# Best Management Practices for Mosquito Control

___________________________________________________ Washington State Department of Ecology Water Quality Program

May 2004 Publication 03-10-023 revised

# Best Management Practices for Mosquito Control

___________________________________________________ Washington State Department of Ecology Water Quality Program

May 2004 Publication 03-10-023 revised

### For additional copies of this document contact:

Department of Ecology Publications Distribution Center P.O. Box47600 Olympia, WA 98504-7600

Telephone: (360) 407-7472

Ad a m s

As o t i n Be n t o n Ch e l a n C l a lla m

Cl a r k C o lu m b ia

C o w lit z D oug l a s Fe r r y

Fr a n k l i n Ga rf i e l d Gr a n t Gra y s Ha r b o r Is l a n d

J e ffe r s o n

Ki n g K i t s a p

Ki t t i t a s

K l i cki t a t Le w i s c L i nc ol n

Ma s o n Oka n o g a n

Pa c i f i Pe n d O r e ille

Pie r c e Sa n J u a n
Sk a g it

S k am an i a Sp o k a n e St e v e n s

Th ur s t o n S n oh om i s h

Wa h k i W a lla W a lla Wh at c o m

Wh i t m a n

Ya k i m a a k u m 

### N o r t hw est 425- 649- 7000

S o ut hw est 360- 4 07- 6300 E ast er n 509- 329

- 3400 C ent r a l 509- 575- 2490 H eadqu ar t e r s ( L acey) 360- 407- 6000 I f

yo u a r e sp eec h o r h ear i ng i m pai r ed, cal l 711 o r 1- 800- 833- 6388 f o r T T Y

Re g i o n a l O

ffi c e l o cat i o n

S p ok an e

Ya k i m a La c e y B e lle v u e



### If you need this publication in an alternate form at, please contact us at360-407-6404. Call TTY (for the speech and hearing impai red) at 711 or 1-800-833-6388.

# Table of Contents

Table of Contents

................................................................................................................... i
Tables

............................................................................................................................... .... ii
Introduction ...........................................................................................................................1 Best Management Practices for Mosquito Control ................................................................3
I. Minimize Mosquito Bre eding Sites and Utilize Personal Protective Measures

.......... 3 II. Monitor Mosquito Populations and Disease

.............................................................. 6 III. Establish T a rgeted Densitie s for Mosquito Populations

........................................... 11 IV. Mosquito Control Treatments ................................................................................ 12 Appendix A: State List ed Species Restricted Areas

................................................................ A-1 Appendix B: Insect Repellant Use and Safety

.......................................................................... B-1 Appendix C: Response to Publlic Comments

........................................................................... C-1

Best Mana g e ment Practi ces for Mosq uito Control i Washington State Depar t ment of Eco l ogy

# Tables

Table 1. Disease Vector Mosquito Specie s Associated With Dr ainage Control Facilities

.... 9
Table 2. Potential Dis ease-Carryi ng Mosquit oes in Washington State

.................................. 10
Table 3. Permitted Insectici des Used For Mosquito Control

.................................................... 16
Table 4. Insecticides Used for Adult Mosquito Control

............................................................. 19

Page ii Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Introduction

On April 10, 200 2, th e Washington State Departm e nt of Ecology (Ecology) issued NPDES General Permit No. WAG-99200 0, covering mosq uito control ac tivities tha t disch a rge insecticides directly into surface waters of the stat e. Und e r the permit , the use of insecticides for mosquito control in water is allowed when t h e effects are temporary and confined to a specific location, though locations where insecticides are used may be wi de spread th roughout the stat e. Applications of insecticides are subject to complianc e with the Fe deral Insec t icide, Fungi c ide, and Rodenticide Act (FIFRA) labels, the Washington Pesticide Contro l Act (15.58 RCW) , the Washington Pesticide Application Act (17.21 R C W) , the General Pesticide Rules (WAC 16-228) , the Worker Protection Standard ( W AC 16-233 ) , a number of pesticide and/or county specific regulations
, mo nitoring/reporting req u irements , and appro v ed best ma nageme n t p r actices (BMPs) th at include integrated p e st manage m ent options. When ad opte d by a mosquito control entity, these BMPs for Mosq uito Control satisfy that NPD E S Permit No. 992 000, C o ndition S4 req u irement.

These Bes t Managemen t Practices for Mosquito Co ntrol were developed th rough a collaborative effort of representatives from Washington an d O r egon based mosq uito control districts, Washington State counties, Washing t on State Univer sity, mo squito contr o l insecticid e industry and the st ate de partments o f Health, Agriculture, Fishand Wildlife, Transportation and Ecology. Our appreciation goes out to the many mosquito contro l expe rts and others who took the time to revie w the draft and offer their expertise and suggestions.

Mosquito control entities in Washington State that wish to d e velop their own BMPS may do so, but they must b e approved by Ecology. An approva b le integrated pest ma na gement (I P M ) program for
mosq uitoes must involve natural resource scientis ts wh en pla nning control measures that could harm delicate ecosystem s and include all the fea t ur es of IPM as defined i nWashington State law RCW 17.15. 010 (a s ad apted to mosq uito manage m ent):

1) Minimize mosq uito br eeding and fee d ing sites. 2) Monitor mosq uito populations and disease. 3) Establish the targeted densities of mosqui to populations based on comm unity factors of health, public safety, eco n omic and a e sthetic thre sholds. 4) Treat mosquitoes to reduce populations belo w the targeted t h reshold using strategies t hat may include biological, cultural , mechanical, microbial, bioch e mical and chemical control methods and that consider human health, ecological impact , feasibility, and cost effectiveness. 5) Evaluate the effects and efficacy of pest treat m ents.

Best Mana g e ment Practi ces for Mosq uito Control Page 1 Washington State Depar t ment of Eco l ogyPage 2 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Best Management Practices for Mosquito Control

I. Minimize Mosquito Breeding Sites and U tilize Personal Protective Measures

Risk Assess ment: Probability of outbreak in humans: Remote
Action threshold : The p r esence or even the susp ected pres en ce of mosq uitoes (any species) in an area identified for control efforts tri ggers minimi zation eff o rts in the e a rly spring and summe r. The mean devel o pment time from egg hatch to pupation takes 5 to 10 da ys a ttemperatures near 25o C (77o F) (Pratt and Moore, 199 3). However, “eggs of certain species can hat ch in water as cold as 4 5 o F” ( Lilja, 200 2, p. 24) . Minimization a c tions are m o st effective in the early spring and continued through fall on an as-nee ded basis. Rationale: Minimizing man-made breeding sites in th e targ eted area of control and personal protection, especially for those with compromise d immune s y stems, are t h e best defe nses against getting bitte n by mosquitoes, giving th e best prot ection for the least cost.

Minimum BMP Respo n se: 1. Provide info rmation to those in the area of control on eliminating artifici ally created
mosq uito breeding sites, use of biological co ntrols (including bio-larvicides), use of repellents, a n d on prote c ting animals of concern. Local and s t ate e n viron m ental he alt h department s have a variety of informational brochures. See http://www.doh.wa.gov/ehp/ts/Zoo/WNV/ W NV.html for links.
2. Take appropriate minimization act i ons. 3. If possible, obtain resources to enabl e effective responses.



