It is important to know that no trap is good at rapid knockdown of yellowjacket populations. For effective use at outdoor events, traps should be placed out two or more days prior to the event. 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. Some apply a thin film of Vaseline to the inside neck of traps to prevent escape.
Traps run out of bait in two to three days.
For ease of cleaning, traps with captured wasps can be immersed in soapy water and usually 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 reported on species found in Ohio. Unfortunately, no other insecticide is registered for use as a bait formulation. It is primarily German yellowjacket workers found scavenging garbage cans and dumpsters, during the peak months, to feed their larvae. Remove garbage daily and make sure lids are tight-fitting.