Cockroach Baiting Guide

Here are some new tips to help pest management professionals control these pests using both gel and granular baits.

Okay, here’s the big question: "What happened to all the cockroaches?" It’s not as if all the cockroaches have disappeared — there’s still plenty of them to go around. Pest management professionals, however, have stopped complaining, in large degree, about cockroach problems and control failures. Remember six to seven years ago when fears of German cockroach resistance and strategies such as "product rotation" were all the rage? What happened to those days? Why are we talking today more about ants than German cockroaches?

The answer to this last question lies in the vastly improved technologies in baiting products introduced over the past six to eight years. For nearly a decade, professionals relied on Maxforce stations as the bait of choice for German cockroaches. Due to the expense in producing stations, they were not widely used as the primary strategy for German cockroach infestations. Some used the Blue Diamond paste bait but many balked at the inconvenience of application using a knife or spatula. Blue Diamond was the first crack and crevice bait aimed at German cockroaches.

Then along came Avert Dry Flowable bait that permitted convenient direct application into cracks and voids where cockroaches lived. Maxforce Gel quickly followed and managed to acquire food-handling status first. Other crack and crevice baits joined the fray, including Avert Gel bait, Siege Gel, Drax Cockroach Gel and more recently, Pre-Empt.

MAKING GOOD DECISIONS. Since such baits have been in use, German cockroach infestations have become less of an issue in the minds of most service professionals. Why? First and foremost, crack and crevice baits force the professional to place the baits where cockroach control products will do the most good — cracks and voids. After all, where cockroaches live are the source(s) of the problem.

Second, moisture — or at least moist foods — seems to be an irresistible need for German cockroaches. Blue Diamond demonstrated this when the company showed a video of cockroaches venturing out within seconds to feed on its bait. Many professionals relate the same story regarding practically all of the gel baits. Some service professionals have even equated the effectiveness of the bait by how fast the cockroaches respond once the bait is applied. This thinking is flawed as many variables may affect a cockroach’s feeding preferences and response to any bait.

The primary factor in bait feeding response lies more in the fact the bait is placed close to the harborage. A number of studies have demonstrated a German cockroach’s preference to remain as close to "home" as possible. Why would cockroaches take the risk of a long trip when suitable food is nearby?

It has always amazed me how much subjectivity goes into one professional’s personal preference of any pest control product over another. Professionals develop their preferences and will swear by certain products, insisting a competitive product does not work. Both laboratory and field studies demonstrate each bait product’s efficacy — they all kill German cockroaches. Different professionals have success with every bait product. Likewise, professionals have their failures to control some infestations with the same products. Effectiveness of a cockroach bait lies more in where it is placed, how it is placed and how much is placed. Whether the infestation is eliminated is the true measure of effectiveness.

HELPFUL HINTS. How should cockroach baits be applied to achieve the best results against German cockroaches? Here are some tips to follow:

1. Nothing — no bait, no liquid, no fancy equipment — can replace an efficient and thorough inspection. Baits can only work if ALL the cockroaches find and feed on the bait (of course, if bait is the only strategy being employed). True, secondary kill does occur through early instar nymphs feeding on contaminated feces of older cockroaches who have fed on the bait. But you must find the harborages in order to know where to place the bait.

2. Inject gel and powder baits into cracks and voids where cockroach activity is present or is indicated (e.g., fecal smears). Food placed right on the dinner table is hard for cockroaches to resist. DO NOT apply gel and powder baits onto exposed surfaces or in corners. These baits are designed and labeled as crack and crevice products.

3. It is best to apply small placements of bait in numerous locations as opposed to larger amounts in fewer sites.

4. Be aware that it is often easy to apply too little bait where larger cockroach populations are encountered. In such situations, a follow-up visit one week later is a great idea to apply more bait where needed.

5. Although research has shown that application of baits into areas where other insecticide formulations have been applied is not as great a problem as once feared, it is still better to apply baits alone.