### Minimization Action s

Eliminate Artificial Bre e ding Sites around Homes and Offices

3⁄4 Empty or turn over anything tha t ho lds stand ing water—old tires, bucket s, wheelbarrows, plastic covers, and toys. Do not let w a ter stag nat e for more than s e ven d a ys. 3⁄4 Change w a t e r in birdbaths, fountain s, wading p o ols, and a n imal trough s weekly.
3⁄4 When practical, drill hol e s in the bottoms of containers that are left outdoors.
3⁄4 Clean and c h lorinate sw imming pools that are n o t in use an d be aware t hat mosq uitoes can breed in the water that collects on swimming pool cove rs. 3⁄4 Consider ae rating ornamental pools and use la ndscaping t o eliminate standing w a ter; mosq uitoes can potentia lly breed in any st agna n t puddle tha t lasts more than four da ys. 3⁄4 Recycle unused containe rs—bottles, cans, and buckets that may collect water.
3⁄4 Make sure roof gutters drain properly, and cl ean clogged gutters in the spring and f a ll.
3⁄4 Fix leaky outdoor faucets and sprinklers.
3⁄4 Keep all ornament a l shr u bs and bushes trimme d and pruned to open th em up to light and air flow. Thi s will not only give mosquitoes fewer places to hide, but will promote g r owth and vigor in the plant s.

Best Mana g e ment Practi ces for Mosq uito Control Page 3 Washington State Depar t ment of Eco l ogyUse Approp riate Bio-controls

3⁄4 Stock water gardens that have no surface inlet or o u tlet with mosq uito-eating fish ( i.e., goldfish, mud minnow, stickleback, and perch). Tadpol es, dragonfly larvae, divin gbeetles, back swimmers, and front s w immers also prey on mo squito la rvae. For more information, see http://ww w .wdfw.wa. g ov/factshts/westnilevirus.htm

. 3⁄4 Native vegetation and n e st box e s can help a ttrac t mosquito-e ating birds and bats. Ho wever, property ow ners should avoid introducing non-native fish or wildlife in a nattempt to control mosq uitoes. While it is permissible to release so me fi sh commonl y available in pet stores into s m all, contained backyard pools and ponds, non- native fish s h ould not be released into open or partially contained wate rs that m a y occasionally flood into nat ural water bodies. Some non

- native species, includin g so-called mosq uito fis h
, Gambusia affinis
, can be majo r pests whe nintroduced outside th eir natural range. Gambusia are aggressive and have be en known to feed on egg s , larvae an d juvenile native fish an d amphibians. Because of t h ese negative impacts on native species, Gambusia is a regulated species in Washington State, and may not be i n troduced without a fish stocking p e rmit issued by WDFW.
3⁄4 Under WDF W policy, transfer/stoc king permits may only be issued to organized mosq uito control districts, the U.S. Army Corps of Engi nee r s, and local or state hea l th departm e nts; permits ma y not be issued to private individu als. To protect the Olymp i c mud min n ow, a state sensiti v e species, Gambu s ia stocking is pr ohibited in Cl allam, Jefferson, Kitsap, Grays Harbor, Mason, Thurston, and porti o ns of Lewis County thatdrain into t h e Cheh alis river. For information on fish stocking permits cont actthe WDFW regional office in your area.
3⁄4 Selective b i o

- pesticides such as Bacillus thuringiensis isra elensi s (Bti), B. sphaericus or methoprene are very effective pree mptive contro ls when applied in the spring to specific sources identified by surveys. Amplifying and bridge vector species sho u ld be targeted (also see p. 11.).

Personal Protective Measures

3⁄4 Make sure window and door screens are "bugtight." Repair or replace if needed.
3⁄4 Stay indoors at daw nan d dusk whe nmosq uitoes are the mo st active.
3⁄4 Wear a long sleeve shirt, long pants and a hat w h en going in to mosq uito-infested are a s such as wetlands or woods.
3⁄4 Use mosq uito repellant when n e cess ary, and car e fully follow directions on the label

. For

ex tensive repellent information from the Ce nters for Disease Control see Appendix B: Insect Repellent Use and S a fet y 3⁄4 Areas frequented by the public, such as park s, zoos, outdoor concert are a s, and wildlife reserves should consider making repellents available.

Protect Animals of Concern

3⁄4 To protect your horses and other eq uines, ta lk t o your veterinarian about the West Nile vir u s vacc ine. The vaccine requi r es two doses t h ree to six weeks apart, a n d immunity may

Page 4 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogynot be achie v ed until up to six weeks after th e se cond dose. An annual booster should be given a few weeks to a month prior to the star t of the mosq uito season i nyour area. 3⁄4 Veterinarians should be consulted if you have concerns about your household pets or other animals. Re pellents ma y be used in some inst an ces. 3⁄4 Thoroughly clean livestock watering troughs weekly.
3⁄4 For more information see: http://www.aphis.usda.gov /lpa/issues/wnv/prv.html and/or http://www.cdc.gov/ncidod/dvbi d/westnile/birds &mammals.htm

New Con s truction and Storm Drains


### As new facilities are being designed, consideration shou ld be given to reducing mosquito habitat as much as possible.

When cons idering a drainage or water treatm ent facility for mosquito contro l, the first consideration should be whether the pr oblem could be reduced by physical modification or repair without co mpromi sing the facility’s function. Physical modifications should be designed by an engineer and reviewed by the local government to insure they meet applicable design requirements. A possible design modification may incl ude scarifying the p o nd bottom where it is no longer infiltrating as originall y designed, providing slope to the bottom of the drainage facility or enhancing infiltratio n by some other method. Elimina t ing low spots that collect small amounts of standing water and altering ex c e ssive overgrown vegetation ma y also be options. A l terations of slopes or repairs to a facility should not inv o lve a reduction in the water retention or carrying ca pacity of the facility. As an example, soil should not be added to fill low spots. Inste a d, low sp ots should be graded flat such that the carrying capacity is not reduced.

Sprinklers and Irrigatio n Systems

Over-watering and poor irrigati on practices are common producer s of mosq uitoes around the home, in parks, in irriga ted fields, and on golf courses. Report standing water to ap propriate maintena nce personnel.

3⁄4 Irrigated lands are amon g the high es t producer s of mosq uito breeding sites in Washi n gton State. High numbers of mosq uitoes can deve lop in standing water as a result of flood irr i gation. The actions b e low can hel p elimi nate mosq uito breeding sites by using physical controls (Colorado, 2002 ; Pratt a n d Moore 1993)

. 

### 1) Minimize standing wat e r in fields so that it do es not lie fallow for more than four days by improving drain a ge chan nels and gradin g. 

### 2) Tail waters s h ould not be allowed to accumu late for more than four days at the end of the field. 

### 3) Keep excessive overgrown vegetati on ou t of ditches to promote more rapid drainage, but retain ground cover to prevent soil loss.

Best Mana g e ment Practi ces for Mosq uito Control Page 5 Washington State Depar t ment of Eco l ogy

### 4) Have ditches repaired to reduce seepage to t h e extent practicable (elevated water tables can p r oduce unintended s t an ding water in fields). Modification o r repairs to a ditch should not reduce the carrying capacity. 

### 5) Minimize fl ood and rill irr i gation pr ac tices to the extent practicable. 

### 6) Avoid over-watering.

Foster Healthy Wetland s

Do NOT drain or fill wet l ands. The c hance of mo squito "o utbreaks" increases in wetl and and
stream ecos ystems that have been changed or t a mper ed with. In disturbed systems
, the predat ors of mosq uito larvae are often ex cluded while the mosq uitoes thrive. Thus, draining wetlands an d removing gr eenbelts will not eliminate mosquito es. Infact, such actions could act u al ly increase the mosquito po pulation if t h eir natur al predators are destroyed. Th e draining of wetlands will still leave behind many s m a ll puddles or wet depressi ons tha t ar e prime habitat for mosq uitoes.

