Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 1 of 13 

# WASHINGTON COUNTY

OREGON

DEPARTMENT OF HEALTH & HUMAN SERVICES

Environmental Health Division



## A RBOVIRUS 

## M ANAGEMENT 

## P ROGRAM


### 2009 Pesticide Use Plan

PART I: DESCRIPTION OF THE ARBROVIRUS MANAGMENT PROGRAM

The Washington County Arbovirus Management Program was initiated in 2003 in anticipation of the arrival of West Nile Virus (WNV) in Oregon, first identified in the United States in 1999. The current program is a cooperative effort between Washington County and Clean Water Services (CWS), Tualatin Hills Park and Recreation District (THPRD), Beaverton School District, and local cities. Participating citie s include Beaverton, Cornelius, Forest Grove, Hillsboro, Tigard, Tualatin, and Sherwood. Program roles and responsibilities are defined in Intergovernmental Agreements (IGA).

The role of Washington County is to:
3⁄4 Coordinate efforts to meet the goals of the Oregon Department of Human Service’s Public Health Emergency WNV Response Plan.
3⁄4 Coordinate public health education related to vector-borne disease and mosquito biology throughout Washington County.
3⁄4 Work with state and local agencies to track WNV cases.
3⁄4 Design and implement a mosquito surveillance program and provide training to IGA partner agencies and county staff.
3⁄4 Provide larvicide product to IGA partner agencies to treat publicly owned sumped catch

basins.
3⁄4 Identify mosquito habitats based on surveillance and advise IGA partner agencies of appropriate preventative and control measures for properties under the control of the IGA

partner. 3⁄4 Identify mosquito habitats in areas of the County not under the control of an IGA partner

agency. 3⁄4 Implement mosquito prevention and control measures in areas not under control of IGA partners which includes: managing and limiting standing water, promoting the removal of decaying organic debris, promoting natural pr edators, distributing Gambusia affinis, treatment of natural water habitat, and treatment of private and publicly owned sumped catch basins up to two times per season.
3⁄4 Maintain a database mapping all identified mosquito habitats, surveillance records, complaints, and mosquito control work within the County.
3⁄4 Process and test adult mosquitoes and dead birds for WNV3⁄4 Number and identify species of larval and adult mosquitoes
3⁄4 Report product treatments to the Oregon Depa rtment of Agriculture (ODA) following Pesticide Reporting System (PURS) guidelines

The role of all IGA partners is as follows:
3⁄4 Utilize and distribute public education materials developed by the County and actively educate the public.
3⁄4 Report mosquito and bird complaints to the County
3⁄4 Identify and treat publicly owned sumped catch basins within the IGA’s area of control.
3⁄4 Deliver larval and adult mosquito samples to the County for identification and or testing.
3⁄4 Implement mosquito prevention and control measures as recommended by the County, which includes managing and limiting standing water, removal of decaying organic debris, promoting natural predators, and treatment of publicly owned sumped catch

basins.
3⁄4 Report product treatments to the Oregon Depa rtment of Agriculture (ODA) following Pesticide Reporting System (PURS) guidelines

BUDGET

This program utilizes resources provided by the County, IGA agencies, and grant dollars. The County budgeted $388,000 general fund dollars to this program in the 2008-2009 fiscal year. The same level of support is expected for the 2009-2010 fiscal year. Partner organizations provide in-kind labor resources. In addition, Clean Water Services provides lab space for mosquito identification and WNV testing. Inter-Governmental Agreements (IGA) have been renewed through 2011.

SIZE OF JURSIDICTION

The County covers 727 square miles. Most program activities are planned to take place within the 118 square miles Washington County Urban Growth Boundary (see map 1). The program will lay emphasis on prevention and control of mosquito species known to be competent vectors.

TRAINING

The Washington County Mosquito Control Coordina tor is responsible for training the IGA staff in surveillance and control. Training focuses on mosquito biology and ecology, surveillance techniques, mosquito species-specific control methods, and arbovirus risks. Training is conducted before the start of the mosquito-monitoring season and will continue on an as-needed basis throughout the season. The County Mosquito Control Coordinator has completed all necessary continual educational hours for recertification purposes. The Coordinator will attend trainings when applicable through out 2009.

2008 YEAR END REPORT (See attachment)

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 2 of 13PART II: SURVEILLANCE

Washington County and IGA field staff invol ved with the Washington County Arbovirus Management Program conducted active larval and adult mosquito surveillance in 2008. Washington County mosquito control workers and IGA field staff inspected 434 potential mosquito habitat sites (as shown in Map 2). The role of Washington County mosquito control workers and IGA field staff is to:
3⁄4 Collect mosquito samples for identification and encephalitis testing
3⁄4 Document surveillance information including: Potential habitat breeding locations Presence of mosquitoes at sites

Identified habitat risk Verification of property ownership

In 2009, the County will continue to identify additional breeding sites and implement appropriate prevention and control efforts to minimize mosquito populations located within Washington County.

