Baits for cockroaches and ants have been around for years. But pest control professionals, as well as the research community, still have a lot to learn about what makes bait products more effective in some situations, and less so in others.
But early this fall, a group of researchers, PCOs, consultants, and manufacturers’ representatives met to discuss just that, and come up with initiatives for future research. The event, which took place at Purdue University, West Lafayette, Ind., was sponsored by the university’s Industrial Affiliates program. The members of this group include Zeneca Professional Products, DowElanco (soon to be Dow AgroSciences), and S.C. Johnson & Son, along with its subsidiary Whitmire Micro-Gen Research Laboratories. Established in 1991, the Industrial Affiliates Program serves to assist the urban pest management community in meeting research and education needs for the coming years. The program, called “The Science of Baiting Urban Pests,” was the second workshop sponsored by the Industrial Affiliates.
Attendees of the one-and-a-half-day workshop were able to learn about the latest research findings as well as contribute their own observations. The event was likely one of the first informal meetings that brought together this varied group of individuals to talk about baiting issues. Current issues and future directions in the areas of ant and German cockroach baiting were the highlighted topics for the program. The goal of the workshop, said Daniel Suiter, a research director at Purdue and the director of the Industrial Affiliates program, was to provide urban entomologists the opportunity to exchange ideas as well as to focus their attention on issues influencing the research agenda on ant and German cockroach baiting.
“Baiting is such a hot topic these days with the IPM-related thrust in the industry that it was kind of a logical thing to do,” said Suiter. “Customers, homeown-ers and operators want less toxic methods of pest control. Baits fit that glove perfectly, so we tried to merge the need for that with a meeting.”
The Industrial Affiliates committee is hopeful the workshops will become an annual program. The first program, covering the issue of insecticide resistance, was held in 1991.
The ultimate objective of the baiting workshop was to develop a list of research initiatives in each area that would lead to improved bait products and technologies for the urban pest control industry. Invitees were also encouraged to submit, in poster format, any scientific research projects they’d completed or other findings in the field.
THE WORKSHOP. The workshop was kicked off by a presentation from Victor Lechtenberg, Dean of the School of Agriculture. Then, to bring attendees up to speed on the state of ant and German cockroach baiting, four highlighted speakers discussed their research findings, beliefs and need-to-know “wish lists.” University researchers Don Reierson and John Klotz of the University of California, and Art Appel and David Oi of Auburn University were the highlighted speakers (specific findings on page 32). Then attendees broke out into one of two discussion “think-tank” sessions: one focusing on German cockroach baiting, the other on ant baiting. Both groups were charged with brainstorming and then prioritizing to arrive at a list of important research initiatives to be studied in the coming years. On the second day of the program, the groups compiled their thoughts and reassembled to present their recommendations.
“We got a lot of good feedback from a lot of the attendees,” said Suiter. “People thought it was a great success and want to participate again.” Suiter was also pleased with the contributions made by PCOs, from whom academic researchers rarely get the opportunity to draw feedback from the field.
Interestingly, the research findings found to be of most interest to conference attendees were quite similar for the topics of baiting both German cockroaches and ants. The groups both pointed out they would like to see more research conducted in the areas of what makes a bait product effective, and what biological factors may also have an impact on a bait’s attractiveness.
ANT RESEARCH INITIATIVES. Participants in the ant baiting workshop discussion first identified the major ant species for which more research is needed, then prioritized their three top research ideas. These were followed by three additional secondary initiatives.
The ant species identified as the most troublesome across the country, and thus the species most in need of further research, were, in order of importance, carpenter ants, crazy ants, Argentine ants, pavement ants, and odorous house ants. The fire ant, although also a very economically important pest, is already being researched somewhat heavily, the attendees said, with federal funding having been allocated to improving control methods.
“They’re very economically important,” said John Klotz of the ant species named. “They’re what pest control operators are confronting out there, and yet they don’t have good baits for these ants.”
The three most pressing research initiatives, attendees said were, in order of importance, to learn more about food preferences among specific ants, about the most effective bait delivery systems, and about what causes bait avoidance or rejection. Other initiatives, although not as pressing or important, should focus on pheromones, sampling techniques, and food distribution among ant colonies. Attendees felt the researchers should further learn how to isolate pheromones, estimate colony sizes, and find out how far baits spread within colonies.
Understanding food preferences could involve getting PCOs across the country to participate in nationwide studies that employ standardized diets and optimized, consistent baiting schedules, the attendees said. A study of bait delivery systems would look at physical characteristics of bait stations, including such factors as size, shape and color, in addition to how the bait performs in different environments. This study would also analyze the effectiveness of different types of baits, such as scatter, gel and paste formulations.
The topic of bait avoidance and rejection would best be studied by analyzing such things as ants’ learning behaviors, seasonal factors, particle size, and weatherability. In addition, researchers should look at both the matrix and the active ingredient to determine if either or both are contributing to bait avoidance.
