Rodenticide Bait FAQs

A: Colored droppings indicate a rodent has ingested and digested the bait and its active ingredient. It takes several days for most baits to kill a rodent. Mice produce upwards of 50 or more droppings every day; rats produce 30 to 40. Thus, some droppings will be passed through the body containing the green, blue or red dye of the rodent bait. The rodents that produced the colored droppings are usually dead by the time the colored droppings are noted inside the bait station or they are likely to be near death.

A: Most recommendations suggest changing out rodent baits on a four- to six-week schedule on a need-it-or-not basis. In cases of maintenance baiting and in low-risk situations (i.e., not protecting a food plant or some other sensitive account), if the bait has remained undisturbed by dirt, dust or moisture, change-out periods may be extended to slightly longer periods as determined on a case-by-case basis. Very moldy or decayed baits are unattractive to rodents and thus may not be any better than no baits at all. In most cases, it is most time-efficient to err on the side of overprotecting the area with the freshest baits.

A: Several factors may affect the time to death, but it varies from rats and mice and from the particular active ingredient used. Rodents subjected to those compounds with low LD50 values tend to die sooner than those with higher values. But it also depends on specific colony factors. In general, anticoagulant baits can produce death as early as three days, but in some cases it may take up to 18 days. For practical infestations, it is best to be conservative and inform clients that it could take seven to 10 days before the first rodents succumb and cease activity. Severe infestations may require three to four weeks to achieve a high level of control.

A: In general, a pest professional should never "lose control" over the pesticides they apply. Packet baits tossed into "inaccessible areas" can be moved by rodents to areas accessible by children, pets or wildlife. Baits abandoned in inaccessible voids may also cause grain insect infestations. Additionally, most rodenticide labels direct the user to not broadcast baits and to retrieve unconsumed baits.

A: In some cases, it may be crucial. In infestations where rodents may have readily available food sources to them, they have the option of rejecting new-appearing foods that have chemical tastes. It makes sense to maximize the palatability of grain-based baits. Rats can taste chemicals in their food in parts per billion. Thus, it is smart to prevent rodenticides from becoming contaminated with chemical odors, as well as from nicotine residues from the fingers of technicians who smoke.

A: Poisoned rodents may die anywhere, including in some inconvenient areas. There is no evidence the rodents exit buildings "seeking water" and die outside, although this would be convenient for all parties. Most times, poisoned rodents succumb in their nests. It is also common to find rodents dead (or near death) in bait boxes.