The Thurston County Board of Health approved the Integrated Pest Management (IPM) and Prescription Approval Process to regulate pesticide usage on county properties and properties managed by the county or its contractors.
Kimberly Graham, Hazardous Waste Specialist II, and Stuart Whitford, Thurston County point of contact for Lakes Management District, briefed the board on the history and mechanism of the prescriptions at a meeting on Tuesday, March 11.
IPM policies identify, understand, monitor, and prevent pests and employ different techniques to remove them.
“The public was concerned about the county's use of pesticides. Public concern really started ramping up in the 60s … the county responded by adopting an IPM policy aimed at setting an example through pest and vegetation management programs that when done correctly … actually reduces pesticide use,” Graham said.
“The level at which pests become an economic threat, that is when it's critical to guide future pest control decisions,” Graham added.
The main approach is manipulating the environment to discourage pest activity or introducing biological controls that naturally outcompete pests.
Only when the natural preventative approaches fail will the use of the safest, least toxic and most effective chemical treatments be acceptable.
“When treatment becomes necessary … that's when the action threshold has been met and none of your other preventative measures have done any good, then you start looking at chemical controls,” Graham said.
The county’s Environmental Health Department reviews all proposed pesticides and assigns a rating of either passed, conditional or failed. Conditional or failed status requires a higher degree of review and approval.
A meeting document stated departments managing pests or vegetation must develop a written IPM program that is approved by the Board of County Commissioners and reviewed annually by the Pest and Vegetation Management Advisory Committee (PVMAC).
Written IPM programs include a description of responsibilities and properties maintained, operational guidelines and standards, prescriptions/plans, public notification process for pesticide applications and record-keeping.
“With the prescriptions, we take all that into consideration when someone presents us with a new prescription,” Graham said.
The Environmental Health Department makes the first decision on the prescription and forwards it to PVMAC, and then the Board of Health for review.
PVMAC evaluates the pesticide hazard reviews conducted by Environmental Health, makes program recommendations on IPM prescriptions, and provides recommendations to the Board of Health on the adoption of prescriptions.
The board reviews criteria to determine whether the pest and vegetation problem has been assessed and the action level has been met.
The board also reviews the necessity of the use of the pesticide as an element of the integrated pest and vegetation management prescription, and the risks to public health, groundwater and the environment.
To safely handle weeds on bodies of water, the county has an Aquatic Nuisance Weed Control Prescription that sets a list of pesticides (currently all herbicides) that are approved for use on the four lakes in the county.
The prescription applies to the four county lakes with Lake Management Districts (LMD) — Long, Lawrence, Pattison and Offut lakes — formed under RCW 36.61.120.
The prescription also improves the timeliness of treating the lakes, as treatment can be given as soon as a listed weed presents itself in a lake.
“The goal of this program … is to protect beneficial uses and the natural environment (of) the lake while maintaining a balance between habitat, water quality, recreational and aesthetic values,” Whitford said.
The meeting document stated the intention of the program is not to eradicate native plants, but to lower excessive and sometimes dangerous plant densities while preserving a healthy ecosystem.
Whitford highlighted that some of the impacts nuisance levels of weeds cause are impaired water quality, threats to public safety, reduced access to swimming, decreased boating and fishing opportunities, reduced fish and wildlife habitat, and sometimes unpleasant odors.
Lakes having nuisance species, which have reached the action level described in table 1 of page 21 in the meeting document, must be treated with the prescribed treatment techniques on page 22.
Action levels are the thresholds at which control measures must be taken to avoid injury levels, and these vary according to the plant species in each area and the density or dominance of the plants.
Mechanical techniques, which are the first resort, include harvesting, mechanical rotovating and diver dredging.
Prevention and dredging are the cultural techniques, while the usage of specially formulated herbicides is the chemical technique.
There are currently no available biological control techniques for submersed vegetation in Thurston County lakes.
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jackmerrigan
This prescription violates the current IPM policy. The policy calls for the least harmful to the environment. That would be the physical removal of the noxious weeds. The policy does not say you can use pesticides if the physical control is too expensive. It seems that the county is pushing the easy button at the expense of the environment. Either change the prescription or the policy as they are incompatible.
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