Wetlands pe rform at leas t three class e s of functions: hydrologic function s ( i.e ., flood peak reduction, shoreline sta b ilization, or groundwater ex change), water q u ality improvement (s ediment accretion, filtration or nutrient uptake), an d fo od-chain su pport (struct u ral and species diversit y components of habitat fo r plants and animals, including threat ened end a ngered and sensitive species). Many wetlands re charge ground water critical for local drinking water supplies and prevent stream s from drying up during the summer. Given the critic al functions wetlands perf orm, Ecolog y does not condone draining wetlan ds as a met h od for mosquito control. Since most predation on mosq uitoes occurs when they are lar v ae, the bestmosquito co ntrol is often to targe t the larvae, e i ther by fostering predators na tive to the are a of contro l (amphibian larvae, aq ua tic salaman d ers, small f i sh) or by applyi ng selective larvi c ides such as Bti. (T om Hruby, Ecology We tland Specialist, personal communication 2/26/0 3 and 1/ 16/0 4 ).

II. Monitor Mosquito Populations and Disease

Risk Assess ment: Probability of outbreak in humans: Re mote to low; ar eas with limited or sporadic WNV epizootic activity in birds and/or mosq uitoes. Action Thre shold. The presence of vector or nuisance mo sq uitoes suspected or confirmed in the

area. Rationale. Base-line data on mosquito populati ons and mosquito- b orn e disease will help target educational efforts and a r e essential t o control efforts, should they become necessary. Minimum BMP Respo n se. Obtain and track a v ian mortality, human e n cephalitis/meningitis, and equine surveillance in the area of co ntrol. Fu rther q u antify epizootic activity by in ventorying mosq uito habitats, and t r apping and testing for ve ctor mosquitoes. Consi d er targeted insecticide control if survei llance indicates high potential for human risk to increase

. Monitoring Strategies for Landowners of Private Property and Contracted Licensed Applicators

3⁄4 Contact your local health departme nt for in formation about birds, horses, and hum ans found to test positive for West Nile virus or other mosq uito-borne diseases in your a r ea of control.

Page 6 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy3⁄4 Accurately map and ide n tify rearing areas for m o squitoes, by species if possible. These are those site s f o r mosq uito rearing thatcannot be el iminated by following preventative measures such as contai ner emptyin g , proper pond mainte n ance, and eliminating ex cess standing w a ter by using appropriate irriga tion BMPs. This is important because appropriate treatmentm e asures are contingento nthe habitat(species) encountered.

The following northwes t mosq uito habitats a n d control issues have bee nidentified in the Mosq uito-Borne Response Plan d e veloped by the De partmen t of Health ( L ilja, 2002)

. Vectors in specific regions have no t all been identified. Co nt act your local health department for the latest
mosq uito vector informa t ion.

Floodwater.: Aedes vexans and Ochlerotatus sticticus develop in large numbers along the borders of the Columbia and ot her rivers and create importa n t mosquito problems in this region. The larvae hatch in the spring or early summer when th e str e ams overflow areas su ch as willow and cottonwood swales where the egg s have been laid . The eggs of these spe c ies are dormant w h en temperatures remain below 45-50oF. Partial dorm ancy of the eggs may continue until sometime in June so that only some o f the egg s ar e hatched b y floods occ u rr ing in Ap ril or May. In some seasons, the larger ri vers may rise, recede, and ri se again to co ver the same egg beds and produce an addition al hatch. In other seaso n s, two or th r ee successive rises may occur, each of which is higher than the last. Females th at emerge in the first hatch may lay eggs that will hatch in the second or th ird rises of the river. Most of the eg gs are laid between the 1 0 and 20 foo t levels, and some of the eggs th at ar e not floode d during a seri es of low flood crest years remain viable fo r as long as four years.

Large Aedes vexans and Ochlerotatu s sticticus breeding areas have been managed efficiently by controlling water levels above dams such as the Bo nneville Dam. Dikes have prevented flooding in other areas. Clearing of brush has been of value in some locations. However, contr o l of the major section of these types of breeding areas must ofte n be accomplished with insecticide applications.

Irrigation Water: Breeding places for several mosq uito spec ies are provided by i rri gation water. Aedes dor sali s , A. vexans, Ochlerotatu s melani mon , and Ochlerota t us nigromac ulis are amo n g the most important s p ecies that may develop when wa t e r is applied and st ands for a week o r ten days. Other species such as Culex tarsalis, C u liseta inorn ata, and Anopheles freebo r ni may also be produced. Tremendous numbers of mosquitoe s breed in many area s w h ere uncontrolled irriga tion is practiced. Appl ication s of insecticides are effe c t ive but are not substitute s for proper grading. Elimination of standing water is effective in pre v en ting development of mosquitoes. Application of insecticides may be necessary for breeding places that ca nnot be drained. See Sprinklers and Irrigation Systems in Sec t ion I above.

Tidal Waters: Aedes dors alis is the only species that can breed in large numbers in both fresh and salt water in the Northwest. Th e larvae develop in some coastal areas where potholes are filled by the higher ti des or wher e water levels fluct u ate inpermanen t or semi-permanent po ols. Leveling, drainage, or similar practices are effe ctive in pre v enting breeding, but such areas mu st be properly maintained. Insecticide control may be nece ssary where the s e methods are inadequate or ineffective. Ochlerotatu s togoi has als o been found in coastal areas including San Juan, Island,

Best Mana g e ment Practi ces for Mosq uito Control Page 7 Washington State Depar t ment of Eco l ogySkagit, Kitsa p , and Maso n counties. Larvae of th is species have been found in pools of pure
seawat er along rocky shorelines.

Snow Water: In ma ny high mountain meadow s and also atlower levels , mosq uitoes breed in pools caused by snow melt. Development may req u ire several weeks at hig h er elevations. Aedes communis, A. cinereus, Oc hlerotatus he xodontus, O. fitchii , and O

. increpitus a r e the most common species found in these locations. Usually there is only one generation per year, but the large numbers tha t may be produced are a severe annoyance to those who are working or seeking recreation in these areas. Elimination of breed ing areas by d r ainage or maintena nce of constan t water levels is practical i nsome situations. Inse ct icide applications mighthave to be made by ha nd or by plane because of inaccessibilit y to heavy ground equip m ent.

Permanent Waters, Ponds and Artificial Containers: The mosquitoes that lay their eggs on the water are usually found where water is present c o ntinuously during the season or at least for several days. Such locati ons include natural pe rmanent ponds, includin g still waters along the borders of la kes and rive rs sheltered from wa ve action and currents with s o me degree of vegetation, log ponds, tr ee holes, se mi-permane nt ponds an d wetlands of various types, and artificial containers . Culex tarsali s , C. pipiens, C. peus, Anophel es freeb orni, A. punctipennis, Culiseta incidens, and C. inornata are commonly found in such places. C. tarsali s and C. pipiens develop in large numbers in log ponds . C. pipiens also develops in large numbers in sewer drains, catch basi ns, and wat e r left in artificia l containers. Coquillettidia perturbans are found in permanent water in wetlands, s w amps, a n d marshes th at have em e r gent or floating vegetati on. Insecticides are ofte n used effectively to control most of these species, ex cept those breeding in artificial containers th at can be empt ied. Larvae of C. perturbans are difficult to control because they are att a ched to the roots of plants. Insecticide granules are someti mes applied, but eliminating host plants may be the most useful procedure to control this species. C o nsult with your local WDFW office before removing plants o nWDFW-manage d lands or in ecologically sensitive areas.



