A bounty was compensated in New Zealand for each German yellowjacket queen collected in the springtime to the Department of Agriculture. The mass destruction of overwintering queens had virtually no effect on yellowjacket populations the following summer. (Even when 99.9% of the potential queens were eliminated, the same number of annual colonies would remain.)
Homemade Yellowjacket Traps
Hang fish or liver suspended on a string one to two inches over a tub of water to which detergent has been added (wetting agent eliminates surface tension). Yellowjackets will attempt to fly away with pieces of fish or liver that are too heavy for them and will drown after falling into the water. It isn’t unusual to fill a dishpan with drowned yellowjackets in one afternoon during the peak season.
Trapping big numbers often fails to reduce population to acceptable levels, but could be useful in small areas. Certain yellowjackets have been shown to fly from 300 to 1,000 yards from their nest in search of food.
Commercial Yellowjacket Traps
There are a few commercial non-toxic bait traps for yellowjacket wasp control. It’s important to know that no trap is good at rapid knockdown of yellowjacket populations. For effective use at outdoor events, traps ought to be placed out two or more days prior to the event.
Approximate trap costs are –
• Green Leaf Wasp EATER Trap – $7.99 to $9.99
• Oak Stump Farm “Yellowjacket” Wasp Trap – $7.99 to $8.99
• Consep Wasp Trap – $6.95 to $7.99
• Yellow Jacket Inn – $4.99
• Victor Flying Insect Trap – $2.95
Every trap except the Yellow Jacket Inn relies on exhausted yellowjackets dropping into the liquid bait and drowning before they can escape back out the entrance holes.
The addition of a drop or two of liquid dish soap to the bait after it has been poured into the trap is critical. (Soap lowers the surface tension of the liquid bait and enhances drowning.) Some apply a thin film of Vaseline to the inside neck of traps to prevent escape.
In reference to baits, apple juice frozen concentrate diluted at a 50 – 50 ratio with water is excellent, improving as it ferments. Traps run out of bait in two to three days. (Traps need to be serviced two to three times each week.)
Traps must be strategically placed in high-density wasp locations (10 traps in two specific 15 square foot locations) to intercept pre-existing wasp foraging patterns. For ease of cleaning, traps with captured wasps could be immersed in soapy water and ordinarily disposed of on-site.
A commercial microencapsulated diazinon product mixed with tuna or mackerel has been successfully used as a bait against some western yellowjacket species, but no success has yet been announced on species found in Ohio. Unfortunately, no other insecticide is registered for use as a bait formulation.
It’s primarily German yellowjacket workers found scavenging trash cans and dumpsters, during the summit months, to feed their larvae. Remove trash daily and make certain lids are tight-fitting.
Spraying the inside of garbage containers and dumpsters with propoxur (Baygon), resmethrin, or pyrethrins one to two times each week will provide relief. (Spray near the rim, specifically immediately after the receptacles are emptied.) Residual sprays containing 0.5 percent sugar can be helpful when sprayed on walls or ground surfaces.
Sugar attracts foraging yellowjackets and the residual insecticide eliminates them. Nevertheless, sugar will mold, so be careful in applying such solutions to building surfaces which could discolor when the humidity is high.
There are literally hundreds of products in various formulations labeled for yellowjacket and wasp control. Control of social wasps (yellowjackets), although typically not difficult, has its element of risk in being stung.
It’s best to conduct control operations on nests after dark, about 9 – 30 PM in summer, to avoid being stung, since most of the wasps will have returned to their nest (at dusk or sunset is too soon). If applications must be made during daylight hours, the use of protective equipment, like gloves, hat, bee veil, coveralls, etc., will prevent stings from any airborne wasps.
Below Ground (Outdoors) Yellowjacket Nests
Treat after dark with insecticidal dusts. If using a flashlight, cover the lens with red cellophane paper since light may stimulate yellowjacket wasps to come out of their nests. Dusts should be puffed into the nest immediately followed by a shovelful of moist soil over the entrance hole to prevent escape.
