Bees and Wasps are Important
Bees pollinate important food crops, and honeybees provide people with honey. Wasps, although we usually think only about their stings, are also beneficial. They kill large numbers of plant-feeding insects and nuisance flies and feed them to their young.2,4 In addition, both bees and wasps have important ecological functions. Because of bees' and wasps' many benefits, entomologists, like those at Washington State University,2 advise leaving them alone "unless their stings present a hazard."2 It's sound advice! If bees or wasps are disturbing your picnics, or if a nest is too close to your home, there are a couple of things to remember. While they may appear threatening, many bees and wasps are not aggressive and will only sting when handled or stepped on. Most are beneficial to the environment and your garden.
If you'd like to do something other than reach for a spray can of poison to deal with stinging bees and wasps, you'll first need to correctly identify the insect and determine whether it's a threat. Each species has different behavior, and successful nonchemical management techniques are tailored to the particular species. If you decide that the bees or wasps need to be removed, be careful! These pests sting and can be dangerous if you are allergic to their venom.
Description: The most common yellowjackets in the Northwest are the western yellowjacket (Paravespula pensylvanica), the common yellowjacket (Paravespula vulgaris), and the aerial yellowjacket (Dolichovespula arenaria).1 The German yellowjacket (Paravespula germanica) is becoming widespread in Washington.2
Yellowjackets are about 1/2 inch long with jagged bands of bright yellow and black on the abdomen. The head and thorax are black with yellow spots and bars.3 They have a short, narrow waist4 and a broad abdomen that tapers off like a cone to a sharp point.3
Yellowjackets are the most commonly encountered wasp species and are sometimes called the "meat bee"4 because workers scavenge for meat or sweets at picnics and around homes.2 Females can sting repeatedly.3 They will land on people who are nearby and crawl inside their clothes5 and are extremely defensive when their nests are disturbed.3
Read the Yellowjacket page or the Yellowjackets factsheet for more information and tips for trapping and removal.
Description: Baldfaced hornets are nonaggressive yellowjackets.7 They are about 3/4 inch long with black and ivory markings on most of their body.8 They can have nests close to human activity all summer without being discovered or being a nuisance. Full sized nests are about the size of a basketball.7 Nests are pear-shaped and completely enclosed by a "paper" covering. The cells in which the larvae live are not visible.8
Control: Baldfaced hornets' nests are located above ground and can sometimes be removed without professional help.5 Hanging nests can be removed by placing a garbage bag over a wire hoop made from a clothes hanger. Hit the nest with a gloved hand, knock it into the garbage bag, and close the bag quickly. Then place the bag in the freezer to kill the hornets.5 Large nests may need to be removed professionally.
Although it may sound risky, you can use your own vacuum to remove hornet nests if you have an extension wand. Take a look at the hornets flying in and out of the entrance hole of the nest. Find the spot three or four inches outside the hole that all the hornets pass. When it is dark, or just before sunset, prop the vacuum extension so that its end is right at that spot. Run the vacuum for two or three hours. Repeat for four or five nights. According to Lane County (Oregon) bee removal specialist Tom Howell, you'll get phenomenal results.5
Howell cautions that you must not vibrate the nest and irritate the hornets. If they become agitated, turn off your flashlight so the stinging insects will not fly toward the beam of light and your body. It may be best to have someone else hold the flashlight so the person operating the vacuum can focus on staying cautious.5
Most of the hornets will die as they are sucked up the vacuum hose.5 After you turn the machine off, cover or stop up the end of the hose and leave the vacuum cleaner alone until all the insects have stopped buzzing. To make sure they're dead you can then put the bag in the freezer.
Description: Paper wasps are distinguished from yellowjackets by their long legs.2They are one inch long, have distinct, slender waists4. Many native species are golden brown with patches of yellow and red.4. The European paper wasp, first identified in the U.S. in 1981, has yellow and black markings that resemble those of yellowjackets.9
Native paper wasps are less aggressive than yellowjackets and rarely sting humans6unless their nest is located near doors, a fruit tree, or some other place where people are active.4 In protecting their nests, European paper wasps are more aggressive that native paper wasps and are alert to movement up to 20 feet away. Typically they will not attack unless a person is very close.9
Paper wasps hang their paper nests in protected areas such as under eaves, rocks, or tree branches, or in attics, exterior light fixtures and birdhouses.2,9 The nest hangs like an open umbrella from a stalk and has open cells that can be seen if you look up from below.4 The ends of the cells are open with the heads of the larvae exposed to view.7
Paper wasps, like yellowjackets, die when the weather gets cold, except for the overwintering queens.2 Native paper wasps do not use nests for more than one season,2 while European paper wasps may occasionally use a nest from the previous year.9
Control: Paper wasps can be left alone in many cases. Around doors and other busy areas, it's easiest to remove nests early in the season as the queen is starting to build her nest.9 The nest can be knocked down or hosed down. When nests are still small, they can also be vacuumed off at night when the queen and workers are home. Use a long extension wand on a shop vac that has few inchess of water plus a little dish detergent. Exercise caution when dealing with European paper wasps.
