Abandoned Baits In Buildings

In efforts to control these difficult-to-access populations, baiting programs involve applying either packets or bait blocks into the “inaccessible areas.” Unfortunately, because accessing these areas can be time consuming, frustrated technicians sometimes toss the baits into the various voids, apparently with no concern for retrieving the baits.

But an important question arises here: Should baits that cannot be retrieved inside occupied buildings be applied? Probably not. Let’s examine why.

First, of course, is the pesticide label and thus the law. Nearly every rodenticide label states “collect and discard of all leftover bait.” Moreover, most labels also state that broadcasting the bait is not allowed. These label directions are based on important concerns. There are potentially hazardous consequences to abandoning baits in buildings. Loose baits that have been placed, dropped or tossed (i.e., broadcast) into building spaces, may be picked up by rodents and moved or carried to areas where they may in one way or another later become accessible to people and pets.

In some situations this can have serious implications. Consider the long-term potential hazards of abandoned baits in schools, health care facilities, restaurants and other types of accounts where sensitive situations exist, or where food may be stored, prepared or served. Many real world case histories exist. However, one case of an unprotected bait packet that found its way onto a child’s lunch tray in an elementary school should suffice.

Too, it is not a rare occurrence for repair personnel and homeowners to have had baits literally drop on their heads when removing suspended ceiling panels. There are also repeated cases of remodelers and construction crews collecting up to 40 pounds and more of packet and block baits that were applied, re-applied and re-applied on top of previously abandoned baits in ceilings, attics, walls and floors. It may be a stretch to assume these personnel dispose of the rodent bait in a manner approved by the labels, or, in fact, in any manner which would not present a hazard to non-target animals or the general environment.

Abandoning rodent baits in buildings also presents an ethical concern. Because rodent baits are made of food quality grains, flavor attractants, seeds, etc., there are many cases of “mysterious” stored product pests (e.g., Indian meal moths, cigarette beetles, black carpet beetles and others) suddenly erupting within homes, high-rise complexes, shopping malls, restaurants and office complexes. A common source of stored product infestations are loose bait packets that were carried off by a rodent to an inaccessible void, or from baits tossed and abandoned by a homeowner, PCO or janitor.

In one home I investigated, black carpet beetles were repeatedly attacking valuable woolen clothes and rugs throughout the bedrooms and closets of the upstairs bedrooms. Upon inspecting a difficult-to-access attic, I discovered about 25 packets of partially consumed rodent meal baits applied by a previous PCO. Most of the packets also contained black carpet beetles. Hmmm.

Smart Solutions. Controlling mice and rats in difficult-to-access areas can be challenging — no doubt about it. But there are better strategies than tossing baits to these areas and then abandoning them.

When infestations are occurring in large commercial situations, the large structural voids (e.g., crawl spaces, sus-pended ceilings) are rarely uniformly infested. Usually infestations concentrate along specific runways and around certain pockets nearby areas where rodents have easy access to food or other resources. Based on the results of a good inspection, these high-activity areas should be specifically targeted for baiting.

Ideally, baits should be installed within numbered bait stations which will contain a bait block (of which there are several on the market). Simply take a moment to record the number of the stations in a room or area on a sheet. For example: “Stations Nos. 1-6 along perimeter of suspended ceiling in break room.” Upon program completion, consult the location guide and remove the pesticides. Noting which rooms do not contain stations e.g., “No stations located in any of the ceilings in rooms 14-17,” is also a valuable timesaver.

Loose baiting programs per se are not necessarily wrong, if applied to label directions. In fact, in cases where severe infestations of large voids are occurring (attics and crawl spaces) and it is not practical to install bait stations, baits can be installed in a loose bulk format. But here too, a location sketch map, or simply just keeping records of the numbers of the blocks or packets applied should be made, and the baits retrieved when the program is completed.

In rodent-active areas where physical access or installing bait boxes is impossible, block baits can be strung on a fishing line or wire, and dropped or tossed into infested areas. The wire can be nailed or tied near the point of access for the professional, and used to retrieve, or replenish the baits as needed. For buildings where infestations are persistent due to incoming rodents from surrounding areas or buildings (as with inner-city areas), follow the label and establish permanent bait stations, or permanent secured bait, i.e., wired bait.

Retrieving baits from buildings upon program completion extends courtesy to those pest management professionals whom may at a later time follow you. Inheriting liability from a previous “professional’s” misuse of a pesticide has been a concern of our industry for many years.

Be courteous. Be professional. Don’t abandon rodenticide baits.

Dr. Robert Corrigan is president of RMC Pest Management Consulting, 5114 Turner Road, Richmond IN 47374, 317/939-2829.