Don’t cover the nest entrance during daylight treatment as returning workers will be all over the immediate area looking for the entrance. Some prefer not to cover the entrance hole either during the day or evening.
Some effective dusts include pyrethrins (Drione), carbaryl (Sevin), or bendiocarb (Ficam). One can also apply propoxur (Baygon) 1.5 percent EC at the rate of eight ounces per gallon of water. Pour into the entrance hole after dark.
Nests Above Ground (Outdoors) Yellowjacket Nests
For control of wasps that build aerial nests near windows, eaves, in trees, etc., insecticides are formulated in pressurized containers that emit a long, narrow stream of spray 15 to 20 feet. Wasp freeze or wasp stopper compounds, containing highly volatile solvents mixed with resmethrin, pyrethrins or some of the newer pyrethroids, produce nearly instant knockdown of wasps hit.
By approaching the nest, spraying in a sweeping motion, the area can be cleared of yellowjackets guarding the nest, followed by directing the spray stream into the entrance hole at the nest bottom to kill those inside.
During the day, this technique doesn’t alarm other wasps returning from the field. No other insecticide needs to be introduced into the nest since all adults present are killed and the immature stages (eggs and larvae) die from lack of care. Typically after one to two days, the nest can be removed carefully.
Yellowjacket Nests in Wall Voids
The German yellowjacket frequently builds nests in the walls of structures. Once finding the entrance, quickly insert the plastic wand of an aerosol generator of resmethrin and release 10 to 30 seconds of material into the void. When possible, inject some Sevin dust into the entrance. (A commercial plastic hand duster or empty liquid detergent bottle filled half full can be used.)
Plug the hole with steel wool and dust the steel wool and surrounding area with Sevin. If done during the daytime, returning workers will chew at the treated steel wool, but within 12 hours all will have been killed.
A veil and protective clothing must be worn when done during daylight hours. Never ever plug an entrance hole without first injecting with some insecticide or wasps may chew through drywall or the ceiling into the home.
Nests located on the second level or higher of a dwelling can occasionally be treated from the inside. Locate the actual nest position by listening with your ear to the wall or using a stethoscope. One may make a small hole (1/8-inch through the drywall with an ice choose or drill) and inject the resmethrin directly into the nest. Some may prefer aerosol formulations of Baygon or dusts of Ficam or Drione.
Sometimes queens could be found overwintering in homes. Fly swatters, pressurized contact sprays or aerosols containing pyrethrins could be used. Usually, spraying indoors is of little or no benefit. Collect individuals with a vacuum device.
Indirect Control of Wasps
Exclude from factories and warehouses by screening window and door openings with mesh of a size not greater than 1/8-inch. Air doors may be helpful on factory doors that are heavily trafficked.
There are many insecticides labeled for control including acephate (Orthene), amorphous silica gel (Drione), bendiocarb (Ficam), bendiocarb + pyrethrins (Ficam Plus), bifenthrin (Biflex), carbaryl (Sevin), chlorpyrifos (Dursban, Empire, Tenure), cyfluthrin (Tempo), cypermethrin (Cynoff, Cyper-Active, Demon, Vikor), deltamethrin (Suspend), diazinon, permethrin (Astro, Dragnet, Flee, Permanone, Prelude Torpedo), propoxur (Baygon), pyrethrins (Kicker, Microcare, Pyrenone, Pyrethrum, Synerol), resmethrin (Vectrin) and tralomethrin (Saga). Certain formulations of bendiocarb, bifenthrin, cyfluthrin, cypermethrin, deltamethrin and tralomethrin are “Restricted Use Pesticides” labeled for licensed pesticide applicators only.
Persons who are in particular sensitive to stings should get a few competitive cost control estimates from reputable, licensed, professional pest control operators who have the experience, equipment and most effective insecticides to get the best job done.