PART III: MAPPING

Washington County maps and catalogues:
3⁄4 Sensitive water areas
3⁄4 Adult trap locations
3⁄4 Larval sampling sites
3⁄4 Mosquito specie distribution and diversity
3⁄4 Encephalitis case sites
3⁄4 Dead birds reported and tested
3⁄4 Gambusia Affinis distribution sites
3⁄4 Mosquito complaint phone calls
3⁄4 Surveillance data
3⁄4 Pesticide usage
3⁄4 Locations receiving larvicide or adulticide applications (treatments for the year are submitted to Oregon Department of Agriculture, as required)

A map and list of sensitive areas, as identified by the Oregon Department of Fisheries and Wildlife (ODFW), located in Washington County has been attached at the end of this document. If further documentation is needed for any submitted maps, please contact the County’s Environmental Health program. (See attached 2009 Sensitive Areas)

PART IV: TREATMENT

Washington County will use Integrated Pest Management (IPM) as an effective and environmentally sensitive approach to mosquito management. Washington County will use current, comprehensive information on the biology and ecology of mosquito life cycles their interaction with the environment. This information, in combination with available control

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 3 of 13methods will be used to manage mosquito populations with the least possible hazard to people, property, and the environment.

Larvicide selection and time of application will be based on the distribution and behavior of the target mosquito species, environment, and weather conditions. Adult vector mosquito control in the County will only be conducted in the event of a public health emergency and be based on environmental conditions, adult vector mosquito abundance, and/or virus isolation in tested mosquitoes, the magnitude of infection in birds, horses, human cases of arboviral disease.

In 2008, larval vector mosquito control activities primarily focused on publicly and privately owned sumped catch basins within the Washington County Urban Growth Boundary (see map 1) and high-risk natural water habitats.

There are approximately 23,230 sumped public catch basins in Washington County with a high potential to breed mosquitoes. In 2008, Washi ngton County and IGA fiel d staff treated about 21,975 sumped public catch basins and 1,267 private catch basins with Altosid XR briquettes. It is anticipated that the number of treated catch basins will remain the same or increase as more sumped public and private catch basins are identified.

Refer to the attached 2008 Year-End Report for detailed information regarding vector mosquito control activities conducted at sumped catch basins and natural water habitat by Washington County and IGA field staff.

In 2009, Washington County will continue to follow the Oregon Department of Human Services Public Health WNV Emergency Response Plan to respond to different West Nile Virus threat levels at natural water habitats based on local surveillance findings. Response will be based on cases of arbovirus illness detected in the County, vector mosquito abundance, environmental conditions and habitat, weather, and the proximity of detected vector mosquitoes to densely populated areas within the County.

In 2009, the County anticipates routine surveillance and larvaciding at sumped catch basins, water quality facilities, and natural areas with in Urban Growth Boundary. The County will increase knowledge related to mosquito species and breeding sites within the County through

adult and larval surveillance.

Areas inspected, monitored, and treated in 2009 will be mapped and recorded. Adulticiding will be used only in the event of a public health emergency. All adulticide and larvicide applications will be documented in the County’s database. Updated maps containing new site locations will be submitted to ODHS and ODFW each season and when requested.

Pesticide applications and other records will be maintained in the County database and in a hard copy filing system.

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 4 of 13PART V: USE OF SURVEILLANCE TO DEFINE THE PROBLEM AND

DETERMINE PESTICIDE OF CHOICE

Larval Surveillance

Standard 4-oz dippers will be used to conduct surveillance of mosquito larvae and pupae. Washington County mosquito control and IGA field staff will sample aquatic sources including: natural and manmade wetlands, ponds, sumped catch basins, drainage ditches, canals, and other standing water using standard 4-oz dippers. The County Mosquito Control Coordinator and/or trained staff will identify species and population numbers in submitted samples.

The threshold to determine treatment will be one mosquito per dip for species with high capacity to vector arbovirus for example, but not limited to, Culex tarsalis

, Culex pipiens , and Culex stigmatasoma . Five (5) mosquitoes per dip will be the standard threshold to determine treatment for species with a low capacity to vector Arbovirus for example, but not limited to, Aedes

vexans , Coquillettidia perturbans , and Culiseta inornata

.

