Proposed rule changes for restricted-use herbicides

SprayerFrom WSU’s Wheat and Small Grains website

The Washington State Department of Agriculture (WSDA) is considering rule changes affecting the use of restricted-use herbicides. The possible rule changes were agreed upon by a workgroup consisting of representatives from Washington State University (WSU) and various agricultural sector representatives, including the Washington Association of Wheat Growers. The existing rules covering restricted-use pesticides are extensive, complex and confusing. For example, there are more than 50 different established areas in Eastern Washington, each with their own restrictions. Some of the existing rules are more than 50 years old and lack relevancy in today’s agriculture. For example, current rules require nozzles with a minimum orifice diameter, but current nozzle manufacturers and pesticide labels refer to the size droplet spectrum produced by a particular nozzle type at a specific pressure. The current rules also limit spray pressures below that needed by modern nozzle types such as air induction nozzles. The purpose of the proposed changes is primarily to repeal redundant and very outdated rules. The proposed new rules do not impose any additional regulatory requirements and WSDA does not believe the changes will pose any increased risk to sensitive crops. WSDA is seeking public comment on the proposed rule changes before filing an official rule-making proposal sometime in the fall of 2017.

The Department is considering the following changes:

  • Amending nozzle and pressure requirements in the three WAC chapters to reflect current standards that applications must be made by creating a droplet spectrum size (e.g., medium, coarse or very coarse) that is in conformance with ASABE (American Society of Agricultural and Biological Engineers) standards;
  • Repealing the 85 degree Fahrenheit cut-off requirement in individual county rules since it is in the statewide rule (redundant);
  • Repealing maximum wind speed restrictions in individual county rules and adding a maximum 15 mph wind speed restriction to the statewide rules;
  • Repealing restriction in statewide rules that limits the addition of oil carriers and adjuvants to one pint per acre;
  • Repealing restrictions in individual county rules that prohibit use of oil type carriers for brush control during certain times of the year;
  • Repealing restriction in statewide rules that prohibits mixing, loading and equipment decontamination (also aircraft takeoff and landing) in a manner that causes damage to susceptible crops;
  • Repealing restrictions in counties and specific “Areas” of counties that limit mixing loading of aircraft to formulations that can be applied in the Area where the airstrip is located;
  • Repealing the prohibition in statewide rules on turning or flying low over cities, towns, residences and other sensitive sites;
  • Repealing the prohibition in the statewide rules for storing use-restricted herbicides in “Areas” where their use is prohibited unless they are in a sealed container and the outside of the container is not contaminated; and
  • Repealing the provision in the statewide rules that indicates application of use-restricted herbicides through irrigation is subject to the same requirements as ground applications except for nozzle size and pressure requirements.

The Preproposal Statement of Inquiry provides details on how interested parties can provide comments on the proposed rule changes to WSDA. The Explanation of Possible Rule Changes explains the proposed rule changes and why the changes are deemed beneficial. This is a good-faith effort to simplify and update rules related to the application of restricted use herbicides. Please consider providing your thoughts on the proposed rule changes to the Washington State Department of Agriculture.

For questions, contact Drew Lyon by phone at 509-335-2961 or by email at

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