On Your Toes

Bees, yellow jackets and wasps — oh my! These stinging insects can create fear and panic in the most experienced PCO. They attack when least expected and leave painful reminders of what one can expect when confronted with them. I have always held these insects with the highest respect and have learned to inspect from afar any of their potential hiding places before I approach the threshold of an alarm response. From studying their behavior, I have developed and fine tuned techniques for proper control without being stung. Species exhibit behavioral differences that should be taken into account when planning. Reported herein are biological issues, hypothetical situations and possible control techniques — some unorthodox — that any PCO can use.

THE CASE OF THE NEST BUILDERS. Small nest builders are always the easiest to control, yet they are cryptic and can be difficult to locate. They often nest on the underside of vegetative material and are usually less aggressive — at the beginning stages of nest construction, the breeding female is more willing to abscond because of little energy input forwarded into nest construction; hence, "let’s take off and build somewhere else." Furthermore, species that build smaller nests have more to lose when confronted by an enemy.

Many times it is the breeding female (in some cases more than one) that defends the nest. Therefore, the likelihood of an attack is slim — seriously! Many times, the breeding female will charge, a term called "pseudo attack." It is scary but never results in a sting — it is wasp language saying, "Get lost!" However, there is always the possibility of an attack.

Locating nests can be tricky. A long broom handle (there are several that are extendable) is invaluable for this task. Lightly disturb a potential nesting site in vegetative material in order to elicit a slight alarm response. Take your time so you don’t miss any potential breeding sites and alarm responses. Once a breeding site is found, follow the insect because they usually fly for about 10 to 15 seconds and then return to the nest. The nest can be controlled with a quick spray from an aerosol containing pyrethroids. Spraying the nest during the day is acceptable — any residual will kill remaining foraging workers. Remember — it is the breeding female(s) the PCO wants. Eliminate her and the problem is solved.

THE GROUND NESTERS. What is worse than a rabid cocker spaniel chasing after you? How about several yellow jackets chasing you a considerable distance! Ground-nesting wasps can be elusive. Most people are stung because they inadvertently disturbed the nest. Nests are hidden quite well and workers only come out in full force when disturbed.

So how does one find a potential nest? Yellow jackets are voracious predators. Thus, the best way to track an individual worker is to place bait in areas where activity has been sighted most frequently. This is where patience is needed. Use tuna in oil. It could take five, 10 or 30 minutes, or even longer until the bait is located. Let the foraging worker take some meat. After a good grab, they will head directly back to the nest. Yellow jackets fly slower when carrying food, yet one still needs to be quick when following a worker. Mark the nest location with a wooden stake. Treating the nest with dust is an excellent method. Spray directly into the nest using a bulb sprayer, or better yet, place spoonfuls directly into the entrance. Placing spoonfuls causes less disturbance, lowers chemical cost, and the technician can properly document the amount used.

Conventional wisdom states that one should treat at night when the majority of workers are nesting and are less active. From my experience, I feel a day-time application of dusts is perfectly acceptable. However, alarm responses will be greatest during the day and you will probably have several workers defending the nest. Thus, protective clothing is imperative.

After a day-time application, visit the site 24 hours later to determine the level of control. Another method would be to flood the nest entrance with a synthetic pyrethroid. One can premix the proper amount of finished product in 5-gallon pails. This is a good method if the nest site cannot be reached with a hose. Flushing the nest entrance with one 5-gallon pail should do the trick. Breeding females remain in the nest continuously, and the possibility of direct contact is good. After application, allow 24 hours until you check up on the situation. Repeat if necessary.

CARPENTER BEES. One can show off his/her prowess when controlling carpenter bees. It can be time consuming depending on the number of holes requiring treatment. However, if the treatment is conducted correctly, re-treatment will not be necessary. Carpenter bees are not social insects and do not live in nests or colonies. The adults overwinter, typically in abandoned nest tunnels (proper treatment can prevent this from happening). In the spring, the survivors emerge and feed on nectar.

When attacking wood, the female typically bores a circular hole (the same diameter as her body) straight into the wood across the wood grain for a distance equal to her body length. Then the gallery takes a right-angle turn, usually with the grain of the wood. New galleries average 4 to 6 inches (10 to 15 cm) long, but galleries developed/used by several bees may extend up to 10 feet (3 m). Starting at the closed end of a gallery, the female provisions each gallery cell with a mass of pollen and regurgitated nectar upon which she lays a single egg. This portion of the gallery is then sealed off with a chewed wood-pulp plug, making a chamber or cell. This process is repeated until a linear series of five to six cells is completed, about one cell per day.

Treatment of cell lines can be conducted by using an aerosol containing a pyrethroid, or applying dusts or foam. Personally, I prefer the latter. With new formulations and chemistries, foam with a good residual insecticide should be more efficacious. Simply treat each hole then plug them afterwards with calk.

THE SENSITIVE ISSUE: HONEY BEES. Consider yourself lucky to witness a honeybee swarm — it is a remarkable thing. I tried to explain this to a friend of mine who had a colony swarm and nest in a tree that was on the property site he was managing. After I explained the beauty of a swarm, I asked what he wanted to do. It is easy to locate and kill honeybees. Their nests are conspicuous, especially when they nest in tree vegetation, and direct application of a synthetic pyrethroid or dust is straightforward. However, people are usually sensitive about hurting honeybees — they are sometimes considered a tolerated pest. My friend’s response was simple and predictable: "I want to get rid of them but I don’t want to kill them." Classic.

The problem was that the location was in California and one must assume that any potential honeybee colony there is Africanized. In fact, one needs to assume any honeybee colony from Texas to the West Coast is Africanized. This is where the "tolerated pest" status becomes void. In this situation, I advised marking off the area first, and if necessary, educating the tenants of the potential problem. My friend mentioned that all these preliminary steps had been taken — so now it boiled down to the control method. He was still hopeful that this was not an Africanized strain, and luckily it was not. He did not want to kill the colony so the only option was severe agitation of the colony with water.

I advised the following: 1. Rent a pressurized water sprayer; 2. Spray the colony with water every day three times a day; and 3. Be patient. I assured him they would move. Well what do you know, they did! Honeybees eventually look for new nesting sites when disturbed continuously. After three days the colony absconded to a new location, and not one drop of chemical had been used. Happy hunting!

The author is a regional technical director with HomeTeam Pest Defense. He earned his Ph.D. at the University of Georgia and can be reached at ripser@giemedia.com.