Yellowjackets measure 5/8 to 1 inch (14-25.4 mm) long and have black and yellow markings in a bold pattern on the body. Since they are a type of wasp, they have 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 the workers will also forage on foods consumed by people, especially sweets and meats.
In the fall, yellowjacket colonies are at their largest size with many foraging workers. In areas with numerous yellowjacket colonies, foraging workers may become serious nuisance pests as they search for food. They often pester people eating outside and scavenge food from trash bins and dumpsters. In Virginia, yellowjacket wasps can be nuisance pests in recreational areas from late summer until early autumn, when colonies begin to die off.
TYPE OF DAMAGE
Yellowjacket workers will aggressively defend themselves and their colony by stinging if disturbed. 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, life-threatening reaction by the immune system.
Management of yellowjackets foraging in and around recreational areas is recommended to reduce the possibility of stings. Nests should be located during the day when workers are flying in and out on a regular basis. Mark the location of the nest and return late at night, after the workers have returned, to treat the nest with a liquid or dust insecticide. Destruction of individual colonies may not eliminate all the yellowjacket workers within a given area. This is because yellowjackets are capable of flying a mile from their colonies in search of food.
Effective management of yellowjackets in a given area can be achieved by rigorous sanitation and physical exclusion of foraging workers from attractive food sources. If begun early in the summer and carried throughout mid-autumn, proper sanitation will help reduce the buildup of foraging yellowjackets within an area. Lids of trash containers should be kept closed whenever possible. Open trash containers should be emptied regularly (every few hours when large numbers of yellowjackets are present). Use an aerosol insecticide to kill yellowjackets present around trashcans before emptying them to protect yourself from stings. Yellowjacket traps will catch some foraging workers, but will not completely eliminate the problem. Removing food sources and preventing workers from reaching food sources are more effective techniques in controlling foraging workers.
General spraying of an infested area is not effective, as new foraging workers will arrive from unsprayed areas. Also, electrocuting devices employing UV light (i.e., bug zappers) are of no value in reducing the number of yellowjacket foragers.
Yellowjackets completely abandon their nests each fall. A single queen starts a nest in a new location each spring.
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April 10, 2019