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Uninvited Guests: Yellowjackets

Posted: July 16, 2012

With warm summer weather comes more outdoor activities, and the possibility of running into stinging insects like yellowjackets. Yellowjackets are actually a type of wasp that are often mistaken for bees. They can be quite aggressive,especially when their nest is disturbed, and unlike bees, they can sting more than once.
Yellowjacket

Yellowjacket

Some people have a severe or life-threatening allergic reaction to the venom released during a sting, so it’s important to prevent coming into contact with them as much as possible. Yellowjacket populations typically don’t reach large numbers until late summer. Depending on the species of yellowjacket, nests can be found in the ground, in trees, undervoids, and in the hollow spaces of children’s play equipment. Inspections and monitoring for the signs of a yellowjacket nest should begin in the spring and continue until after the first frost. Yellowjackets are roughly ½ to 1 inch in length with smooth looking bodies that are black with  bright yellow or white markings on the abdomen depending on the species. These social insects live in colonies with thousands of individuals in nests are made of a papery material, which may not be visible if the nest is in the ground. Yellowjackets can be aggressive and are especially a nuisance to humans because they scavenge in trash containers, on food and beverages eaten outside, and on ripe fruits and vegetables found in gardens and on trees. Although yellowjackets can be a pest, they can be beneficial to have in the natural environment. They are predators and feed on other unwanted insects such as caterpillars. If a yellowjacket nest is discovered but isn’t bothering anyone or causing a potential hazard, it can be ignored. If the nest is in an area where people are in danger of being stung, use IPM methods to address the problem:
• Begin looking for nests early in the season! Regular inspections of the building, grounds and play ground equipment can make managing a yellowjacket population much easier. New nests are easily destroyed.
• Make sure outdoor trash cans and dumpsters have tight fitting self closing lids. Use heavy gauge plastic trash bags inside garbage cans.
• Empty trash and recycling containers regularly. Wash and rinse out the container frequently, especially when food and beverages spill in the can or on the lid.
• Do not leave open soda cans or other beverages outside and then drink from them.
• Make sure window and door screens are in good shape. Place screening over ventilation openings to prevent yellowjackets and other insects from entering the building.
 
Because of the aggressive nature of yellowjackets, professional assistance is recommended for nest removal. If you are outside and yellowjackets are bothering you, don’t squash them. Many species will emit a chemical that alert other yellowjackets to attack.
 
For more information on yellowjackets, wasps and other stinging insects, go to http://extension.psu.edu/ipm/resources/pestproblemsolver/public-health. The publication Wasp and Bee Management: A Common Sense Approach is also a good source of information and can be ordered at http://palspublishing.cals.cornell.edu/.