA may be as numerous as 30 to 100 per acre, with 80,000 to 250,000 ants per colony. They sometimes form multi-queen colonies which may be still larger. Mature queens may lay up to 1,500 eggs per day. Swarming may occur six to eight times per year. A typical RIFA colony mound is rounded, about 18" high, and about 24" across. Mounds have caused farm machinery to break, and farm animals have reportedly been killed by multiple stings (thousands) when they stepped into a RIFA mound. People usually develop a blister-like pustule at the site of a sting and true allergic reactions to fire ant stings can be life threatening.
Yellow Jackets
Yellowjackets are 3/8" to 5/8" long, depending on the species, with their respective queens being about 25% longer. Most species are black with yellow stripes, but some include red markings, and some are black with white markings. These are day-active, beneficial, predatory insects. They build a paperlike nest containing several layers of cells. A mature nest may typically have 2,000 – 6,000 cells and 1,000 – 4,000 workers. Nests are sometimes built in open aerial spots, or within bushes, but most species build their nest in a cavity hollowed out below ground. Some workers act as guards at the entrances to below-ground nests. They are very protective of their nest. Usually only fertilized queens live over the winter. Although yellowjackets are generally not likely to attack and sting humans, they can quickly become very aggressive if their nest is disturbed. After the new fertilized queens have gone into their overwintering sites, the remaining workers begin to seek sweets and garbage near places where humans are active outdoors, or around garbage cans. Workers can inflict a painful sting and may sting repeatedly. Yellowjacket control or nest removal should be left to properly trained and equipped professionals.