Does cleaner contamination ruin cockroach bait? A new study

In addition to the gel bait lifespan study that appears in this issue, Dr. Zach DeVries, an assistant professor in the department of entomology at the University of Kentucky, is helping to shed new light on what happens when common household cleaners and insecticides contaminate cockroach gel baits. Despite their effectiveness, baits are prone to contamination, and it isn’t uncommon to learn that a client applied a household cleaner and insecticide near or even on baits after an application occurred.

Do common household cleaners and insecticides impact the effectiveness of cockroach gel baits? This is exactly what the DeVries Lab wanted to know.

To answer this question, researchers measured what happened when laboratory colonies of German cockroaches (Blattella germanica) were allowed to feed on two commercial cockroach gel baits contaminated with a long list of common household cleaning products and both over-the-counter and professional-grade insecticides.

To test the effects of these contaminants on bait performance, they measured total bait consumption and mortality of the cockroaches. They also exposed the cockroaches to contaminants without a gel bait present to measure mortality from exposure, and again with contaminants applied to plain peanut butter to see whether the ingestion of contaminants in the absence of gel baits could drive mortality.

Surprisingly, most of the contaminants had no significant effect on bait efficacy overall, with most baits exceeding 90 percent mortality within seven days.

These results were informative and not what I expected. But a key takeaway for me from this study is not that contaminated baits are still effective. Instead, don’t be quick to blame bait contamination as the reason a treatment fails the next time you encounter a persistent infestation. Interview the client to determine whether resistance or bait avoidance might be in play.

Read more about this study online at https://pubmed.ncbi.nlm.nih.gov/40676718/