Wasps

Yellowjackets and paper wasps are beneficial insects. They feed their young numerous insects that ordinarily damage shade trees and crops. They also kill countless house flies and blow flies. Townsville pest management is available to help you eradicate your wasps.

A few species of yellowjackets, however, such as Vespula pensyl- vanica (western yellow jacket), V. germanica (German wasp), and V. vulgaris (common yellow- jacket), scavenge for meat and sweets and can become pests, especially at picnics and camp- grounds. Even though they may at times become pests, yellow- jackets and paper wasps are highly beneficial. Do not control them unless their stings present a hazard.

Life Cycle

Wasp pest controlIn the Pacific Northwest, yellow- jackets and paper wasps have annual colonies. The only colony members to overwinter are inseminated queens, which spend the winter in protected locations, such as under bark, in stumps and logs, and within stacks of fire- wood. The native Polistes aurifer (golden paper wasp) frequently overwinters in attics of homes.

The queens emerge during the first warm days of spring (as early as March and April), select a nest site, and build a small paper nest in which they lay their eggs. When the eggs hatch, the queen feeds the young larvae for up to 3 weeks. Larvae then pupate, to emerge as smaller infertile females called workers. Once the first five to seven work- ers appear, they begin rearing and feeding the brood. The queen rarely is seen again outside the nest. The colony then expands rapidly, and depending on the species, may consist of as many as 5,000 workers and 15,000 cells in the nest for some yellow- jacket species.

Colonies  attain  maximum  size in August and September. Worker yellow jackets, then at their peak,become pestiferous. About this time, new males and queens are produced from reproductive cells. These emerge and mate. The males soon die, and the inseminated queens seek sheltered locations in which to overwinter. The abandoned nests rapidly decompose and disintegrate during the winter. They are not used again. In spring, the cycle starts over.

The German wasp has become widespread in Washington. The cycle of this yellowjacket is slightly later, with peak colony size occurring in October and early November. This species has a propensity for nesting in structures and has become a wide- spread urban pest. Recently, the European paper wasp (Polistes dominulus) also has become wide- spread and abundant through- out Washington. It readily nests on and within human-made structures and is particularly populous in urban and suburban areas. The tendency of the German and European species to found nests in association with people contributes to their pest status.

Identification

wasp nest 1A typical yellowjacket worker, Vespula pensylvanica, is shown on the cover. Yellowjacket work- ers are about 1/2 inch long, and appear short and stocky.

All yellowjackets are yellow and black or white and black. Paper wasps are up to 3/4 inch long, and are more slender (see cover). Paper wasps may be distinguished from yellowjackets by their more slender body shape and longer legs. Although the golden paper wasp is easily distinguished from yellowjackets by its yellow and dark brown coloration, the newly introduced European paper wasp is quite similar in color pattern to yellow- jackets. Identification is important, because paper wasps are valuable as biological control agents of garden pests.

wasp nest 2Types of Nests

Yellowjacket nests are built entirely of wood fibers and con- sist of multiple stacked combs completely enclosed by a paper envelope, except for a small entrance at the bottom of the nest. Nests of most species are placed underground in rodent burrows or other soil cavities.

The German wasp, however, often makes its nest inside walls of houses. The aerial yellow- jacket (Dolichovespula arenaria) and bald-faced hornet (Doli- chovespula maculata) usually make their nests in trees or on the outside eaves of buildings.=

Paper wasps also build nests of wood fiber, but their nests consist of a single comb not enclosed by an envelope. An average nest of the golden paper wasp, the only paper wasp native to Washing- ton, consists of about 200 cells, while the largest nest is probably less than 400 cells. Golden paper wasp nests are most noticeable under eaves of buildings, but they are also constructed in logs, under rocks, within shrubs and grass clumps, and inside pipe.

Nests of the European paper wasp are often less than 100 cells in size but may possess 400 cells and more. This wasp appears to be quite flexible in selecting boxes, under eaves, chairs, and benches, and within shrubbery.

Control

Yellowjackets and paper wasps can be pests when they build a nest on or near your house. Yellowjackets may also be attracted in large numbers to food at picnics and to garbage cans. Various controls follow.

Select those most suitable for your needs. Remember, yellowjackets and paper wasps are beneficial insects control them only if only absolutely necessary.

