Stinging insects occur throughout the warm months but generally become more of a pest in the fall. Sometimes these insects cause health concerns before they are noticed and can create liabilities. They can also become a nuisance to employees or customers causing morale and reputation issues.
Often, when they do become a pest, a reactive approach utilizing insecticides becomes a necessity. Sometimes these "reactive" materials create problems themselves. Staining of certain surfaces can occur, they may have an objectionable odor or remain airborne for some time. Some products are phytotoxic. All of these issues could significantly increase the cost of a treatment.
Sometimes a more proactive approach (that uses less pesticide) should be considered. It pays to be proactive to control yellowjackets and hornets. This often can be accomplished by having an effective trapping program for a facility, starting early in the season. An early start will often result in removing the early nest starters — the queens. This alone decreases the number of future nests in your area. Data from 2 years of personal research show that the reduction of fall activity can be up to 70% just by instituting an early trapping program. Continual trapping during late spring into summer will further reduce the number of foraging insects in nests to further stress the population in any given colony. This also reduces the forager population in the fall that correspondingly reduces the number of stings that are received in the fall.
Trapping should start with protein bait in the spring as the queens are usually powering up their ovaries for the summer’s egg laying. Protein baits are used until late June when a switch to sweet baits is appropriate. We found that protein baits caught approximately 65% of the foragers while the sweet bait caught 35%. The numbers being attracted to sweet baits will increase through August and will reach a staggering 85% by the end of August. In studying 10 sites, it was found that numbers of yellowjackets around dumpsters was reduced overall by 88%. Continual trapping further reduced stings to near zero. In those sites where no trapping occurred, painful stings averaged 4 per day.
This program utilizes different types of traps. The traps must be serviced and cleaned on a frequent basis. In addition, the sanitation around dumpster sites and trashcans, when cleaned on a frequent basis, had a significant impact on trap catches. The cleaner the area, the more successful the program.
This is one non-pesticidial treatment to control wasps and control hornets. Another program utilized soap and water for nest removal, generally accomplished in the early to mid spring. Proper safety equipment must be used when doing any treatment to nesting sites.
Whatever program you need, a pest management professional is necessary to survey the area, properly place the traps and service the traps according to the needs of the colonies of that area. A complete understanding of pest biology and behavior is needed. Safety is also important – possibly including working in pairs in case of a stinging incident requiring medical assistance.