### Stormw ater: In response to the anticipa ted arrival of W e st Nile vi rus in King County, King County Water and L a nd Resources developed recomm endations for dealing with the m o squito control at County drainage facilities. The study (W hitworth, 2002) identified the four ba sic habitats preferred by m o squitoes, the types of m o squitoes associat ed with the habitat type, and the W N V vector mosquito sp ecies that p r efers each h abitat type . Table 1 summ arizes this inform ation.

Page 8 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

### Table 1. Disease Vector Mosquito S p ecies A sso ciated W ith Drainage Co ntrol Facilities
H a b i tat Ty p e F a c ility ty p e Vec t o

r S

p

ec i e

s

P e r m ane ntW a t e r Y ear ro u nd w e t pon ds L a r g e r R egi o nal Po nds We tB i o s w a l e s An oph el es

pu nc t i pen ni s

M a rs hes & W e t l and s W etB i os w a l e s S o m eR e g i o n a l F a c ilitie s A e d e

s c

i ne r e us C

o qui l l et

i d

i a p e r t u

r ba ns

Te m p o r ar y or

Fl o o d W a t e r T e m po r a r y W e t P o nd s Dr

y B i o s w a l e s R e t e nt i o n/ D e t e nt i o n P o n d s O pen D i t c he s Ae des v

e x

ans C

u

lis e t a in or na ta

A r

t i f i c i al C o n t ai n e rs / T r ee H o l e s C at c h Ba s i n s U nde r g ro und Ta nks / Va ul t s D i sca rd e d co n t a i n e rs & T i r e s Oc hl

er

ot

a t

us

j

apo ni

c u

s C

u

l e x pi

pi

ens C

u

le

x ta r s a lis C

u

lis e t a in or na ta

Table 2 summarizes biological inform ation of v ector m o squitoes foundin Wash ington State.

Best Mana g e ment Practi ces for Mosq uito Control Page 9 Washington State Depar t ment of Eco l ogyTable 2. Potential Disea s e-Carrying Mosquitoes in Washingt on State

M o s qui t o Spe c ie s Da y or Ni ght Bi t e r Ra nge G e ne r a t i on s pe r Y e a r Pr e f e r r e d Ha bi t a t B r e e d i ng Com m e nt s

Ae d e s
c ine r e us A g gr ess iv e du r i n g da y D o e s n o t tr a v e l f a r fr o m ha bi t a t O n e- eg gs ha t c h at di f f er en t ti m e s A wo od l a n d spe c i e s: se m i

pe r m an en t b o g s & swam ps,

w e tl a n d s , w e t b i o s w a l e s & f l oo dwa t er s H a tc h e s i n th e e a r l y spr i ng

. L a r v ae f o un d

am on g d e n s e aq ua t i c

v e g e ta ti o n

.

A e d e s ve xa n s Da y & N i gh t 2 0+ m i l e s M a n y A n y t e m p orary wa t e r bo dy l i k e di t c h e s , pu dd l e s , c o nt ai ne r s , p o o l s & f l oo dwa t er

. E g g s m a y l i e do m a nt 3+ y r s , ha t c he s i n di t c h e s , s t ill w a t e r

.

A nophe le s pu nc t i pe nni s Ni g h t S t ay s ne ar ha bi t a t

. On e S p ri ng s an d c r e e k s
c o nn ec t e d t o s t o r m w at e r po nd s, b i oswa l e s a n d

we t l an ds

. P r ef e r s al g a e

- l a de n, coo l p o o l s on ed ge s o f s l ow fl o w i n g r i ve r s an d st r e am s. H a s e n t i r e l y d a r k p a lp i.

C oquil le ti d i a pe r t ur ba ns Ni g h t - of t e n
com e s to l i g h t s St r o n g f lie r s , en t e r s ho m e s
an d l i t

ar ea s. O n e, bu t ha t c h l i n gs do

no t co m p l e t e de v e l o pm en t

un t i l t h e fol l owi n g spr i ng

. P e r m an en t m a r s h e s,
we t l an ds

, t e m p orary wet p o n d s , dry bi os wa l e s & op en d i t c he s. N e ed s t h i c k gr o w t h of aq ua t i c v e ge t a t i o n

. R e m a i n s be l o w t h e wat e r
sur f ace a t t a che d t o r o ot s
an d st em s. H a t c hl i n g s
em er ge i n spr i ng

.

C u le x pi pie n s Ni g h t Us u a l l y
m i grat es
on l y sh or t di st a n ce s. M a n y F o un d a r ou nd wat e r w i t h hi g h o r ga ni c co nt e n t
, a s i n cat c h b a si n s & sewer ef f u e n t po nd s, t r ee h o l e s,
ar t i f i ci al co nt ai n e r s &

m a nh ol e s

. P r o lif e r a t e in in a r t i f i c i a l

c o nt a i ne r s

. L a y s eg gs i n cl u s t e r s of 5 0 t o 40 0. La r v a l an d pu pa l st a g e s t a k e 8 - 1 0 da y s

.

C u le x t

a r s a lis Ni g h t En t e r s bu i l d i ng s
a f t e r d a rk

. M a n y A n y f r e s h wa t e r , ar t i f i ci al

c o nt ai ne r s , & ag r i c u l t ural

an d i r r i ga t e d a r e a s La r v a e de v e l o p f r o m
s p r i n g to f a l l i n w a te r s w / h i g h orga ni c m a t e ri al

. E g gs l a i d i n r a f t s of 10 0 - 15 0 & h a t c h w/ i n 48 h r s.

Cu l i s e t a inor na t a Da w n & Du s k S t ay s ne ar ha bi t a t

. M a n y C o l d wat e r - asso ci at e d wi t h gl a c i a l r u n o f f an d sun l i t

w a te r s , d o e s n o t l i k e h o t

wea t h e r

. F o un d at al l el e v at i o ns. B r e e d s t h r o ug ho ut s p r i ng
an d su m m er i n col d

w a te r , f e m a l e s m a y ap pe ar d u r i ng war m wi n t e r br ea k s

. U s ua l l y fe ed s on l i v e s t oc k

, no t pe op l e

.

O c hle r ot a t us j a poni c u s Da y & N i g h t N ot k n own M an y A r t i f i ci al co nt ai n e r s , ca t c h ba si ns, un de r g ou nd t a nk s
an d v a u l t s & t r ee ho l e s La r v a e ar e f o u n d i n
ar t i f i cal co nt ai n e r s

. *Ne w i n f o rm ati on has com e i n on Oc hl er ot

a t us c a n a densi s th at adu lts liv e for sev e ral m o n th s in wo od lan dpoo ls b y melt in g sno w o r rain. Th ey feed o n a larg e rang e o f m a mmals, b i rds, and rep tiles.

