The Better the Palatability, the Better the Acceptance

 

But to improve bait palatability, PMPs must think like a cockroach. 

 

“Thinking like a cockroach, I think a high moisture content of the bait is a quality that makes it more palatable, because as the bait placements age and dry out, acceptance dramatically goes down,” said Foster.

 

Since water is a limiting resource for cockroaches, it serves as a universal attractant in gel baits. In fact, according to the Mallis Handbook of Pest Control, cockroaches consume more gel bait than solid formulations that contain less water, even when both formulas had similar concentrations of the active ingredient.

 

Because of the role moisture plays in palatability, Foster recommends scraping and replacing bait placements monthly, when they not only become unacceptable for the cockroach, but they also become unsightly.

 

Cat Heisler, general manager for Pete’s Pest Control, agrees. She recommends checking the label instructions for how long the bait is intended to stay moist, then tinkering with the replacement frequency based on field experience with the site.

 

“The palatability of bait is seriously limited once it dries out,” she said. “A gel bait that retains moisture longer retains its palatability.”

 

With other competing food sources available, retaining that palatability is essential. According to Heisler, reducing additional food sources through proper food storage and sanitation efforts can improve the acceptance of gel baits, but they still need to be attractive to be effective. 

 

“Food-grade attractants that mask the active insecticide really help,” she said. “Unfortunately, since the tasty ingredients are not active ingredients, they are not detailed on most labels.”

She recommends that PMPs pose questions about these ingredients to their suppliers and manufacturer representatives.

 

“There really is a lot to learn from these folks that is not included in labeling,” she said. “I like to have my manufacturer representatives bring samples and provide on-site demonstrations of how best to use their products.”

 

Even with food-grade attractants observation is necessary before determining the optimal flavor.

 

“Are the cockroaches more interested in sugar and carbohydrates or fats and protein?” Heisler asked. “A little experimentation and observation will provide the answer as to which baits will be more effective.”

 

Foster likes to call his method of testing the buffet. He uses multiple gel baits in tandem to test which are most appetizing to the current population, and to see if bait averse cockroaches have been introduced.

 

It is also important to take into account what the cockroaches were feeding on before control measures began.

 

“Observe what the cockroaches are consuming. Use gels that mimic that diet. Sometimes cockroaches will go for a bait that contains an ingredient missing from their diet,” Heisler said. 

 

“Trial and error can be useful initially. Using different baits with a monitoring system provides excellent information on what will be effective in follow-up visits.”

 

For cockroach species  like the German cockroach, which reproduce rapidly and reach adulthood in just four to six months, in-depth testing isn’t necessary because just about any bait will do. 

 

“Larger species are more selective, often taste-testing available baits before consuming enough for a kill,” said Heisler.

 

So what is the balance between palatability and the amount of active ingredient? 

 

“I think about cough syrup and my grandkids. It sure is easier getting the tasty stuff down their throats,” she said. “Active ingredients in gel baits are usually bitter or sour. To be effective, gel baits must be tasty enough to mask the active ingredient and attract the cockroaches, yet must be potent enough to eliminate the cockroaches. Too weak of an active ingredient can lead to chemical resistance.”