Yellow jackets

Overview

Yellow jackets are social insects in the paper wasp family. They are closely related to bees, wasps, and hornets and form colonies. Three species are found in Missouri: Eastern yellow jacket (Vespula maculifrons), Southern yellow jacket (V. squamosa), and German yellow jacket (V. germanica). The German yellow jacket is mostly found in the St. Louis area. Identification help.

Symptoms and Diagnosis

Yellow jackets are beneficial as they kill many harmful insects as they gather food for their young, but can be bothersome when they make their nests close to where humans work, relax, or play. They are attracted to overripe fruit, garbage, meat, and honeydew deposited on leaves by piercing-sucking insects. Humans are often stung when they happen upon a nest while working or playing in the yard or garden. When their nest is threatened they will attack aggressively and sting. Stings are painful.

Life cycle

Yellow jackets overwinter as fertilized females. In spring they establish a colony below ground in abandoned rodent tunnels, in protected hollows in trees, or behind walls of buildings. Being a member of the paper wasp family, their nests are constructed of paper but this is not evident in below-ground nests. Young are born throughout the season and the colony can grow to several hundred or even thousands of individuals by the end of the year. Only a few fertilized females survive past fall into winter. The nest is usually abandoned at the end of the season.

Integrated Pest Management Strategies

1. Just avoid the insects. If practical, just avoid the area where the insects have their nest. Left undisturbed they will not attack. If the nest is discovered in the fall, it will not be long until most adults die and the nest is abandoned. Rarely will the nest be used again next year.

2. Cover food and garbage. Since sweet drinks, overripe fruit, and garbage attract these insects, keep these items well covered or out of the open where they can attract yellow jackets.

3. Use traps. Commercial traps are available to trap the insects. Follow package directions.

4. Use a pesticide for colonies located in areas that pose a threat to humans spray with a commercial product labeled for wasps and hornets control. Treat at dusk or at night when the insects are in the nest. Stand 8-10 feet from the nest and spray down the hole until insects start to emerge. Then, walk away – don’t run. Repeat spraying each evening until complete control is achieved.

Organic Strategies

Strategies 1, 2, and 3 are strictly organic approaches. For an organic approach to Strategy 5, consult the Organic Materials Review Institute (OMRI™) for appropriate wasp and hornet insecticide products.