Page 1 0 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyAdditional Monitoring for Public and Specialty Targeted Areas of Co ntrol

3⁄4 Conduct ongoing mosquito lar v ae sur v eillance, including studying habitats by air, a e rial photographs and topog r aphic maps, and evalua ting larval populations.
3⁄4 Monitor and track data f r om mosquito traps, bi ting counts, complaints, and reports from the pub lic.
3⁄4 Keep seaso n al records concurrent with weat he r d a ta to predict mosq uito larval occurrence and adult flights.
3⁄4 Consider using sentinel chicken floc ks for su rveillance (See Centers for Disease Control and Prevention, Epidemic/E pizootic We st Nile Vi r u s in the United States: Guidelines for Surveillance, Prev ention and Contro l, page 10, http://www.cdc.gov/ncidod/dvbid/westn ile/resources/wnv-guidelines-aug-2003.pdf )
3⁄4 Accurately map and ide n tify rearing areas for mosquitoes. These would be those site s that cannot be eliminated by preventative measures such as emp t ying containers, proper pond maintena nce, and eliminating ex ces s sta n ding water by using appropri ate irrigation BMPs. These habitats can be identified by aerial ph oto assessments, topographic maps, and satellite imagery where available

. This is importantbecause appropriate treatme n t measures are contingent on the partic ular species that live in specific habit ats. 3⁄4 Agri cultural site maps should incl ude hay, pa sture, ci rcle i r rigation, orc hards, and rill irrigated field crops. An important land use th athas caused problems to mosq uito control districts in the past is flood irrigated pastur es wh ere the wa te r stays on m o re than five to seven days.

Note: Detai l ed information on mosquito surv eillance is available from Washington State Departmentof Health, a v ailable online at www.doh.w a .gov/ehp/ts/Zoo/WN V/WAArboviralRespPlan.pdf and http://www.doh.wa.g o v/ehp/ts/Z oo/WNV/ WestNileVirusSurv.pdf

III. Establish T a rgeted Densities for Mosquito Populations

Risk Assess ment: Probability of outbreak in humans: Remo te to low; ar eas with confirmation of epizootic W N V in bi rds before A u gu st; a horse/hu man case, or sustaine d WNV activity in birds and/or mos q uitoes. Action threshold: The p r esence (positive identification) of any vector mosquitoes in the area triggers activities to reduce their pre s ence. Since people with compromis e d immune systems are likely to be the most vulnerable to mosq uito-borne diseases, the areas of thei r exposu re should be a priority. Rationale: Once vector mosquitoes have been p o sitively ide n tified in an area, contro l treatments
are warrant ed, especially around highrisk populations. If t h e costof tr eatments is prohib itive, every effort should be made to educate tho s e at risk of exposure abou t minimizing habitat and personal protection me asures. BMP Minimum Response: Analyz e disease act i vity data, i.e. , avian mortality, human encephalitis/meningitis, equine en cephalitis and mosq uito surveillance information in the area of control. Set targeted densities with special consideration being given for segmen ts of the

Best Mana g e ment Practi ces for Mosq uito Control Page 1 1 Washington State Depar t ment of Eco l ogypopulation most vulner able to mo s q uito-borne diseases such as t h e elde rly. If neede d , enhance human surveillance and activities to further quantify epizootic activity, s u ch as mosq uito trappin g and te sting.

Establish Targeted Mosquito Densities for All Areas of Co ntrol

To establish the target ed density of mo squito po p u lations revi ew information on incidences of avian mortality, human encephalitis/meningitis, and eq uine encephalitis for your area (the Department of Health or your local h e alth depa rt ment can pr ovide this information). Conduct entomologic survey (inventory habitats a n d ma p mosq uito populations). Using surveillance information and input from the people in the co ntrol area, est a blish the targeted densi t y of
mosq uito populations based on t h e level of contro l desired by those in the area of control, pub lic safety, and f u nding.

3⁄4 Demarcate no-spray zo nes on maps . This may i n clude areas such as sch o ols, hospita l s, fish farms, wildlife refuges, ecological ly sensitiv e areas, th e home s of individuals who are on chemically sensitive registers, and crops grow n under a certified organic program. Other crop sites that do not ha ve a tolerance for the mosquito c o ntrol prod ucts used should also be listed. If th e control entity is not a m o sq uito control district organized under RCW 17.28, then individual residences where t h e occup ants do not want t o be treated should be identified as no-spray zo nes. 3⁄4 Individual h o meowners and busines s es det e rm ine targeted mosquito po pulation densities based on the level of con t rol desired and factor s of risk and cost. Mosq uito control agents must consult with their sponsors to determine t a rgeted mosquito densities.
3⁄4 Once the t a rgeted density has bee ne s tablishe d, continue larvae surveys to find densit y response to habitat mini mization eff o rts and ne e d for larvicide treatme n ts.

IV. Mosquito Control Tre a tments

Risk Assess ment: Probability of outbreak in humans: Low to moderate
Action Thre shold: The positive ide n tification of vector mosquitoes in the area may t r igger activities to reduce their presen ce. Once minimization strat e gies have b een tak e n, la rvae surveys ( i.e. dipping) can indicate the effecti v eness of those efforts and the need for further a c tion. General Permit Condition S4.2. C state s th atthe t a rgeted density of l a rvae is 1 pe r three dips to commence larvi c iding unless vector mosquitoe s are in the area and t h e probable breeding sites are inaccessible. This level is a minimum; mosq uito control agent s may w ant to set t h e t a rgeted den s ity at a higher level due to cost and risk factors.
Rationale: Once vector mosquitoes have been p o sitively ide n tified in an area, contro l treatments
are warrant ed. If t h e cost of treatme n ts is prohibit ive, every effort should be made t o educate those at risk of ex posure about minimizing breedin g habitat and personal protection me asures. Minimum BMP Respo n se: Treat mosquitoes to reduce populations below the t a rgeted threshol d using strate gies thatconsider bi ological, cultural, mec hanical, and microbial, biochem i cal, chemical control methods. Evaluate met h ods for effectiv eness of contr o l, human h e alth and ecological impacts, feasibil ity, and cost effectiveness.

Page 1 2 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

### Use an Integrated Pest Management (IPM ) Approach for All Areas of Control

Ideally, an IPM progra m considers all available cont rol actions, including no action, and evaluates the interacti o n among v a rious control practices, cult ural pra c tices, weat her, and habitat structure. An ecologic ally-based IPM strategy relies heavil y on natural mortality factors and se eks out control tactics that are compatible with or disrupts thes e f a ctors as litt l e as possible. When biological, biochemical or chemical treatment is needed, sele ct treatment s based on t h e species of mosq uitoes found in larva pools, the age of larva, breed ing habitat, density of larval populations and temperature.

Pesticide applications shall not commence unless surveillance of a poten t ial application site indicates a l a rva/pupa count of greater than 1 pe r 3 dips and the ne ed to apply insecticides to control mosq uito populations, or unless dead bird s, infected horses, or a d ult mosq uito surveys indicate the presence of vector mosquitoes wh en larvae coun ts cannotbe made due to their inaccessibili ty. In these cases beginning control methods such as larvicid ing may be desirable or even necessary without the larvae dips. However, just because a de ad bird is found which tests positive for WNV in an area does not mean tha t t h e vector mosquitoes are breeding in the nearest storm drain. Those in the business of controllin g mosquitoes will have to know the br eeding sites and species of vectors in the area to perform effective mosquito control.

Natural resources bi ologists (e.g., W D FW) must be notified of planned control measures wheneve r delicate (easily impacted ) ecosystems could be harmed by mosq uito control practices. Other resource manageme n t a g encies (e.g.
, National Mari ne Fisheries Service and U.S. Fish and Wildlife Service) should be cons ulted to dete rmine when and wh ere operations may harm e c osystems critical to threatened or endangered species, as we ll as appropriate treatments in the s e situations.

