An Excerpt taken from the San Antonio Express-News Column GARDENING, ETC.
Copy for Sunday, July 15, 2001; Written by Nathan Riggs, Extension Agent - IPM (Bexar County Cooperative Extension)

Dealing with Paper Wasps and Yellowjackets

Summer means the peak season for many insects. Some are considered pests, while others are annoying to say the least. Some examples we'll talk about that hit close to home are paper wasps and yellowjackets.

As populations of webworms and other different types of caterpillars increase throughout the year, the populations of paper wasps and yellowjackets increase to feed upon the caterpillars. Although we traditionally think of wasps as the large, red insects that build paper nests on the eaves of buildings and yellowjackets as the yellow insects that do the same thing, they are actually two vastly different groups of insects. Wasps, more accurately called paper wasps, build paper nests that hang down from a short stem and can have many cells.

Paper wasps (Polistes spp.) can be red, brownish-red, orange, or yellow (with black stripes) in color with a body length of three-fourths to one inch and smoky wings, and their attitudes can be just as varied as their appearance. The darker-colored wasps are generally more aggressive in defense of their nest, while the yellow ones tend to be much more difficult to upset. Paper wasps feed on flies, caterpillars and beetle larvae and die out during the winter. Photos at left taken by G. McIlveen, Jr. (far left) and B. Drees (near left).

Yellowjackets (Vespula spp.), on the other hand, are much smaller (one-half inch long) and have black bodies with yellow markings and clear wings. In South Texas, the Southern Yellowjackets (Vespula squamosa) builds nests primarily underground that are encased in a paper "shell" that may be several layers thick. Inside there will potentially be thousands of cells tended by up to 4000 workers. Yellowjacket nests in East Texas have been unearthed that were over 6 feet across and contained over 1 million cells! Although they are ground nesters, they can construct aerial nests as well. Photo at right by G. McIlveen, Jr.

Yellowjackets feed on live insects (including webworms) animal carcasses, and food in garbage cans and picnic sites. They've even been seen eating dead insects from vehicle radiators! Yellowjackets survive over the winter in Texas. One last serious note regarding the Southern Yellowjacket: it's behavior when protecting the nest is virtually identical to the Africanized honeybee. It does not like lawn mowing equipment or visitors around it's underground home. If disturbed, yellowjackets can inflict multiple stings and will chase the source of the disturbance as far as 200 to 300 yards from the nest. If chased by these angry insects, run away in a zig-zag pattern, and seek shelter in a building or automobile. Do not jump in water...they WILL wait for you to surface!

Controlling wasps and yellowjackets is an individual decision based upon personal preference. Some prefer to preserve them while others cannot tolerate their presence. The optimum time to control wasps and yellowjackets is at night when they are calm and on (or in) the nest. Commercial long-distance aerosol sprays work fine against paper wasps as well as knocking down the nests to discourage them from a particular area. Yellowjackets, on the other hand, are easiest controlled by introducing one to two tablespoons of a dust insecticide into the nest opening at night. Use a red light to locate the nest opening because yellowjackets cannot see red light. One treatment usually is enough, but two or three applications are not unusual. Extension publication L-1828 on Wasps and Yellowjackets is a good reference on this subject.

Topics for this article are contributed and edited by staff from the Texas Cooperative Extension office in Bexar County. For more information, call (210) 467-6575.

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