Washington County, for the most part, will limit control activities to mosquitoes species identified as potential vectors of arbovirus. If additional potential vector mosquito species are identified they will be targeted for control as needed.

In 2008, sumped catch basins were treated with Altosid XR, which inhibits larval mosquitoes from emerging from the pupae stage. A set number of sumped catch basins are monitored for efficacy and residual time to determine if and when additional treatment is required. Other mosquito breeding sites will be treated with V ectoLex CG, Vectobac G, Altosid Pellets, Agnique MMF or Golden Bear based on surveillance findings. In these areas, a subset of the sites will be periodically monitored 24-72 hours after treatment, to determine a follow up treatment schedule and to monitor product effectiveness.

Evaluating efficacy of treatment

A representative number of sites treated for mosquito production will be sampled 24-72 hours post-treatment using standard measures. The number and developmental stage of larval mosquitoes sampled will be compared with pre-treatment numbers for that site. A representative number of sumped catch basins treated with Altosid XR (Methoprene) will be sampled 24-72 hours post-treatment and every two (2) weeks thereafter. Live pupae samples will be collected and transported to the lab to determine efficacy.

Non-target effects

Washington County will rely on published scientific materials as well as label directions to minimize the impact on non-target organisms. Washington County Arbovirus program does not have the capacity at this time to conduct and analyze impacts on non-target organisms. Washington County will rely on published studies of non-target effects to determine larval control strategies.

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 5 of 13Documenting sampling results for annual repor t:

Larval sampling results are maintained in the County’s database and hard copy files. Information includes the species, stage, instar (where applicable) and number of mosquito specimens collected in each location. All mosquito collection information will be included in the Year-End Report and sent to ODHS and IGA fi eld staff involved in mosquito collection as

needed.

Adult Surveillance :

Adult mosquitoes will be monitored using Carbon Dioxide (CO 2 ) baited Encephalitis Vector Surveillance (EVS) traps and Gravid traps. The County Mosquito Control Coordinator and/or trained staff will identify species and populations numbers in submitted samples. Adult surveillance will be conducted from May through October. Testing for West Nile Virus will be done using the Rapid Analyte Measurement Platform (RAMP) in the County lab and/or sent to the Oregon State Public Health Lab for testing, as needed. Public complaints may be used to determine trapping locations but will not be used to determine adult mosquito control actions.

Sampling pre-treatmen t 3⁄4 To determine species Many areas in Washington County are monitored for adult vector mosquito populations by County staff and IGA field staff, using Carbon Dioxide (CO2) baited EVS traps and Gravid traps. In 2009, Washington County will be increasing the number of adult trap sites in the County. CO2 baited EVS traps and Gravid traps will be placed in selected areas to monitor adult mosquito activity. Data collected from mosquito samples will include species identification, number present, and test results, if done.

3⁄4 To determine population density Trapping adult mosquitoes will provide useful geographic information regarding the population density and species diversity of mosquitoes within the urban and non-urban areas of the County. Larval surveillance results will be used to determine population densities for species that are not readily attracted to adult surveillance measures.

3⁄4 To determine need for control As previously noted, adult mosquito management will be based on cases of Arbovirus detected in the County, vector mosquito abundance, environmental conditions and habitat, and/or the proximity of detected vector mosquitoes to more densely populated areas within the County.

Sampling post-treatment
3⁄4 To determine the efficacy adult mosquito traps will be placed in a select number of sites pre and post-treatment. Trapped pre-treatment mosquitoes will be placed in the targeted adulticiding area and then collected after the treatment application. The trapped mosquitoes will act as a “control group” to give an accurate calculation of the effectiveness of the treatment.

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 6 of 133⁄4 Efficacy, In-migration and Non-target effects At this time, Washington County does not have the capacity to monitor for pesticide resistance, in-migration, or effects of non-target organisms in more depth. To determine the proper control method for each situation and to minimize the impacts on non-target organisms, the County will rely on proper application techniques and published, scientific, and peer reviewed publications.

Document sampling results for annual report

Adult sampling results are maintained in the County’s database and hard copy files. Information includes the species and number of mosquito specimens collected in each location as well as any WNV RAMP and Oregon State Public Health Lab testing results. All surveillance information will be included in the Year-End Report and periodically sent to ODHS and appropriate IGA field staff. Information collected during the mosquito season will map potential breeding sites, target larvicide applications and arbovirus transmission risk.

