New EPA Proposed Interim Decisions PIDS on Pyrethrins and Piperonyl
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Pyrethrin Issue

• EPA is issuing a Proposed Interim Registration Review Decision for Pyrethrins.
  • This type of decision may determine new risk mitigation measures are necessary or layout interim risk mitigation measures or ID data or information needed to complete review.
  • They issued this PID so they can move forward with aspects of the registration review that are complete and implement interim risk mitigation.
• Pyrethrins are one of a few insecticides that are allowed to be used in organic livestock production.
• Products containing pyrethrins are recommended for use in animal housing (presises poultry houses, stables barns dairy housing). They are also used in direct application to livestock for the control of nuisance pests and disease vectoring pests (mosquitoes and ticks)
• EPA has identified potential risks for concern
  • Residential and occupational handler exposure
  • Potential ecological risks for pollinators and aquatic invertebrates from outdoor agricultural use.
• Proposed Restrictions
  • Proposing to cancel the registrations of certain products for which no other mitigation strategies are available. Given the availability of effective alternatives including alternate formulations of the other pyrethrin products the EPA concludes that the cancellation of these products would not result in significant loss of efficacy or economic impacts for the users.
  • Prohibit application via misting systems for the use in animal barns (due to inhalation),
  • Addressing the risks of concerns to occupational applicators
    • EPA proposes to prohibit the use of liquid trigger spray bottles for applications directly to companion animals and livestock
    • EPA proposes to prohibit the use of ready to use dust shaker can products for direct application to livestock.
    • EPA proposes to prohibit pressurized liquids and aerosols applied directly to livestock
    • EPA Proposes to prohibit application with mechanically pressurized handguns to livestock direct treatments or livestock housing/poultry house/horse barns/feedlots.
    • EPA proposes to require PF10 respirators for applicators applying liquid dip applications directly to livestock, for mixer/loader or applicators in housing or manual pressurized hand applicators in livestock housing
    • Assumption- The impact of the proposed respirator requirement is likely to be substantially lower in many situations because a professional applicator will likely have respirators and be fit tested because they already use other chemicals requiring respirators. Livestock operations are most likely to be affected.
    • EPA is proposing to add fit testing, training and medical evaluation requirements for all labels.
    • Recommend wipe or spot on products.
    • EPA acknowledges that the loss of misting system in use settings such as barns may make pest control more difficult and costly since the alternatives may be more expensive, require repeated applications because of the loss of efficacy or may be limited to spot treatments from which pests can escape more often.
• Synergistic effect of Piperonyl Butoxide and Pyrethrins.

Key Points

• The equine industry in the U.S. has a limited set of options for ectoparasite control on and around horses. The overwhelming majority of currently available ectoparasite control products labeled for use on horses contain either pyrethrins or piperonyl butoxide (PBO) or both as the primary active ingredients.
• The most commonly used application methodology for these products is direct application to the horse by handheld spray bottle and most products are sold in spray bottle form only.
• Vector control on equids and on equine premises in the U.S. has two primary goals: 1) prevention of vector-borne disease transmission to equids by biting flies, mosquitos, ticks, and other biting insects, and 2) prevention of the stress and welfare impacts to the horse caused by “fly worry” – the necessity for horses to constantly swat, stomp, skin twitch, head shake, and move in response to being bitten and bothered by flying insects.
• The use of pyrethrins and/or PBO for the purposes of vector-borne disease prevention in equids is industry standard. Specifically, some of the key diseases being prevented with these products include Equine Infectious Anemia (EIA) and Vesicular Stomatitis (VS) transmitted by biting flies, Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), and West Nile Virus (WNV) transmitted by mosquitos, and Anaplasmosis, Equine Piroplasmosis (EP), and Lyme Disease transmitted by ticks. Moreover, in cases of the federally regulated diseases EIA, VS, and EP, USDA protocols require vector mitigation measures including direct application of insecticides labeled for use on horses be implemented as part of the disease response.
• Additionally, the American Association of Equine Practitioners’ (AAEP’s) ectoparasite guidelines for veterinarians recommend pyrethrins and/or PBO as the most widely available products for safe and effective control of ectoparasites on horses.
• While there are currently a very small number of available products labeled for use on horses that do not contain pyrethrins or PBO as an active ingredient, there are not enough of these options nor are they currently produced in sufficient volumes to replace the use of direct spraying of pyrethrins and/or PBO products on equids.
• The use of misting systems in equine barns and facilities is widespread throughout the industry. These systems are most commonly used in equine veterinary hospitals, large boarding facilities, and private racing and show barns.
• There are limited pesticide options currently available and labeled for use in these misting systems for equine. The majority of the available drum-volume options use either pyrethrins and/or PBO as the active ingredient for hook-up to these systems.