Baits Don't Always Work

Q: We’ve been baiting a particular restaurant with several different baits for about five months. We still have German cockroaches being reported by our customer, and when we go to the account we usually find evidence of infestation. Baits work very well in most accounts, however, in this large, old restaurant, we are not getting control. Are there any problems with bait resistance or are we simply expecting too much out of these materials? (J.C.)

A: I have encountered this problem myself on several occasions. The current crop of cockroach baits available to the structural PCO has never been better. There are several very effective active ingredients available in a number of formulations. Unfortunately, bait application cannot always get to the source of some cockroach infestations. This is particularly true in old buildings. It seems as if roaches just continue to pour out of the structure. Baits in stations or gel formulations are not capable of penetrating back into some areas. There are limitations on how we apply many of these formulations, and cockroaches simply do not come in contact with the bait materials at a large enough rate to eliminate the population.

Another factor that can affect the efficacy of baits is the level of sanitation in these restaurants and kitchens. If it is low, then cockroaches have abundant food sources and they may not be feeding on your baits at a rate sufficient to control the population. While this doesn’t happen often, it does occur and other steps should be taken to eliminate the infestation before switching to baits. For example, you may want to use a traditional pest elim-ination approach using directed contact applications of 1% to 3% dual-synergized pyrethrin applied with an applicator designed to inject these materials deeply into cracks, crevices and voids. A micro-injector or an Actisol unit can perform this task. This approach will require more labor and effort but has been proven for many years to be extremely effective in eliminating deep-seated German cockroach infestations. Follow-up treatments with crack and crevice residual applications are also necessary with this approach and have a long history of effectiveness. Once the population has been eliminated, particularly in the more inaccessible or deep areas, then baits can be used very effectively to maintain acceptable levels of control.

I know this answer may sound as if I am promoting old technology, particularly in light of the industry’s infatuation with baits. However, I’m simply trying to remind you that integrated pest management is just that: an integration of all available tools and techniques, including some that may have been around for a while but have proven themselves effective, nonetheless. Remember, the goal is to eliminate the pest problem in the most efficient and safe manner possible. Don’t let the age of the technique get in the way of sound decision making.

Jeffrey Tucker is a consulting entomologist who is president of Entomology Associates in Houston, Texas. To contact Tucker, call 713/681-9069. Questions can be sent to Q&A, c/o Entomology Associates, P.O. Box 70375, Houston TX 77270, or faxed to 713/681-9069.