Choice of Pesticide(s)

Larvicides:
3⁄4 Altosid Pellets
3⁄4 Altosid Water Soluble Pouch (WSP)
3⁄4 Altosid Briquets
3⁄4 Altosid XR Extended Residual Briquets (insect growth regulators (IGR))
3⁄4 Vectobac G
3⁄4 VectoLex CG

These larvicides have been chosen because they are biological pesticides, which release chemicals produced naturally and effectively control mosquito larvae populations. These products are known to have limited impacts on non-target organisms. Vectobac G and VectoLex CG will be the only larvicides used within a sensitive area as determined by Oregon Department of Fish and Wildlife. Agnique MMF or Golden Bear will be applied for pupae control if vector mosquito breeding areas show that the developmental stages of larvae have surpassed the ability to be controlled by the above listed larvicide products. Agnique MMF and Golden Bear will be used only as a surfactant to control pupae.

Adulticides:
3⁄4 Anvil 10+10 ULV
3⁄4 Pyrenone 25-5 Public Health Insecticide
3⁄4 Scourge Insecticide

Anvil 10+10 ULV a Synthetic Pyrethroid will be used for adult control around populated areas. Anvil 10 + 10 will be considered first if adulticiding takes place. Pyrethirins such as Pyrocide Adulticiding Concentrate and Pyrenone 25-5 Public Health Insecticide will be the second choice of use for populated areas. Although Pyrenone 25-5 Public Health Insecticide is among those that will be first considered for adult control, preventing applications directly to water or to areas where surface water is present will be closely monitored. As noted on the label, this restriction

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 7 of 13applies to “wetlands, ditches, irrigation canals, and any surface water areas that drain to or are connected either directly or by pumps to lakes and streams.” Scourge Insecticide with Resmetherin and Piperonyl Butoxide 18% + 54% may be used where there is an increased likelihood of OP resistance in the mosquito population, or where Pyretherin may not be effective. Scourge is highly toxic to fish and will not be directly applied to water, or areas where surface water is present, or areas where drift and runoff from treated sites may be hazardous to fish in adjacent waters. Adulticide products will be applied using ULV applications through a contracted source. It has been noted that the adulticides listed above have warnings against the use in waterways. Therefore, Washington County will strictly adhere to these requirements and

use extreme caution at all times when near or around water sources.

PART VI: MOSQUITO MANAGEMENT

Larvae Control

The purpose is to minimize disease transmission and the need for adulticide applications by managing vector mosquito populations before they become adults. To date, larvae mosquito control applications in Washington County include publicly owned storm water management structures, bio-swales/retention ponds, backyard habitat (when needed) and natural water habitats in the County. Established thresholds (previously noted) are in place based on a mosquito’s ability to transmit arbovirus disease (primarily West Nile Virus). The mosquito species targeted in disease transmission (primarily West Nile Virus) may change, as more information is made available. Established thresholds are subject to change as updated scientific information becomes available. Use of larvicide for control will be used when other options (i.e. source reduction, education, vegetation management) have been evaluated and/or attempted. Products used to control larval mosquitoes will be selected based on characteristics of the site including, but not limited to: organic concentration, species present, developmental stage of larva, length of control time desired, water hydrology, presence of vegetation, and time of year.

Source reduction

The program will place emphasis on source reduction prior to a larvicide application to reduce overall pesticide usage in the environment. This will include, but is not limited to, vegetation management, ditch and catch basin cleaning, removal of water flow obstructions with land owner/management approval and the reduction or removal of mosquito habitats on residential property such as un-maintained swimming pools, birdbaths, old tires, buckets, and clogged

gutters.

Biological agents

Gambusia Affinis Washington County will distribute Gambusia affinis (Mosquito fish) to residents of the County for mosquito control in aquaria. Washington County enforces ORS 498.222, which allows Mosquito fish to be stocked only in aquaria; defined as self-contained systems that are not fed or drained by natural waterways such as ornamental ponds and stock troughs. ORS 498.222 states, “Natural wa terways include creeks, streams, sloughs, ponds, lakes, and ditches if connected to natural waterways.

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 8 of 13Bacillus thuringiensis var. israelensis (BTI) BTI (product name Vectobac G) has the capability to control a wide range of mosquito species with a very low impact on non-target species, making this larvicide an important product for tactical control of mosquitoes in Washington County. Bti can be applied to a wide range of water areas. Vectobac G will be used to control first through third instar of mosquito larvae.

Bacillus sphericus (BS) Bacillus sphericus (product name VectoLex CG) has the capability to control a wide range of mosquito species with the excepti on of Anopheles spp. VectoLex CG is well suited for wetland areas and waters with high organic content such as wastewater and dairy lagoons. This product has the ability to provide residual control of mosquito larvae up to four weeks. VectoLex CG will be used to control first through third instar larvae.

