Updates In Securing Exterior Rodenticide Baits

During the past several years, the industry has increased the practice of securing rodenticide baits in exterior tamper-resistant stations around commercial accounts. But this low-hazard baiting strategy is beginning to take on more variations, and as a result, new questions are emerging.

For example: “Is it an FDA, USDA, or EPA regulation that baits be secured in exterior bait stations? Does it make a difference whether baits are secured in a horizontal or a vertical format? Is it acceptable to secure packet style baits?”

First, there is no regulation that requires you to secure baits in exterior bait stations. Many progressive pest management companies have embraced the practice of securing baits in their efforts toward providing greater baiting effectiveness while at the same time reducing the potential baiting hazards associated with exterior baiting programs. Thus, the industry in fact has exceeded the standards as set by regulatory agencies. Food plant inspection services such as the American Institute of Baking (AIB) do not penalize for unsecured baits, but they do recommend this practice to their clients because it reduces rodenticide contamination risks.

CONSIDER THE ADVANTAGES. For those professionals “sitting on the fence,” securing baits provides several advantages and direct benefits to your exterior baiting program: Secured baits cannot be shaken out of the station by people or wildlife. Furthermore, rodents cannot move or kick secured baits into the entryways of the station, rendering them more accessible to the reaching hands of people, the paws of non-target mammals or the beaks of birds.

Rodents (rats, mice squirrels, chipmunks, ground squirrels, etc.) characteristically “cache their food.” Rats and mice do steal our rodenticide blocks and packets out of stations in their attempts to “squirrel the baits away” back in their burrows or to other areas. This is called bait translocation. Throughout many years of inspecting thousands of bait stations, I have discovered it is not uncommon to find up to 10% of unsecured baits in bait stations around commercial accounts lying on the ground outside the station. I also commonly find some bait stations totally empty. The most optimistic assumption is that rodents have consumed the bait within the stations, or that they have successfully taken the baits back to their burrows for later consumption (which may or may not be the case). By securing the baits within the stations, the chance of bait translocation is dramatically reduced.

Secured baits provide the needed additional bait protection in ultra-sensitive accounts such as zoos and wildlife parks. Zoological parks have lost expensive animals over the years because of rodenticide poisoning. In addition, elevated secured blocks last longer and stay fresher. Rodenticide bait blocks and pellets contain food quality grains. Certainly, these are also attractive to many insects and arthropods, which are common around building perimeters and fence rows. American cockroaches, crickets, ants and other insects will all eagerly attack these grains, as do slugs and snails. By elevating the baits off the floor of the bait stations with securing rods, block baits become less susceptible to attack from these “non-target” invertebrates. Moreover, elevated baits are protected from the water puddles that commonly form on station floors. As a result, bait replacement intervals are maximized because the bait remains fresher longer. (In general, baits should be re placed at least every 6 weeks on a need-it-or-not basis). In turn, you can demonstrate to your customer that less pesticide is being used on an annual basis for the account — an important message in the current trend of integrated pest management.

AVOID A BAIT MELTDOWN. One of the disadvantages of securing baits with horizontal rods is the problem of “bait meltdown” of blocks off of the securing rods during hot weather. (Bait meltdown occurs especially rapidly when thin “twist ties” wires are substituted for rods to secure the blocks). To respond to this problem, manufacturers are now offering vertical securing options whereby the blocks are held in place “standing upright.” This has led professionals to ask “why not use the vertical format all year long?”

Personally, I prefer the horizontal format for those stations that are not prone to bait meltdown, or using the vertical format only during the summer months, and in only those stations subject to the intense heat. This is because the horizontal format provides greater protection from both insect attack and contamination from wetness. Though it is true that insects feeding on baits can also be controlled by applying a wettable powder insecticide to the interior and exterior areas of the stations. Furthermore, puddles can be minimized by drilling drainage holes in the base of the station. However, these efforts require additional work and materials.

Securing bait packets inside stations can be done by using ordinary black paper binder clips to bind bait packets to the tops of the interior walls of the stations. Secured or not, however, some rodents do not readily gnaw into these packets, and small holes should be punctured into the packets to facilitate maximum interaction by incoming rodents. Once opened, the packets are now subject to spillage and pellets being moved about. In short, block baits are a better way to go. That said, secured packets are certainly far more desirable than unsecured packets.

A NO-LOSE SITUATION. Regardless of the method, the important point is to utilize bait-securing practices for your commercial and sensitive accounts. It’s not a lesson you want to learn the hard way. For instance, at a large and prestigious food plant this past summer one Norway rat had systematically visited, collected and carried out and off the bait blocks from seven exterior bait stations (spaced at 50-foot intervals) along the plant’s exterior wall. The rat cached all the blocks together beneath a vinyl cover at a raw product receiving bay door. To those of you who service food plants, you can appreciate that this was a bullet that food company does not wish to ever dodge again. Nor does the contracted pest control company, I’m sure.

Bait securing practices provide greater effectiveness and efficiency to your baiting programs, greater protection for your clients and their “products,” and dramatically reduce the hazards associated with baiting programs. In other words, bait securing practices are more environmentally friendly and in line with IPM. And because it requires little extra effort or money, how can we justify not implementing this practice for urban environments?

Dr. Robert Corrigan, one of the country’s leading rodent experts, is president of RMC Pest Management in Richmond, Ind. To contact Dr. Corrigan, call 765/939-2829