In the Garden:
Upper South
August, 2003
Regional Report

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One of the most important means of yellow jacket control is by removing and disposing of fallen fruit, plus keeping garbage cans tightly lidded.

Beneficial Foe

Although ants and picnics are inextricably linked, yellow jacket wasps are another ubiqitous visitor wherever there is food or beverage outdoors, particularly in late summer. Gardeners also may stumble across their underground nests when weeding or mowing.

Other than trying to elicit their demise, I never really gave yellow jackets much thought until happening upon an article about them. It turns out that I need to appreciate them rather than just fear them. Yellow jackets are valuable scavengers and predators of insect pests, especially caterpillars. So to prevent undue ecological harm, it's important to learn how to live with these creatures.

A typical yellow jacket worker is about 1/2 inch long, with alternating black and yellow bands on the abdomen. The queen is about 3/4 inch long. They have well-developed mouthparts for capturing and chewing insects and a tongue for sucking nectar and juice from fruits. There are over a dozen species found in North America.

Yellow jackets are distinguished from honeybees by the tan-brown dense hair and flattened hairy hind legs on the bees. On a more up-close and personal level, a yellow jacket is more aggressive and does not have barbs on its stinger. It can repeatedly insert it into a victim, while a bee can only sting once.

Yellow jackets are considered social wasps because they live in organized colonies. They are annual insects with only the fertilized queens overwintering in a protected place, such as under bark or in hollow logs. In the spring, the queen selects a nest site and begins laying eggs. The colony expands as the queen keeps laying eggs, and the papery nest takes on multiple comb layers. By the end of summer, a colony may contain as many as 4,000 workers. Nests can be in or on human structures or built in underground burrows abandoned by rodents.

Adults feed primarily on items rich in sugars and carbohydrates, such as fruits, flower nectar, and tree sap. The larval stage feeds on proteins, such as insects, meat, and fish, brought to them by the adults.

Sting Prevention and Treatment
Other than staying indoors, the best way to avoid wasps or bees is to wear no perfume or perfumed products and plain light colored clothing. But if you spend any time at all outdoors, a yellow jacket will inevitably cross your path. Do not start waving your arms or running, as quick movements often provoke an attack. Instead, very slowly raise your arms to protect your face, remain stationary for awhile, then very slowly move away. Crushing a wasp against your body can incite nearby ones to attack as the venom contains an alarm pheromone that signals other wasps.

If you are stung, immediately apply a poultice of a meat tenderizer. Antihistamine ointments also are effective. A small percentage of the population is hypersensitive to wasp or bee stings. If you don't know if you are among them, go to an allergist for testing. People who know they are hypersensitive should always have a medical kit for stings readily available when outdoors.

Control Measures
Since yellow jackets do play a beneficial role in our ecosystem, the objective of a management program should be to reduce their habitat, particularly near areas where people congregate. When eating outdoors, keep food covered. Keep refuse in containers with tight-fitting lids. Pick fruits as they ripen and remove any fallen fruit rotting on the ground.

If you need to eradicate a nest, use an insecticide containing pyrethrins or carbaryl (Sevin). For nests below ground, treat after dark with an insecticidal dust, then cover the entrance hole with a shovelful of soil. For nests above ground, treat during the day, using an insecticide in a special pressurized can that emits a long, narrow spray 15 to 20 feet. First spray in a sweeping motion around the nest, then direct the spray into the entrance hole at the nest bottom.

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