Facts, Identification & Control
Vespula spp. and Dolichovespula spp.
Yellow jackets, genera Dolichovespula and Vespula, get their name from their yellow and black bodies. They measure 10 to 16 mm in length. Most yellow jackets are black and yellow, although some may exhibit white and black coloration. In contrast to the bee, the yellow jacket’s waist is thinner and defined. Their elongated wings are as long as the body and fold laterally when at rest.
Yellow jackets are wasps that can be identified by their alternating black and yellow body segments and small size. They are often mistaken for bees, although their bodies lack the same amount of hair, rounded abdomen, and the expanded hind leg used for carrying pollen of the bee. These social wasps live in colonies that may contain thousands of insects at a time.
Behavior & Diet
Yellow jackets are pollinators and may also be considered beneficial because they eat beetle grubs, flies and other harmful pests. However, they are also known scavengers who eat meat, fish and sugary substances, making them a nuisance near trash receptacles and picnics.
Many yellow jackets are ground-nesters. Their colonies can be found under porches or steps, in sidewalk cracks, around railroad ties or at the base of trees. Sometimes the queen uses a wall void of a building as a nesting place. Some yellow jackets build aerial nests in bushes or low-hanging branches or in the corners of buildings and other manmade structures.
A queen yellow jacket starts a new nest by building a small paper nest in which she lays the first batch of eggs. After hatching, these eggs are fed by the queen until they are ready to pupate and mature into adult yellow jackets. Adults live through one season and feed on caterpillars, grubs and other insects. They also enjoy nectar and sweet substances such as fruit and tree sap. Yellow jackets are attracted to garbage and other human foods, particularly meats and sweets.
A colony may contain 1,000 or more workers by fall. All of the workers are sterile females. In late summer males will begin to appear. When they become adults, they will mate with the females that will become the next year’s queens. The fertilized females will hibernate through the winter. The workers and the males will perish when the weather turns cold.
Signs of a Wasp Infestation
Yellow jackets usually are detected when workers are encountered. Nests, particularly the aerial nests, also may be a sign.
Yellow Jacket Stings
Known to be aggressive defenders of their colonies, yellow jackets are otherwise not quick to sting. The sting of a yellow jacket is painful, and each insect is capable of delivering multiple stings. Because they are equipped with lance like stingers with small barbs, compared to the larger barbs in honey bees, yellow jackets are capable of stinging repeatedly. Yellow jacket stings may induce severe allergic reactions in some individuals.
How Orkin Treats for Yellow Jackets
Since yellow jackets are beneficial predators of many damaging insects, treatment should only be applied when yellow jackets pose a stinging threat to people or pets. Therefore, a yellow jacket treatment program begins with a thorough inspection and correct identification from your pest management professional. This is important since yellow jackets usually build their nests below ground, but they may also build them in hidden, protected locations above ground. Once the nest is located, your pest management professional can use the most effective control products and methods to help eliminate control the yellow jackets within the nest.
The treatment products used by your pest management professional consist of various insecticide dust and aerosol products that will be used in accordance with the product’s label. The specific products and application methods will generally depend on whether the nest is above or below ground. For below ground nests, the most likely product of choice is an insecticide dust. The dust is applied to the below ground part of the nest and to the nest entrance. Since during the daytime there are numerous yellow jackets that are outside of the nest searching for prey, the nest entrance is left open so any returning nest members will come in contact with the product and die. For aerial nests, usually the use of either a dust or aerosol product is best. For aerial nests, your pest management professional may decide to perform the treatment work after dark when most all of the nest members are within the nest. Once the nest is inactive, it can be removed and destroyed.
Yellow jacket nests constructed in a void or cavity in a building’s interior presents a situation whereby the yellow jackets’ entrance must never be sealed until all of the nest’s yellow jackets are dead. If the entrance is sealed, members of the nest will try to escape the void through the inside of the structure and thus create a stinging hazard inside the structure.
Some of the preventive efforts that your pest management professional may recommend include keeping trash cans closed and clean so that yellow jackets are unable to feed on food residues either inside or outside the refuse container, keeping fallen fruit from fruit trees cleaned up and using specialized traps to capture yellow jackets that are attracted to the traps.