Contact: Eric Day, Manager, Insect Identification Laboratory
Size: 5/8 to 1 inch (14-25.4mm)
Color: Black and yellow or black and white
Description: Yellowjackets are wasps with a definite waist. They fold their wings lengthwise when at rest. Like all wasps, yellowjackets prey on a wide variety of insects and other arthropods. Yellowjackets are unusual in that workers also forage on foods consumed by people, especially sweets and meats.
Habitat: Yellowjacket wasps are often pests in recreational areas in Virginia from late summer until early autumn.
Life Cycle: In the fall, wasp colonies have attained their largest size, and in the vicinity of numerous colonies, foraging workers may become serious pests as they search for food-usually food that is eaten or discarded by people.
Type Of Damage: If a colony is disturbed, worker yellowjackets will aggressively defend their colony by stinging. May create a nuisance and life-threatening stinging episodes. For most of us a sting may be just a temporary painful experience, but for allergic individuals a single sting may result in a serious reaction.
Control: Management of yellowjacket foragers: destruction of all yellow-jackets in and around a recreational area is advised to reduce the possibility of a dangerous sting. Nests should be located during the day when the workers are going and coming on a regular basis; the location of the nest should be marked. Return late at night to treat the nest with a liquid insecticide. The destruction of individual colonies may not eliminate all the yellowjacket workers from an area in which food is available. This is because yellowjackets are capable of flying a mile from their colonies in search of food.
Effective management of yellowjackets can be achieved by: (1) rigorous sanitation, and (2) use of physical exclusion from a food source. The principle behind these practices is the denial of attractive food to the foraging worker wasps. If begun early in the summer and carried out through mid-autumn, proper sanitation will help to reduce the buildup of foraging yellow-jackets in an area. Trash containers should be kept closed (lid) whenever possible; open containers should be emptied regularly (every few hours when a large number of foragers are present). Use an aerosol insecticide to remove yellowjackets present around trash cans in order to empty them. Place a 1/4 or 1/2 in. section of a no-pest strip to the inside of the lid of a closed trash container to kill the yellowjackets that may become trapped inside.
The following measures are of no value in reducing the number of yellowjacket foragers in an area: (1) general spraying of an infested area, and (2) electrocuting devices employing UV light, i.e., bug zappers.
Interesting Facts: Recent surveys indicate that between 0.5 and 1.0 percent of the population may be allergic to yellowjacket venom.