COCKROACH RESEARCH INITIATIVES. The top cockroach research ideas were similar to those chosen for ants. First, attendees said, researchers should aim to learn the various factors that affect bait performance. These include such things as why populations plateau, but aren’t eliminated, with the use of baits; aging of baits, bait ingredients and competing foods’ effect on baits. Many of these areas have already been studied, but more detail about these factors would possibly help prioritize some factors over others. Many of the factors that could affect bait performance have also been theorized and talked about, but there has been little research to back the theories up, attendees said. “The whole focus was how do we enhance baits to make them more attractive to cockroaches and stimulate feeding on the baits,” said Dr. Richard Kramer, a PCT columnist and also a moderator for the cockroach baiting discussion. “It just isn’t known how well baits compete with competitive food sources.”
The next most important area for further study was nutritional ecology: learning about cockroaches’ feeding patterns, population development, and behavior and physiology. Another important topic was said to be the physiology of attraction: learning about such things as distance attraction, learned behaviors, repellency and bait placement.
Other issues for further study (which were not rated as highly) include evaluating monitoring techniques, looking at the use of baits with other control approaches, such as IGRs and residuals, and analyzing spatial relationships. The attendees also noted they’d like to see research conducted on bait station design and educational programs for technicians, customers, regulatory personnel and researchers about such things as how best to apply baits and safety considerations.
Overall, Suiter was pleased to find that both workshops were interested in the area of nutritional ecology — the study of what insects eat and why they eat it — an area that research at Purdue specializes in. “The whole research program has to do with foraging ecology and nutritional ecology in cockroaches, ants and termites so we really have a slant towards baits here,” said Suiter. “[The sessions] confirmed our belief that more work has to be done on the nutritional ecology of cockroaches and ants.”
Now that the recommendations have been made, it’s up to the attendees and planners of the program to disseminate the information around the United States, so that perhaps some of the research initiatives can be discussed and set into motion. Currently, Suiter is compiling a packet of information from the meeting which will be distributed to all attendees and researchers that were unable to attend. “If we’re going to get anything accomplished, more people have to know about it,” said Suiter. “Certainly there’s enough work there for years and years.”
Another future consideration is funding, he added, and perhaps finding federal funds that will help make some of the research initiatives become reality.
“The important point is really the follow-up,” said Suiter, “to make people aware this is what the industry, the manufacturers and the research community considered important in ant and cockroach baiting for the next five to 10 years.”
The author is managing editor of PCT. Dan Suiter of Purdue University and Dale Kaukeinen of Zeneca Professional Products contributed to this story.
Sidebar: NEW RESEARCH FINDINGS ON ANT AND COCKROACH BAITING
The four highlighted speakers at the Purdue program shared a few of their, and their colleagues’, recent research findings. Below, just a few of the specific findings from each institution.
Don Reierson, University of California-Riverside
- Roaches spend less than a minute at a water source and less than 20 minutes at a food source. They eat about 2 mg of food per day.
- Single-feed baits may be more effective than multiple-feed baits, although there may be less chance for a secondary kill if the toxins work too quickly.
- Researchers have seen a decelerating level of control with cockroach baits over time. Some baits are not performing as well as they did two to three years ago.
- Cockroaches learn quicky and may learn to avoid a bait after feeding on a sub-lethal dose.
Art Appel, Auburn University
- Water-laden baits, such as gels and pastes, may dry out over time and harden. Applying a smear of gel or paste bait, instead of a glob, may be more effective. The glob may dry out and become too hard for the cockroach to feed upon. The smear, on the other hand, will crack as it dries, providing more edges upon which cockroaches can feed.
- Food and water deprivation are critical. In the lab setting, if roaches are denied water for 72 hours, they will more readily eat baits.
- In lab experiments, cockroaches were more likely to feed on baits when also given harborage. Providing less or no harborage places “stress” on the cockroach in the lab setting and it does not readily feed upon the bait.
David Oi, Auburn University
- When it comes to ant nutrition, queens and larvae need proteins for egg development, foragers need carbohydrates for energy, and workers and larvae need lipids for energy and food storage.
- Liquid ant baits tend to limit toxicant to workers. Solids get carried back to the nest and so more larvae are affected.
- Starvation of ants allows greater food consumption and encourages more foraging, which in turn leads to faster food distribution within the colony.
- Many factors affect bait preferences. These include food changes, environmental changes and colony cycles.
John Klotz, University of California-Riverside
- Pheromones have terrific potential for use in baits. And although the pheromones of some ant species are very short-lived, it is likely that pheromones can be packaged and formulated to increase their longevity.
- Redirecting ants can be a part of a successful control program. Placing baits in ants’ trailways will help to draw ants away from the structure and to the baits.
- Because ants utilize a recruitment system to bring other colony members to known food resources, it is likely more effective to clump granular baits instead of scattering them randomly. In this way, ants will recruit to the baits in greater numbers, and the baits will compete favorably with other natural food resources.