Factsheet: Wasp and Yellowjacket Control
Pest type: Insects
Wasps are beneficial insects that eat harmful insects and pollinate flowers. The most common species are the solitary and paper wasps, yellow jackets, and hornets.
Solitary wasps are thin- or thick-waisted, they visit flowers and other vegetation and are relatively docile. Their defining feature is that they will make nests in mud and soils and can be found by holes in the ground surrounded by piles of dirt. Yellowjackets and hornets on the other hand are stout, colorful, and mostly black and yellow or black and white. They are rapid fliers, aggressive, and capable of inflicting multiple stings.
They are also social, grouping in large colonies which they defend vigorously. Their nests are multilayered and built predominantly in the ground, although some aerial or in structures, with an outer papery covering called an envelope.
Finally, paper (umbrella) wasps have long bodies with thin waists and long dangling legs. They are social and search vegetation for prey, visiting flowers for nectar. They are not very aggressive. They too produce papery nests, but without an envelope and they are often attached to fences, eaves, boards, and branches. They are often shaped like and umbrella.
As stated above, some species of solitary wasps are docile, beneficial pollinators that should be left alone if possible. However, if yellowjacket, hornet, or paper wasp nests are found or if solitary nests are in a well-trod area, some control measures may need to be taken as these stinging and biting insects can cause severe injury even in people that are not considered “sensitive” to venom. Systemic (whole-body) allergic reactions to sting venoms occur in 1 to 3 percent of the population and cause about 50 deaths annually in the United States.
Wasps and yellowjackets are attracted to protein foods in the early months of summer, and sweet foods and drinks at the end of their life cycle. When a protein or sugar food source is generated by humans and readily available, it may be discovered early in the season by the queen, and the extra nutrients may be used to increase the size of her colony beyond what she could sustain on naturally available foods. Eliminating food sources will making it less inviting for wasps and yellowjackets to invade.
Additionally, nests tend to be underground, in hollow trees, or in the eaves, attics, and inside wall cavities of buildings. So inspect and repair the exterior surfaces of the structure, looking for cracks, splintered or rotten wood, holes in stucco or the foundation, unscreened vents, loose shingles, open plumbing cuts into the basement, and loose fascia boards. Duct tape, copper mesh, spackle, caulk, and cement patch are effective exclusion materials. Cover attic and crawl space vents with fine mesh insect screen. Seal open ends of fences with foam. During springtime, seal all holes in pipes and around screws with caulk or aerosol foam insulation in playgrounds.
Avoid wearing scents, such as perfumes, hair spray, suntan lotions, cosmetics, deodorants and shaving lotions. Don’t wear brightly colored, patterned clothing, but do wear shoes. Don’t squash wasps or yellow jackets it releases a chemical alarm that signals other wasps and yellowjackets in the area to attack. Use a lid and straw with soft drinks and juices; carry sugary or meat snacks in closed containers. Feed pets indoors or in a screened enclosure. Clean recyclables before storing them. Keep garbage cans clean and tightly covered, or seal all food garbage in plastic bags. Equip outdoor garbage cans with removable domed tops that have vertical, spring-loaded swinging doors or with spring-fitted lids. Periodically clean the lids of food wastes. Empty the cans frequently, especially during the most severe period of infestation, and monitor them daily, disposing of misplaced materials. Empty and clean dumpsters frequently. Dumpster lids should seal tightly and be kept closed when not in use. The area around the dumpster should be monitored daily, and all misplaced materials should be disposed of properly.
Spring is the best time for inspection. Nests are just forming and can be easily controlled. Don’t wait until fall! If there is a chronic problem with yellowjackets; inspect the area methodically to locate the nests. Nests can be found in the ground, under eaves and in wall voids of buildings. Ground nests are frequently located under shrubs, logs, piles of rocks, and other protected sites. Entrance holes sometimes have bare earth around them. Nest openings in the ground or in buildings can be recognized by observing the wasps entering and leaving. Inspect monthly to ensure that nests do not become large enough to be problematic.
Traps can be used to reduce wasp and yellowjacket populations and monitor the effectiveness of ongoing control programs. Baits, placed in the saucer or plate at the bottom of the trap (dog food, ham, fish and meat scraps early in the season, sugar syrups, spoiled fruit and jelly late in the season), attract the insects. Once flying in, they can’t escape. Commercially available fly traps are effective for wasp and yellowjacket control, with the appropriate bait.
Another method of destruction is physically removing the nest. However, any mass disturbance to a nest will trigger a mass attack, so hiring a professional is highly recommended if this is the route you choose. If you are daring, you will need special protective clothing to ensure your safety. Vacuuming can be effective, for nests in wall voids and underground. You should first consult a professional experienced in handling stinging insects. Use a lightweight, powerful vacuum with a removable bag that can be stuffed closed with cotton or a rag while the machine is running.
Vacuuming underground nests is a two-person job, with one person operating the vacuum and the other excavating the nest with a trowel. First check for auxiliary nest openings in a 40-to 50-foot area around the main opening, and fill any found with soil. Wear protective clothing. The vacuum should be held about 3 to 4 inches from the entrance of the nest so that the wasps are sucked in as they fly from the nest. Before the vacuum bag is full, vacuum up two tablespoons of cornstarch to incapacitate the wasps. Once the nest is empty, with no more wasps entering or leaving, dig out the underground nest structure. With the vacuum still running, open the canister and tape over the bag opening with duct tape. With the motor off, take out the bag and place it in a cardboard box. Seal the box and place it in a freezer at least overnight. Aerial nests and ground nest fragments that contain living larvae, should be placed in thick plastic bags and put in a freezer at least overnight.
Skunks, raccoons and badgers prey upon yellowjacket nests for the honey in the larval chambers. Drip honey over the entrances of nests at night when no one will be around the nests. In the morning, a helpful skunk or raccoon may have enjoyed a good meal and taken care of your nest for you.
Look at your product labels and try to avoid products containing those chemicals listed below:
(A = acute health effects, C = chronic health effects, SW = surface water contaminant, GW = ground water contaminant, W = wildlife poison, B = bee poison, LT = long-range transport)
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