Description: Mud daubers are usually a single color, metallic blue or black.10 They are thread-waisted,10 solitary wasps.7 They do not defend their nests and rarely sting.10They build hard mud tube nests, usually under bridges, on walls, underneath eaves, or in attics.5,10
Control: Oregon bee removal specialist Tom Howell recommends leaving mud dauber nests alone because they are extremely docile, and there is only one per nest. He knows of only two people who have ever been stung by a mud dauber. "One of them sat on it, and the other pinched it," says Howell.5 If you feel that nest removal is absolutely necessary, remove nests in the early morning or evening when the wasps are not flying. Vacuuming can also be used to remove mud daubers.
Cicada Killer Wasps
Description: Cicada killer wasps cause alarm because of their size and the stingless male's habit of dive-bombing. Females reach 1 3/4 inches in length and males 1 1/4 inches.11 The eastern cicada killer has a striking pattern of black, yellow and red,11while the less bothersome western cicada killer is brown and yellow.12 Despite the threatening appearance, it's difficult to provoke one of these wasps into stinging.11
Cicada killers are solitary wasps, each having it's own burrow. However, large numbers of burrows may be clustered together on favorable sites. Cicada killers prefer to burrow on dry bare soil, sand, flower beds, and areas with sparse vegetation. Females also excavate nesting chambers and then go cruising for cicadas. She brings back her prey and drags it down into the chamber to serve as food for her offspring.11
Control: Cicada killers do not pose a stinging threat, so control is seldom required.11Their bothersome presence usually lasts less than two months.11 However, if wasp numbers are high or in a senstive area, the following tips can help with control and prevention. For a small number of wasps, eliminate wasps by swatting with a tennis racket or capturing in a butterfly net. Cover clustered burrows with a clear plastic tarp to prevent access and heat up the ground. In garden beds, a 3 inch layer of hardwood chips may deter nesting. Cicadas rarely burrow in dense, vigorous turf, so improve infested lawns by using appropriate liming, fertilization and watering.13 Mow high during nesting season.
Description: European honeybees are about an inch long with a black and reddish brown body covered with hairs. The female stings one time and then dies.3 Honeybees are usually not aggressive or threatening.6 Honeybees nest in many different kinds of places, but popular sites include inside chimneys or hollow trees, and in the walls of houses, barns, sheds and pump houses. Nests can also be found hanging from trees.5The nests are made of wax cells.3 Honeybees keep their hives at 95 degrees, so you may be able to actually feel their heat through the wall.14 The entire colony lives through the winter.3
Control: Honeybees are liberal in where they decide to nest and are happy to make use of a variety of different kinds of hive sites.5 Never attempt to remove or destroy a honeybee hive, and remember that honeybees are beneficial insects and are not usually threatening.6 If you decide you must remove a hive, it is necessary to get professional help. Hives can contain a huge amount of honey and wax. Because bees keep their honey cool by fanning it with their wings, removing the bees means that the honeycomb can melt, attracting more bees and insect pests.5
Description: The Africanized honeybee looks like a European honeybee, and like the European honeybee it stings only once.3 However, they are more defensive and less predictable. They defend a greater area around their nest and respond faster and in greater numbers than the European honeybee.15
Control: Welcome or not, these bees have made their way up from South America and are now present in some parts of the United States. Although the cartoons showing them swarming around and carrying innocent children away from recess are an exaggeration, they are more aggressive and more easily upset than typical honeybees.16
If you live in an area where Africanized bees are present, prevent problems by using the following tips:
- Eliminate potential nest sites (abandoned vehicles, empty containers, anything with a hole, old tires).16
- Inspect trees, garages, sheds, and fences regularly.16
- Fill all wall, chimney, and plumbing- related gaps that are larger than an eighth of an inch.16
- Cover rain spouts, vents, etc., with eighth-inch hardware cloth.
To prevent children from being stung by Africanized bee stings, warn them to respect all bees, and notify an adult if they find a nest or swarm.16
If you find a nest in or near your home, let professionals manage the problem,17 but ask them to use alternatives to conventional pesticides. In California, and perhaps other states, an insecticidal soap product, M-Pede, can be used by licensed pest control personnel to kill Africanized bees.