Biological Controls

Natural Waters: WDFW has several concerns with stocki ng biological m o sq uito predators in natural wat e rs. Along with the intr oduction of no n-native f i sh, the tran sfer of fish d i seases from one location to anot h er, even among native populati ons, can cause dise ase outbreaks. Thatis why all movement and stock i ng of fish req u ires a pe rmit from WDFW, whet her the fish are native or not. Due to the inability to test live fish withou t killing them, the transporta tion of fish from one watershed t o another re q u ires disease tes t ing (usually on the adults at s p awning, or by sacrificing a number of young fish) and verificati on thatthe r e maining fish are reared on disease-f r ee water. I n addition, any non-na tive fish stocking currently needs to go through SEPA review pr ior to approval. The laws in Washington State are d e sign ed specifically to pre v ent this type of “Johnny Apple-seeding” from occurring. For more informat ion, plea se contact y o ur nearest Regional Office of the Depar t ment of Fish and Wildlife.

Ponds or Im poundments with No Inlets or Outlets: Biological methods may include stocking species such as the Thre e-Spined Stickleback ( G a stero ste rous a c uleatus ) which is native to Washington State a n d k n own to be an effective predator of mosq uitoes. Mud minnow, perch tadpoles, dragonfly larvae, diving beetles, back swimmers a n d front swi mmers also prey on mosquito la rvae. Guppies, goldfish, and other fish commonly sold in pet stores are exempt from permitting by Washington’s Department of Fishand Wildlif e (WDFW) and may be suitable for smaller ponds with no i n let or outlet, horse trou ghs, a n d orn a ment al pools. However, before

Best Mana g e ment Practi ces for Mosq uito Control Page 1 3 Washington State Depar t ment of Eco l ogyplanting any of these ex empt fish, c o nsult with WD FW. Some of these fish, such as goldfish, may have severe ecological impacts on p o nds and la kes.

Mosquito Fish ( Gambusia affinis ) have been used for mosquito co ntrol in virtually every state because of the adult’s ability to con s ume large amou nts of mosquito la rvae. These warm water fish rarely ex ceed 2.5 inche s and prefer s hallow wa ter. They tend to flourish in almost any environment, including well discharges, cisterns, water tanks, potholes, r a in barrels, and open septic tanks. Gambusi a have been kn own to dra m atically re duce and even eliminate mosq uito larvae. WDFW suggests tha t the use of Gambusi a be integrated into an overall mosquito control plan rather t han used as an ex clusive solution to mosq uito abatemen t. P e rmits must be obtained from WDFW for use of Gambusi a as a mosq uito control measure.

Microbial, Biochemical and Conventional Chemical Controls

Appl ication s of insecticides to water must be ma de by individuals licensed by the W a shington State Department of Agric u lt ure and permitted by the Department of Ecology's Water Quality Program. Information on WSDA li cense requir ements is online at: http: //pep.wsu.edu or call WSDA toll- f r ee at (87 7 ) 30 1- 4555 . Permit ting information is available from Ecology's website at www.ecy.w a .gov/programs/wq/pesticides/index.html or call (800) 9 17- 0043

. Select product controls b y comparing the species and t a rget ed life stage of mosquitoes, the breeding habitat, den s ity of larval populations, and t e mpe r at ure with the efficacy of the products, nontarget impacts, resistance m ana gement, and costs. For e x ample, while Bacillus products are effective on early instars they do not control olde r larva. Methoprene can be used on older larval stages (i.e., pupa), and for situations where it is t oo late to use either Bacillus thuringiensis isra elens i s or Bacillus sphaericus , a monomolecular film might be used. Some Bacill us products do not have residual characteristics when t e m p eratures ar e high, a n d larval populations can g r ow at the r a te of an instar a day. In t h is situation t h e larva ma y be in the l a te third to f o urth instar stage before an application of Bacillus can be made. Always consult product labels fo r specific infor m ation on efficacy and use. Product Mat e rial Safety Data She e ts (MSDS) prov ide additional informat ion such as protocols or
measures to be taken for accidental releases and other pertinent product information.

The followi ng is the approved l i st of larvi c ides that m a y be considered for mosq uito control operations. Consult with federal, st ate and local agencies as needed.

1. Bacillus thuringiensis israelensis (Bti)
2. Bacillus sphaericus (H-5a5b)
3. Methoprene Granular, Liquid, Pellet, or Bri q uet (Restricted on state listed species site s

– see Ap pendix A).
4. Monomolec u lar S u rface Films (Restricted on stat e listed species sites

– see Appendix A).
5. Paraffinic white mineral oil. Paraffinic whit e mineral oil is r e stricted on state listed species sites

– see Appendix A and shall not be used in wat e rs of the state unless: a. The mosq uito problem is decl ared a public health risk; or

Page 1 4 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyb. The other control agents would be or are known to be ineff e ctive at a s p ecific
treatmentsite; and
c. The water body is non -fish-bearing (when unc e rtain, cons ult Washington State Fish and Wildlife concerning fish and wil d life) and has no inlet or outlet.
6. Temephos may not be used in lakes, stream s, wetlands or the littoral z o ne of water bodies. The use of teme phos shall be allowe d only in highly-poll u ted water (i.e. ti re piles) or waters with hig h organic conten t (i.e. m anure holding ponds a n d pastures with no surface water runoff), or under either of the two foll owing conditions:

a. As a result of consultation between t h e Departments of Agricult ure and of Ecology in response to the devel o pment of p e stic ide resistance or ineffectiveness within a population of mosquito es. When temephos is a pplied to areas draining to surface waters moni toring of persistence and resi dues are a condition of the approval. Temephos must be rotated with one or mo re of the approved alternatives with a different mode of action to minimi ze the development of resi stance.
b. As a result of consultation between t h e Departm e nt of Healt h and D e partment of Ecology in response to the developm ent of a h u man healthemergency as determined by the Washington State Departmentof Health.


### 7. Terrestrially applied insecticides are NO T regulated under federal or state water poll ution co ntrol laws and are not subject to NPDES permit conditions or requirements. A variety of adulticide s are regulated for use by WSDA in Washington State. Table 4 lists some of these products. How e ver, in Washington State all applications of insecticides over wat er must be permit ted under a Clean Wate r A c t (NPDES) permit.

Best Mana g e ment Practi ces for Mosq uito Control Page 1 5 Washington State Depar t ment of Eco l ogy

### Table 3. Per m itted Insec tic ides UsedFor Mosquito Larvae C ontrol

Ty pic a l P roduc ts Ac t i ve Ingre d ie nt La be l Us e Ra te a nd 200 3 co st estimat es A p plic a t ion M e thod(s ) Pe rs is te nc e and Comments Human Health Restri ctio n s Permit Restri ctio n s on Use ** Ta rge t Pests o n La be l

Aqua bac, Bactimos, Vectobac a nd T e knar ( Bti ) Bacillus thurin gie n sis israelens is 0.25 to 2 pints/acre or up to 10 lbs/acre @ $24/g a l.
Granul es $1.65/l b Han d spra yer, grou nd spray e r or spr i nkler

cans. Effective 1 - 30 da ys dep en din g on formulation. Broad sp ectru m , exce pt Coq u il letid i a Not for potab le

wa t e r

. Minima l no ndietar y a nd dermal risk to infants an d childr en. N o n e

. M o s q u i t o larva e

VectoLe x WDG Bacill us spha ericus (H-5a5 b) 0.5 to 1.5 lbs/acre $4.65/l b Granul es are mixed w i t h

w a t e r an d spra ye d. Effective for 1-4 w e eks, dep en din g on t he speci e s of mosquito larvae, w e ather, w a ter qua lit y an d e x a c t form of the gran ules

. Effective on Culex spp

. Less effective aga inst other spec ies. Not for potab le

wa t e r

. Essentia ll y nonto x ic to huma n s. Non e

. L a r v a l control i n
wa t e rw i t h hig h orga nic content.