Methoprene Methoprene (product name Altosid) is an In sect Growth Regulator (IGR) that does not directly kill larvae mosquitoes, but disrupts the immature larvae stages preventing the larvae from developing into adult mosquitoes. Methoprene will be used in the form of Altosid primarily in catch basins, storm water facilities, ditches, and tires. In 2009, the County and IGA partners will begin treatment of public sumped catch basins in June to ensure control throughout the mosquito season.

Chemical Agents

Agnique or Golden Bear may be used if other products used were not effective and mosquitoes are in their pupae stage. The decision to use Agnique or Golden Bear will be made based on mosquito species and if the number of pupae present is greater than five (5) per dip.

Adult Control

To date, adulticide applications have not been conducted in Washington County. In the event of a public health emergency, adult mosquito control in the County will be based on cases of arbovirus illness detected in the County, vector mosquito abundance, environmental conditions and habitat, and the proximity of detected vector mosquitoes to more densely populated areas within the County. If an arbovirus is detect ed in the County, adult samples collected will indicate vector mosquito presence and density as well as infected mosquito presence to determine which areas have mosquito populations with an increased capacity to vector arbovirus in humans (if applicable).

Adult trapping will take place in selected areas before an adulticide treatment is applied. The mosquitoes trapped from the selected location will be placed in the targeted adulticiding area.The mosquitoes placed at the adulticide application area pre-treatment will be collected posttreatment to determine efficacy of the application. Pre and post-treatment trapping collection

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 9 of 13may be done to help determine if the adulticiding was effective, and to help eliminate skewed findings that could be caused by in-migration. Washington County will make every effort possibl e to minimize effects on non-target organisms using proper adulticide application techniques including rate, droplet size, and atmospheric conditions in accordance with label recommendations and published literature. Adulticide products will be applied using Ultra Low Volume applications. In the event that an arbovirus is detected in the County, contracted services will apply adulticide products to areas of concern. If West Nile Virus becomes a threat that surpasses the ability to control adult vector mosquito populations by ground using ULV applications with pickup trucks, then aerial applications may be considered. A contract is established with Adapco Mosquito Control for aerial applications.

(See attached 2009 Control Agent Worksheets.)

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 10 of 13PART VII: PUBLIC EDUCATION AND AWARENESS

Washington County provides bilingual education materials. Information will be provided to local schools, day cares, senior centers, hospitals, healthcare facilities, city resource centers, libraries, kennels, and feed stores through out 2009, as requested. The County has prepared brochures with information on West Nile Virus for public distribution. The County also provides information on the Washington County we bsite. Technical staff presentations and educational displays are available upon request by the County Environmental Health Program Educator and Mosquito Control Coordinator.

General Public Notification
3⁄4 Distribution of a West Nile Virus informational brochure and bookmark developed to educate the community on ways to reduce mosquito populations as well as to provide information on reducing the risk of mosquito bites. This brochure will be distributed to school districts, day care centers, senior centers, hospitals, health care facilities, city resource centers, libraries, and kennels as needed through out 2009.
3⁄4 General information is available on the Washington County website.

Multi-media Resources
3⁄4 West Nile Virus prevention and vector mosquito control information is available on the Washington County website to provide information to the public. Additional federal and state educational resources are provided as links at this site: http://www.co.washington.or.us/deptmts/hhs/env_hlth/vector/msqt_idx.htm
3⁄4 The Washington County Animal Shelter currently has mosquito control brochures available for customers and directs the community to our website for more information.
3⁄4 A bilingual (English/Spanish) press release regarding West Nile Virus and suggested measures to be taken by the public to reduce exposure to mosquito bites was created and released to local newspapers in 2008. This is projected to take place again in 2009. An information helpline is available in English and Spanish for the public regarding West Nile Virus year-round.

Presentations to Schools, Church Groups, Civic and County Organizations
3⁄4 The Environmental Health Program Educator and Mosquito Control Coordinator will be available to give presentations and for community events throughout the year.
3⁄4 Presentations on mosquito biology, prevention and control are advertised through the "Let's Talk about It" communications section on the County’s website.
3⁄4 The Environmental Health Division will host a booth at the 2009 Washington County Fair, which provides information and interactive games for West Nile Virus education. The booth will provide an avenue to target a large public sector which might not otherwise be reached. Other resources and the availability of Mosquito fish will also be highlighted.

Display Educational Materials at Events Display materials, brochures, and other educational resources are available for use year-round at community events, fairs, and presentations. An education wheel has shown to attract attention to Washington County's West Nile Virus booths while engaging the public.

Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 11 of 13Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 12 of 13Washington County Arbovirus Management Program, 2009 Pesticide Use Plan Page 13 of 13