The Agriculture Department has joined animal agriculture groups in raising concerns that EPA-proposed restrictions on rodenticides will increase costs for producers but not provide effective control of rats, mice, moles, and other vermin.

The EPA issued proposed interim registration decisions in November for three classes of rodenticides: first-generation anticoagulants warfarin, chlorophacinone, and diphacinone; second-generation anticoagulants brodifacoum, bromadiolone, difenacoum, and difethialone; and non-anticoagulants bromethalin, cholecalciferol, strychnine, and zinc phosphide.

The proposals, which address both consumer and agricultural use, include numerous mitigation measures to protect wildlife, including three endangered species that were chosen for a pilot project to assess the chemicals’ effects — the Stephens’ kangaroo rat, California condor and Attwater’s prairie chicken.

But animal ag organizations argue EPA’s proposals would increase costs and lead to ineffective rodent control, especially for smaller producers.

As part of the potential changes, the agency has proposed classifying rodenticides as restricted-use pesticides (RUPs) except for the pre-filled, single-use disposable bait stations designed to lure and trap pests. Reusable consumer bait stations smaller than one pound and their refills would no longer be allowed, and applicators of “loose” formulations such as pellets, meal baits, and treated grains would have to wear respirators.

In comments on the proposals submitted this month, USDA warned that “restrictions on the use of loose rodenticides during the growing season of registered crops and above-ground in pasture/rangeland would be devastating to U.S. agriculture, resulting in potential loss of rodent control, crop damage, and crop contamination. The agency’s rationale for these mitigations seems to diverge from established risk management practices for these uses, which have been effectively workable for decades.”

In a letter accompanying USDA's comments, Kimberly Nesci, director of USDA's Office of Pest Management, also argued that classifying all rodenticides as RUPs as well as removing field uses for certain active ingredients “may have serious consequences for farmers that are aggravated by the lack of currently labeled alternatives.”

EPA acknowledged that ag producers might face higher costs, in evaluating restrictions on chlorophacinone and diphacinone.

“Restricting spot, broadcast, and below-ground applications of (the two anticoagulants) in agricultural systems during the growing season would limit growers to (use of those) in bait stations, or their alternatives, (below-ground applications of strychnine and spot, broadcast, bait station, and below-ground applications of zinc phosphide) for chemical rodent control,” EPA said.

The agency also noted that bait stations “can be impractical, ineffective, and labor-intensive when treating larger fields.” Other approaches are either not permitted — such as strychnine for the control of above-ground pests — or potentially inadequate — such as broadcast applications of zinc phosphide.

“Users could face increased control costs as a result of this mitigation, and in some cases could suffer yield loss and reductions in product quality if remaining methods of rodent control are insufficient,” EPA said.

USDA's OPMP also noted changes in RUP status “could affect almost any agricultural operation needing targeted structural or field rodent control but is most likely to affect smaller and/or independent operations who may be more likely to make applications in-house.” 

The nation's livestock groups — informally grouped into the so-called Barnyard Coalition — say the proposal would introduce new costs and concerns.

“We’re really worried that there's a lot of places where you just won't be able to get good certified applicator service, particularly if they have to come inside the animal houses because then you have biosecurity risks,” Tom Hebert, a consultant who works with several of the animal ag groups that signed onto the comments, told Agri-Pulse. Hiring a certified applicator or having someone certified in-house also is more expensive than the way farms and ranches have been practicing rodent control for decades.

Coalition members signing off on the comments included the American Farm Bureau Federation, National Milk Producers Federation, National Council of Farmer Cooperatives and United Egg Producers. The coalition is “worried that it's going to hurt people's ability to control rats and mice,” said Hebert, who was USDA's deputy undersecretary for natural resources and environment from 1994 to 1998. 

The groups, which also include the National Cattlemen's Beef Association, National Pork Producers Council and National Turkey Federation, want EPA to consult with the Food and Drug Administration and USDA's Animal and Plant Health Inspection Service before moving forward with the proposed changes. 

In comments to EPA, the coalition said it’s “essential that before the agency reaches final decisions on these (proposed interim decisions) that the policies be the subject of an interagency review and clearance process” comparable to other significant rulemakings that undergo Office of Management and Budget review.

“FDA and USDA should definitely be brought into the mix on this,” said Clay Detlefsen, senior vice president of regulatory and environmental affairs at NMPF.

The animal ag groups note that the law governing the interstate shipment of milk, the Pasteurized Milk Ordinance, “suggests rodenticides as a possible tool to use for the control of rodents, including anticoagulant poisons such as Warfarin and Fumarin.

“Rodent control is required by the FDA as well as state food safety mandatory controls applicable to dairy and table egg production.” their comments state. “Rodenticides are in widespread use today on animal agriculture operations as the primary tools used to control rodent populations and meet these federal and state on-farm food safety requirements.”

Producers don’t want a certified applicator who has already visited other operations walking through their barn, potentially contaminating the animals, Hebert said.

Don’t miss a beat! It’s easy to sign up for a FREE month of Agri-Pulse news! For the latest on what’s happening in Washington, D.C. and around the country in agriculture, just click here.

“They’ll be worried about biosecurity, and what will happen is, they'll get an explosion of a rat population, which is unavoidable,” he said. “And then they have to put up a bunch of bait in order to get that population under control. And so rather than controlling a population of 100 or 200, rats, you're controlling a population of a couple thousand.”

Tom-Hebert.jpegTom Hebert

Environmental groups concerned about the welfare of endangered species offered a different perspective.

The Center for Biological Diversity said EPA still has not evaluated the impacts of rodenticides on 91 other species listed as threatened or endangered, and that simply designating anticoagulants as RUPs would not “avoid exposures and deaths of non-target organisms, including ESA protected and rare wildlife.”

CBD also recommended canceling all second-generation anticoagulants or SGARs, because they “pose an unreasonable adverse effect on the environment and public health.” SGARS, CBD said, should be allowed only “as a last resort during demonstrated public health or environmental emergencies for a period not longer than 30 days.”

Joanna Fitzgerald, director of the von Arx Wildlife Hospital at the Conservancy of Southwest Florida, said “anticoagulant rodenticide toxicosis is often fatal by the time an animal arrives at our facility. Harmful rodenticides are affecting the predator/prey balance by destroying nature's own rodent-control system. Loss of non-target, predatory species is negatively affecting the balance needed for healthy ecosystems.”

For more news, go to