Altosid l i qu id Methopr en e: A ctive ingr edi ent is a gro w th hormo ne mimic that does n o t allo w t he mosquito larvae to mature. 3-4 oz./acre $22 6/ga l

Altosid p e ll ets Methopr en e 2.5-10 lbs/acre $24/l b

Altosid X R Methopr en e 1 briq uette $2.70 @ 1 00 -2 00 sq ft.

Altosid briq uet Methopr en e 1 briq uette / $.90 @1 00 sq ft.

Altosid X R -G Methopr en e 5-20 l b s/ac $8.48/l b Use ha nd a nd grou nd spray e rs. Effective for a fe w da ys unl ess speci a ll y formulated for slo w rele ase. It is not persistent beca u se it de g r ades rapi dl y in w a t e r

. T he briquettes are use d in are a s ne ede d for lon ger term res i du al control suc h as pond ed areas of stan di ng w a ter,
areas w h ere fl ood

w a t e rs may m a ke it impossi bl e to use Bti.

Rates incr ease w i th dee per w a t e r.

Altosid XR-G is a sand formulati on, go od for pastures or ma rshes

w i t h thick vegetation. Not for potab le

w a t e r. Does not pose risks to huma n hea lth. Restricted on state listed sp e c ie sites – see Appe ndi x A. mosquito larva e .***

Page 1 6 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyTy pic a l P roduc ts Ac t i ve Ingre d ie nt La be l Us e Ra te a nd 200 3 co st estimat es A p plic a t ion M e thod(s ) Pe rs is te nc e and Comments Human Health Restri ctio n s Permit Restri ctio n s on Use ** Ta rge t Pests o n La be l

Agni que MMF
Arosurf MSF Monom olec ul ar surface film Poly(oxy- 1,2- ethan ed iyl)Alphaisoocta decylhydroxy 0.2 to 1.0 gal/acr e @ $30/g a l. Spra ye d b y ha nd or grou nd e qui pm ent. F ilm remains active for 10-14 da ys on flo o d w aters, brackis h w a ter s and pon ds. Suscep t ible to

w i nd break in g surface tensio n. Ren d e r ed ineffective at w i nds abov e 10 mp h and i n very choppy water. Adult femal e s are kill ed b y

entrap p i ng and d r o w ni ng w h e n th ey contact the sur f ace to la y t heir e ggs. Okay for potab le

wa t e r , livestock, back y ar d pon ds, poo l

covers. No risk to huma n hea lth. Restricted on state listed sp e c ie sites – see Appe ndi x A. Larva l, pup al and mid ge control.
Adult female mosqu i toes.

Golden Bear Oil Boni de Oil Petroleum distill ate oi ls preve n t the larvae from obtai nin g
o x y gen throug h the surface film 3 to 5 gal/acr e $5 -8/ga l Liq u id formu lati ons are spra ye d b y ha nd or grou nd e qui pm ent. Persists for 12 – 15 hours, then ev apor ates.
Less e x p ens e- -kills pup ae stag es No risk to huma n hea lth. Ma y n o t be app lie d to fishbear ing w a t e rs or on state liste d speci e sites – see Appe ndi x A. Larva l and pup al control.

Abate temeph os 0.5 to 1.5 oz/acre $2.00/oz Spra ye d liq ui d. Breaks do w n w i thi n a fe w da ys in stand in g w a t e r, sh a l lo w po nd s,
s w a m ps, mars hes, and intertid al zon e s

. T e mephos is a ppli ed most commonlyby helic opter b u t can be app lie d b ybac kpack spray e rs, fixed- w i ng aircraft, and right-of- w a y spra yers i n eith er liq uid or gran ular for m

. Not for potab le

wa t e r

. Poses lo w risk to human hea lth. Hig h dosa ges, lik e other OPs*,

can overstimulate the

nervo us sy s t e m , causi ng
naus ea, dizziness, & confusi on. Highly r e stricted

use – see per mit cond ition 1A.5. Mosquito larva e , midg e, punk ie g nat, and sa ndfl y larva e in

non- pota b le

wa t e r

.

Malath ion 8EC malath ion 8 oz/acre, cost NA Lab ele d for us e in intermittent flo ode d areas, stagn an t w a ter and temp orar y rain poo ls. Harmful by

s w a l l o w i ng, inh a lati on or skin contact. Can o n l yb e us ed und er an agre e ment bet w e en Eco l o g y and H ealt h in the event of a dise ase o u tbre ak. Aphi ds, leafh o p pers, grassh opp er s, spider mites, bugs, beetl e s, moths,

w o rms, flies, mosqu i toes, & larvae. *OPs are organo phosphates ** Res tri ctions c a n be waiv ed in the event of a thr eat to hum an he a t h as d e t e rm inedb y s t a t e andloc a l h eal th d e part m e nts (s ee p

. 16 ). *** EPA’s 2001 Methopren e R

. E.D. Fact Sheet stat es that metho p rene “has activity ag ains t a v a riety of insect species, in cluding hor n flies, m o squitoes, be et les, toba cc o m o ths, sci a rid fl y, f l e a s (eggs and larv ae) , f i re ants, phar a oh ants , midge flies andIndia n m eal

m o ths

. ” Howev e r, no ef fec tiven es s is cl aim e d ag ains t thes e insec t s at the dose lab e l r a te for m o squito l a rva e contro l.

Best Mana g e ment Practi ces for Mosq uito Control Page 1 7 Washington State Depar t ment of Eco l ogyWhen Adulticides Fit into a Mosquito Contro l Plan

Terrestrially applied pro d ucts are NOT regulate d un der federal or state water pollut i on control l a ws and are NO T subject to NPDES permit conditions or requirements whe napplied to terrestrial sites. However, adulticiding is often an in tegral componen t of an i n tegrated p e st manage m ent approach to
mosq uito control. In so me insta n ces, adulticiding can reduce or elimin ate th e need to heavily a pply larvi c ides, c an be used effectively wi th less envir o nmental i m pact to no n-targets, an d can be costeffective.

Select triggers for the use of adulticide products : Some mosq uito control districts recommend using light traps t o monitor for mosq uitoes. For exam ple, Adams County MD recommends tha t counts of 8 to 12 mosq uitoes caught in 12 hours or a 3 adu l t mosq uito landing count per minute in a residential area triggers the ne ed to adulti cide (Thomas Ha worth, personal communication, November 7
, 200 3). Som e applicators recommen d adulticiding residenti a l areas a n d upland areas where mosquitoes are migrating only when t h er e is evidence of mosquit o -borne epizootic activity at a level suggesting hig h risk of human infection. The following are examples of this type of evidence: high dead bird densities; high mosq ui to infection rates; multiple positive mosquito species incl uding br idg e vectors; horse or ma mmal cases indicating escalating epizootic transmissio n , including bridge vect ors, horse or mammal ca ses, or a human case with evidence of epizootic activity.

Reducing vector densities below tran smission thr e shold usually requi r es multiple UL V applications. Therefore, triggers should take into account this latency eff e ct so that human transmissio nis not proceeding prior to or duri n goperations. This presupposes identifying increasing human risk atleast 2 wee k s before human case s might prese n t. Trigger design and implementation should reflect this need for preemptive adulticiding.

BMPs for Adulticides:

1) Meteorological conditio ns:

• Record win d speed an d direction before spra ying and be obs e rvant of all changes in direction and speed during the appl ication. Use appropriate wind indicators. Gauge s are highly recommende d for groun d applicat ions and smo ke for aerial applications.