Yellowjackets and paper wasps do not reuse their nests the following year, although paper wasps may construct a new nest adjacent to an old one. Knowing this may help you decide if you want to risk being stung during a control operation, especially

if the nest is in a rarely used area of the yard. If you choose to leave the wasps alone, the nest will usually disintegrate over the winter months. If the nest is on the eaves of the house or in an attic, it is advisable to remove it after the wasps are gone, because the nest may serve as a home of carpet beetles or other insect pests.

Nests

Aerial nests. Aerial nests are easily controlled using some of the newer aerosol products that propel the insecticide up to 20 feet. Effective materials to use are the synthetic pyrethroids, which have a quick knockdown effect. Apply in the evening after most yellowjackets or paper wasps have returned to the nest. Direct the initial spray stream into the hole or face of the nest, then thoroughly wet the entire nest. Do not attempt to remove the nest until you are certain that all wasps are dead. This may take a day or two, since some foragers do not return to the nest every night.However, when they do return, the insecticide residue should kill them rapidly.

Underground nests. Use a registered hornet and wasp spray. Direct the material into nest sites, including under roof shakes, within meter boxes, bird houses, outside grills, and mail the entrance hole after dark.

The aerosol formulation listed to kill aerial nests will rapidly kill subterranean colonies. After treating, do not plug the entrance hole. Returning foragers will enter the nest to be killed by the insecticide residue.

The aerosol formulations described under aerial nest control can also be used to kill  nests in wall voids. Consider calling a commercial pest control  operator to treat nests in attics  for safety  reasons.  Homeowners trying to treat nests in  close quarters like an attic are often badly stung or otherwise injured.

Traps. A number of types of water with detergent added. The yellowjackets will try to fly away with pieces of fish or liver that are too heavy for them, and will fall into the water, where the detergent acts as a wetting agent. Trapped yellowjackets, unable to fly, will drown. A cone trap can be baited with fresh or canned meat.

Safety Precautions

Yellowjackets and paper wasps may become aroused and attack in defense of their nest when disturbed. If you decide to remove or spray a nest, follow these precautions:

  • Cover yourself with thick clothing (including head, face, neck, and hands). lures and traps are available or can be made to reduce numbers of yellowjackets. Those commercial lures that possess heptyl butyrate are effective against  the western yellow jacket.
  • Other chemical lures generally attractive to most pest species are under development and might soon be commercially available.

Wet traps (traps that can hold a liquid) can be baited with soft drinks or juices.

For example, 50% apple juice in water is quite effective in attracting western yellowjackets and German wasps. Traps can be purchased or made out of a clear, 2-liter soft drink bottle. Cut the bottle one-third  of the way from the top, and tape the inverted top like a fun- nel inside of the remainder of the bottle.

Wear glasses to protect your eyes. Some species are capable of squirting venom for short distances and may target the face.

  • Spray or remove aerial nests during the coolest part of the evening, on a cool day if possible.

Suspended fish bait trap

  • Carefully put the pesticide into the entrance hole of ground nests after dark. They may fly towards the light from your flashlight.
    If you are allergic to wasp stings, do not risk removing the nest yourself. Some people react strongly to the stings of bees and Symptoms can include swelling, nausea, dizziness, difficulty with breathing, and shock. Symptoms may be immediate or delayed for several hours. For most people without allergies, a sting may be no more than a  minor annoyance or irritation at the time of the sting.
  • In late summer, paper wasps and yellowjackets are attracted to the odors from decaying fruit. Avoid wearing perfumes, hair sprays, or other strong scents when in areas with abundant paper wasps and yellowjackets. Also, avoid brightly colored clothing, particularly yellow, orange and red.
  • Restrain children and others from throwing objects at wasp nests. This not only agitates the wasps, but makes them more likely to attack upon future encounters.

Treatment of Stings

There are commercial preparations, such as a Sting-Killswab that can be used. Antihistaminic ointments and tablets, to be taken orally, seem effective in reducing reactions to stings.

People who are highly sensitive to stings should consider a desensitization procedure in an allergy clinic, and consult their physician about emergency kits which contain syringes with premeasured doses of aqueous epinephrine (for injection)  antihistamine tablets, and frequently a bronchodilator (inhaler), which may also contain epinephrine.

This content is sourced from https://ehs.wsu.edu/PH/pdfs/Yellowjackets%20and%20Paper%20Wasps.pdf