Gel Bait Passes Field Test At Famed Lincoln Park Zoo

"Mommy, Mommy look at those cockroaches!" could be the startled reaction of a child encountering roaches in one of our nation’s zoos. Later, when asked about her trip to the zoo, this child may unfortunately recall only those roaches and not much else. Fortunately, incidences like this will be declining as control techniques improve and as improved pest control bait products are incorporated into pest control programs.

In zoos, cockroach control is often performed under some of the most adverse conditions possible. Zoo structures provide plenty of harborage sites for pests and often have high humidity and temperatures. These conditions are maintained at constant, high levels year-round, providing perfect conditions for cockroach growth and development. Cage interiors and many walkways are typically washed daily. Since food and water are abundant, any bait for the control of pests must overcome extreme competition to achieve control.

All these conditions were present in the Great Ape House (GAH) of Chicago’s Lincoln Park Zoo - with one additional challenge, an extremely high German cockroach population. The GAH, therefore provided an ideal situation for evaluating the limits to which a new cockroach control bait or any other formulation could perform.

The ability of Maxforce Roach Control Gel to reduce a large long-lasting German cockroach infestation under the extremely adverse conditions present in the GAH was outstanding. The German cockroach populations, in treated areas of the facility, were reduced by more than 96 percent in only seven days. During the 91-day (three-month) duration of this study, the level of cockroach reduction was never less than 94 percent. Amazing as it may sound, this all happened with only a single bait application. This product showed rapid control, a high level of effectiveness and durability under the most adverse environmental conditions.

An effective alternative. Currently available products had been ineffective in reducing the large, long-standing German cockroach infestation in the GH to an acceptable level. Zoo management was looking for a safe and effective solution to their problem. Beginning April 6, 1989, zoo management agreed to provide the research site for Dr. Theodore Granovsky, R.P.E.., and Kevin D. Haack of Granovsky Associates, Inc. to evaluate the new Maxforce Roach Control Gel in the GAH for the control of German cockroaches.

They worked with Gene Brimer, pest control coordinator at the Chicago Lincoln Park Zoo. Brimer has 20 years of experience with various pest control firms in Chicago and Milwaukee, plus two years of experience with the zoo. He was on-site during all of the bait applications and post-treatment monitoring.

In the past, the zoo had used exclusion and some baiting efforts to decrease the GAH German cockroach infestation. According to Brimer, these pest management efforts had caused a visible reduction in roach populations. Nonetheless, cockroach populations were still very high at the beginning of this study.

Ape house environment. The extreme environmental conditions existing in the GAH provided a unique opportunity to determine the performance limits of the new bait product: The climate in the GAH is tropical with temperature and humidity maintained at constant high levels year-round. In addition, food for the more than 20 apes is placed on the cage floors each day. Scraps of uneaten food and ape feces are two major sources of food for roaches.

There are also a number of birds which are housed in the GAH. Feeders containing birdseed are provided for the birds. Spilled birdseed and bird feces are two additional food sources for pests. Water is readily available. Every cage has at least one source of running water. The water runs continuously to provide the apes and birds with a constant source of fresh water.

The main cages, nursery, isolation cages and internal walkways are washed at least daily with high pressure hoses - sometimes two or more times a day. This practice creates conditions conducive to cockroach development and inactivates pesticide applications. Despite these frequent washings, cockroaches are probably not without food for long.

Bait application. The gel bait was applied the day following the pretreatment survey. Hundreds of bait placements were made with syringe-type applicators provided by American Cyanamid. The among of bait placed ranged from drops measuring 1/8-inch to a ribbon of bait ½ inch long.

Care was taken to make bait placements out of the apes’ reach. No bait was applied in the kitchen nor inside the cages, and no exposed surfaces were treated. Bait was placed directly into knotted rope ends and cracks at cage edges; around air-duct work, electrical conduit and pipes; into cavities formed by honey-comb concrete; and into other cracks and crevices.

Application of he roach control gel was focused in areas where initial surveys indicated roach populations to be most numerous. The largest cockroach population was seen, and thus the heaviest bait applications were made, on the third floor. All cage areas exposed to the third floor walkway were treated, with the exception of one cage which was left untreated as a check.

A single application of the gel was made on April 7, 1989, and no follow-up gel applications or other treatments were used during the 91-day test. A total of 26 ounces of bait was applied in the entire 2,500 square foot facility. It took a total of 18 staff hours to complete the job, a bit labor intensive but worth the effort when you consider the benefits; the excellent results obtained, the product safety and the elimination of a pest capable of carrying medically important disease organisms to expensive and rare pets.