According to Oregon State University entomologist Mike Burgett, Africanized bees will not be a significant problem in the Pacific Northwest.18
Description: Bumblebees have round yellow and black bodies covered with fine hair.3They build their nests in the ground, under slabs, or in wall voids.14 They are not aggressive. However, the females can sting more than once.3
Control: Bumblebees are nonaggressive and can be good neighbors. Live with them whenever possible. If you must remove bumblebees, vacuuming (see above section on "Baldfaced Hornets") is effective. Because the entrance hole to bumblebee nests is often larger than with other stinging insects, it may be difficult to locate the spot in the air that all the bees fly past. You may need to make the hole smaller by using a piece of tape or a board to cover part of the hole. During the day, when the bees are active, turn the vacuum on. Continue to run the vacuum for two hours per day for about four days or until you do not see any more bees.5
Description: Carpenter bees are large and round like the bumblebee, but are totally black with a bald upper abdomen. They are solitary insects and build nests in tunnels in dead trees or wooden buildings.3 They can cause some damage to poles or other structures.7 They are not likely to sting unless handled, and have a surprisingly mild sting.3
Control: Carpenter bees are valuable pollinators and rarely cause severe damage.19"Prevention is the main approach to managing carpenter bees," according to the University of California Statewide IPM Project. "Fill depressions and cracks in wood surfaces so they are less attractive. Paint or varnish exposed surfaces regularly to reduce weathering. Fill unoccupied holes with steel wool and caulk to prevent their reuse. Wait until after bees have emerged before filling the tunnels. Once filled, paint or varnish the repaired surfaces. Protect rough areas, such as ends of timbers, with wire screening or metal flashing."19
Berry, R.E. 1978. Insects and mites of economic importance in the Northwest. Corvallis, OR: OSU Bookstores, Inc.
Akre, R.D. and A.L. Antonelli. 1997. Yellowjackets and paper wasps. Washington State University Extension. NOTE: A revised version (2003) is available at: http://cru.cahe.wsu.edu/CEPublications/eb0643/eb0643.pdf
University of Arizona. College of Agriculture and Life Sciences. Undated. Information sheet 20: Stinging insect identification tips.http://ag.arizona.edu/pubs/insects/ahb/inf20.html
Univ. of Calif. Statewide Integrated Pest Management Project. 2001. UC pest management guidelines: Yellowjackets and other social wasps.http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7450.html
Personal communication with beekeeper Tom Howell, Feb. 15, 2002.
DeAngelis, Jack. 1998. Urban entomology notes: Yellow jacket wasps. Corvallis: Oregon State University Extension.
Univ. of Idaho Cooperative Extension. Southern Idaho Entomology Programs. Bees, ants and wasps. http://www.uiweb.uidaho.edu/so-id/entomology/Bees,%20Ants,%20and%20Wasps.htm
Ohio State Univ. Extension. Undated. Ohio State University Extension factsheet: Paper wasps and hornets. HYG-2077-97. http://ohioline.osu.edu/hyg-fact/2000/2077.html
Jacobs, SB. 2008. Dominulus or European paper wasp. College of Agricultural Sciences. Dept. of Entomology.http://ento.psu.edu/extension/factsheets/dominulus-or-european-paper-wasp
Univ. of Calif. Vegetable Research Information Center. Undated. IPMinfo. Integrated pest management for the home environment: Wasps.
Sciarappa, WJ. 2004. The cicada killer wasp. Rutgers Cooperative Research and Extension. http://www.njaes.rutgers.edu/pubs/download-free.asp?strPubID=FS040
Bechinski, E and Merickel, F. 2009. Homeowner guide to minor stinging insects. Univ. of Idaho Extension.BUL 853.http://info.ag.uidaho.edu/pdf/BUL/BUL0853.pdf
Baker, JR, and S. Bambara. 2002. Cicada killer wasp. North Carolina State Univ. Cooperative Extension.http://www.ces.ncsu.edu/depts/ent/notes/O&T/lawn/note63/note63.html
Koehler, P.G. and D.E. Short. 2002. Stinging or venomous insects and related pests. Univ. of Florida. Cooperative Extension Service. Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/IG099
Univ. of Calif. Statewide Integrated Pest Management Project. 1998. UC pest management guidelines: Bee and wasp stings.http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7449.htm
Calif. Dept. of Food and Agriculture. Pest Detection/Emergency Projects Branch. 2000. Africanized honey bee: Fact vs. fiction.http://www.cdfa.ca.gov/PHPPS/PDEP/target_pest_disease_profiles/factVSfiction.html
Texas A&M Univ. Agriculture Project. Undated. What should I do about the Africanized bee?
Personal communication with Oregon State University entomologist Mike Burgett, June 3, 2002.
Univ. of Calif. Div. of Agriculture and Natural Resources. 2000. Pest notes: Carpenter bees. http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7417.html
Bees & Wasps by Cheryl Revell and Megan Kemple, NCAP