6. In situations where cockroaches are present but bait cannot be applied into harborage, how close can the bait be applied in other cracks in relation to these active harborages?

For example, about nine years ago, I had the opportunity to field test Avert Dry Flowable Bait in a heavily infested home. Dozens of German cockroaches were residing in a corner-round at the ceiling level. The cracks were too wide to permit application of the bait, so the bait was applied instead to cracks in a doorframe and around cabinets more than 4 feet away. Interestingly enough, when the follow-up visit was made a week later, even the cockroaches living in the untreated cracks had been controlled. Total elimination was achieved in two weeks.

7. Similar to #4 previously, create your own "cracks" to apply baits where no cracks exist.

For example, in a school kitchen once, cockroaches were harboring in walls and behind the splashguard of a sink. No suitable cracks existed for the application of gel bait. A piece of cardboard, folded upon itself served as a "crack" in which to apply bait. The cardboard was then lodged between the water line and the wall. German cockroaches have a preference for harboring in cardboard so once they entered, they fed on the bait. This trick succeeded in this situation and in numerous others since.

8. Vacuum as many cockroaches as possible prior to baiting. Fewer cockroaches ultimately require less bait to achieve results. Plus, you walk out of the building with a large percentage of the infestation already controlled.

9. Store baits appropriately — out of extreme heat or cold and away from other insecticides. Baits can become easily contaminated by insecticide odors, leading to less satisfactory results.

10. In situations where a gel or powder bait cannot be applied (e.g., around electronic equipment, fish tanks, etc.), bait stations may be used. Be sure to attach these along edges or in corners — as close to active harborages as possible. Cockroaches like to follow structural guidelines, such as edges and corners.

11. Gel cockroach baits can be used in some situations for larger cockroach species, but these cockroaches may consume far more bait than is necessary to kill them. For this reason, using gel baits is more expensive for larger species than granular baits, discussed later in this article.

One situation where gel baits would be suitable, however, is in baiting cockroaches in manholes. If ¼-inch hardware cloth is folded over itself a couple times, it creates enough surface area to which gel cockroach bait can adhere and still permit American and similar cockroaches to feed. Gel bait is smeared evenly over the wire and the "bait station" is then hung along the inside of the manhole where cockroaches can access it. Bear in mind that considerable bait may be necessary for large populations so be prepared for the added expense.

12. Replace bait stations at least every three months, otherwise they may become cockroach "hotels." Some professionals, however, leave used bait stations — covered with fecal smears — in place and rotate new stations next to the original station. The thinking is the one with fecal smears helps lure cockroaches to the fresh bait. No research has been completed that proves this fact — the proper location of the bait station may be a more important factor in the success of this technique.

GRANULAR COCKROACH BAITS. A number of granular insect baits are targeted at cockroaches, in particular larger cockroach species. Products include Baygon 2% Bait, Niban G, Niban FG, LarvaLur and Maxforce Granular Insect Bait. American, Oriental, smokybrown and similar cockroach species all respond well to most bait products. Gel cockroach baits are also readily consumed by these species; however, as mentioned previously, the cost using of gel baits against larger cockroaches may be prohibitive.

As with gel baits for German cockroaches, proper placement of granular baits is key to success. Larger species will travel farther than German cockroaches in search of food, but like their cousins, larger cockroaches only like to crawl as far as they need to acquire a meal.

More than ten years ago, Dr. Rick Brenner of USDA demonstrated that cockroach baits are more effective in controlling smokybrown cockroaches than traditional treatments. He tested baits in homes in Gainesville, Fla., that had been serviced unsuccessfully by a number of companies. By determining where the cockroaches were harboring and placing baits in those areas, the infestations were solved.

SUMMARY. Cockroach baiting, like any pest control technique, gets easier with experience. Remember to inspect thoroughly to determine where your baiting efforts will produce the best results. Follow-up where necessary to ensure the baits are accepted and whether more bait is needed.

The author is manager of technical services, Terminix International, Memphis, Tenn. He can be reached at shedges@pctonline.com.