Questions & Answers

A. Snap traps, snap traps, snap traps! Lots of them. I have had terrific success using snap traps to control roof rats.

Baits that I have found work well include salami, cantaloupe and sardines. The roof rat population in your area may prefer other baits, but I would recommend giving these a chance before switching to some other materials.

In addition to snap traps, I have found the use of liquid bait also very effective against roof rats. In my experience, I believe I have seen more juvenile roof rats succumb to liquid baits than adults. This may be an artifact, but I often find far more juveniles dead or dying as a result of toxicant ingestion than adults.

Both apple juice and pineapple juice cut in half with water have worked very well as the base for liquid baits. You should expect that this material will only remain attractive for 48 hours or less during the warmer months of the year. If the environment you are using it in is dusty, the useful life of this liquid bait in open trays will be only one evening. I would not attempt to place liquid bait in larger stations and leave it unserviced for a week or more. In my experience, these baits go rancid very quickly.

INSECTICIDE PAINTS ARE USUALLY A BAD IDEA

Q.Some of our customers have been asking whether any of these paints that contain insecticides might be useful in their accounts. We know little about these materials, and are wondering whether we should recommend them to our customers. Do you have an opinion on insecticide-based paints? (R.W.)

A.Paints containing insecticides (usually an organophosphate) have been available for 10 years or more. The names have changed often, and I have found it difficult to obtain information that shows that these materials do what they claim in their ads. Research results from qualified researchers with regard to the efficacy and safety of these materials is essentially nonexistent. I would be very skeptical about recommending these materials in any of your customers' buildings.

With the concern about cockroach resistance, it seems strange that anyone would want to apply an organophosphate over broad surface areas at low dosages, thereby exposing the entire population to a deteriorating dose over a long period of time. This would seem to do nothing more than enhance the level of resistance in the exposed cockroach population. Also, why anyone in this day and time would consider applications of insecticides to broad expanses in rooms where the treated surface might be contacted by adults, children and pets is beyond me. I believe that the science of structural pest control has moved well beyond this type of product.

Jeffrey Tucker is a contributing editor to PCT magazine. Questions may be addressed to him at Entomology Associates, P.O. Box 70375, Houston TX 77270, or faxed to 713/681-9069.