Rodenticide Hazards

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Rodents have long been a challenge for humankind. They are highly adaptable to human development, cause damage to our crops and homes, carry diseases that can make us sick, and are capable of reproducing at a significant rate.

For as long as humans have been living with rodents, we’ve been developing ways to control them.

There are currently various methods to control nuisance rodents at home. Such methods include changes in cultural practices, deterrents, traps, and chemical poisons (rodenticides). All of these methods are effective at controlling nuisance rodents, but there has been a trend toward greater reliance on the use of rodenticides. Rodenticides are often considered the most cost effective method to control rodents, but they also present the greatest risk to public health and the environment. Rodenticides are often the cause of unintentional poisoning via direct ingestion by domestic pets or children, and indirect secondary poisoning of non-target species including domestic pets and predatory wildlife. Secondary poisoning most often occurs when a non-target species eats a rodent that has eaten rodenticide. 

While all rodenticides present a public safety and environmental health risk, certain rodenticides known as Second Generation Anticoagulants (SGAs) are of particular concern. These rodenticides are known to be a significant cause of secondary poisoning of non-target species. Since the early 1990’s, SGA Rodenticide residue has been detected in liver tissue samples of 70 – 90% of over 300 non-target wildlife species screened and has been restricted in 2014 by the California Department of Pesticide Regulation.  SGA rodenticides are no longer available for purchase at retailers and can only be applied by licensed pesticide applicators. While this has reduced the use of SGAs, they are still widely used by pest control companies at homes and business throughout Davis. In Davis we see the continued effects of secondary rodenticide poisoning every year as many locally collected dead raptors test positive for the presence of rodenticides.

So, what can a concerned citizen or property manager do to reduce the exposure of local wildlife to anticoagulant rodenticides? To start, we recommend that you avoid using rodenticides to control rodents and employ alternative methods instead. If you use a pest control company, communicate with them your desire to control rodents without using rodenticides. Finally, share your concerns about secondary rodenticide poisoning with your neighbors.

Resources:

California Department of Fish and Wildlife 

Raptors are the Solution (RATS)

U.S. Environmental Protection Agency