• For aerial applications, check temperature at di fferent elevations to decide if there is an inversion.

• Spray only when wind is away fro m sensitive sites. 2) Do not spra y in winds o v er 10 mph. 3) Follow label buffers.

The following table gives a s a mple of mosq uito adulti cides t hat may be used interrestrial applications in Washington State. La bels are available from http://picol.cahe.wsu.ed u /

.

Page 1 8 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyTable 4. Common Insecticides Used for Adult Mosquito Con t rol

T y pical P r od uc ts Ac t i v e Ingredient Lab e l Use Rate Use C os t Residu al Lif e C o mme nts

Biom i s t & Kontrol, Per m anone Aqua Res lin Per m ethr in ULV 4

o z

/ac r e A dult Contr o l $ .24/o z 24 hou r s Ef f e c t ive, 100 f t setbac k f r om w a ter

. Py r e n one 25- 5 P ublic Health Ins e c t ic ide P y r ethr in ULV 1- 4

o z

/ac r e A dult Contr o l $1.20/oz 1 hour No s e t- bac k s to

w a ter. Appr oved f o r
c r op a nd pas tur e applications

. Ex pen s i ve

Sc ourge Resm ethin ULV 4

o z

/ac r e A dult Contr o l $ .58/o z 1- 4 ho ur s H a s no t p e r f o r m ed

w e ll in s o m e ar eas

. No s e tbac k s to

w a ter. F y f a n on ULV M ala t hion ULV r a tes

v a r y Adult Contr o l $ .24/o z 24 hou r s Ver y h i ghly tox i c to nonta r gets

.

Anvil S um ithr in 0

. 0012 lb – 0

. 0036 lbs ai
p e r acre Adult Contr o l $ .40/o z 1- 4 ho ur s T e s t e d and us ed in the NW . No w a t e r pr ec a u tions

.

Di bro m , T r um pet Nale d Not

r e c o m m end ed f o r g r ound ULV

u s e. Adult c ontrol No s e t- bac k s to

w a ter. Appr oved f o r
c r op a nd pas tur e applications

.

What Constitutes an E m ergency or a H ealth Threat?

Health emergencies and health t h rea t s are declared by local health depa rtments in c o nsultation with Washi n gton Stat e Departmentof Health. A health officer should consider demographics, population densities a n d species of mosq uitoes, pr oximity of positive identifications of mosq uitoborne disease, and local tolerances for pesticide applications and disea s e outbreaks when a sses s in g risk.

Permitted insecticides may be applied to waters as conditioned by their FIFRA labels (includ i ng methoprene in restricted areas) once an applicatio n has been submitted b u t before pe rmit covera ge is granted a s a result of consultation between de pa rtments o f Health and Ecology, in response to a human he alth emergenc y or threat a s determine d by the Wa shington Sta t e Departme nt of Health.

If an e m ergency is declared or a threa t is determ ined, and mo sq uito control actions ha ven’t already been taken, the responsi ble offi c i als should immediately initiate actions t o minimize mosq uito breeding habitat and ed ucate at risk populations ab out personal protection (see p. 2); t h ey should then begin c o nducting larval surveys and secure the funding, permits and licenses needed for applying insecticides. For practical purposes, on ce an outbreak is underway, larval surveys and

Best Mana g e ment Practi ces for Mosq uito Control Page 1 9 Washington State Depar t ment of Eco l ogyother control and habitat minimizat ion measures will have lit tle immediate effect. At this point, personal protective measures and la rge-scale adul ticiding may provide the only mea n s to reduce human/vector contact and further spread of the disease bey o nd those already infected.



## Refer ences Cited

Colorado Mosquito Con t rol, Inc. Online at: www.comosquitocontrol.com/flood_ irrigation_&_mosquit oes.htm

. Lilja, Jack. 2 002. Mosquito-Borne Disease Respon se Plan, November 2002 E d ition . Washington State Departmentof Health. Online at: www.doh.wa. g ov/ehp/ts/zoo/wnv/wnv.html

. O'Malley, Claudia C. 199 5. Seven W a ys to a Successful Dipping Career. Wing Beats, vol. 6(4): 23- 24. American Mosq uito Con t rol Association.

Pratt, Harry D. and Moo r e, Chester G. 1993. Mosquitoe s of P u blic Health Importance an d Their Contr o l

. U.S. Department of Hea l th and Human Services, Cent ers for Disease Co ntrol and Prevention, Selfstudy Cours e 301 3-G: Ve ctor-Borne Disease Con t rol.

Von Grey, Ed. 200 2. Dra f t Appropriate Mosq uito Managem ent Strategie s as a Respo n se to Wes t Nile Vi rus. Washington State Depar t ment of Agric u lture.

Whitworth, Terry. 2002. Mosquito M a nagement Policy for Resi dential Stormwater P o nds in King County, Washington . King County Departme nt of Natural Recourses and Parks
, Water and L and Recours e s Division.

Page 2 0 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Appendix A State Listed Speci es Restricted Areas

Best Mana g e ment Practi ces for Mosq uito Control Page A-1 Washington State Depar t ment of Eco l ogyPage A-2 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Appendix A State Listed Speci es Restricted Areas

Basis of Rest rictions

Ecology’s Aq uatic Mosquito Control National Po llutant Discharge Elimination Syste m (NPDES) General Per m it No. WAG-9 9200 0 Condi t ion S4 3 s t a t es, “ I n deve loping the I P M plan, th e permittee shall consult with local governments and stat e and federal agencies as needed.”

Ecology took the lead d e veloping an IPM plan t o assist many local governments an d others performing mosq uito control operations who were suddenly in the b u siness of mosquito control due to the spread of t h e West Nile virus. As the permit required, Ecology consulted with the D e partment o f Fish and Wildlife (WDFW) in spring 2003 during this process. As a result, the WDFW identified wildlife species tha t it cons idered most vulnerable to certain mosquito contro l larvac ides, identified the primar y areas occupie d by these species, and r e quested that pesticide applications be rest ricted in these areas.

These areas, along with areas identif i ed as habitat for federal and state listed fish species were compiled into a document called Insert A and listed as area s wh ere larvicides co ntaining monomolecular surface films, methoprene, petroleum distillates, mala thion and temephos were not allowed for use. Larvicid es containing Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (BS) were allowed for use due to their low toxicity t o non-target s p ecies. Unfortunately, the recommendations for restrictions were given to Ecology after the mosq uito spray seaso nhad begun and in t h e i n terest of h a ving a permit pathway i nplace for applicators for the 20 03 sp ray

season Ecology listed th e recommendations a s Insert A and opened the m for public review after the season was

over.

The restrictions in InsertA have been considerably revised as a result of a more thor ough review initiated the fall of 2003 . Significantly, the restrictions on t h e us e of me thop rene in wate rs containing federal an d state liste d salmon hav e been lifted to allow monitoring for effects. The restrictions for state listed species that are still recommended by WDFW are listed here and a map of thos e areas is pr ovided. Restrictions spec ific to lar v ic i d e active ingredients are al so noted on Table 3

.

Criteria Use d for the Restrictions

The criteria WDFW used for denoting species as vulnerable were: 1) State spe c ies of concern ( i.e ., listed as st ate en dangered, t h reatened, s e nsitive, or candidate). 2) Current range a n d di stribution ofthe species was highly l o calized. 3) The species inhabited freshwater wetlands du ring most of the mosq uito control treatmentperiod.

Six species i n itially met those criteria: northern l e opard frog ( Rana pipiens ), Oregon spotted frog ( Rana preti osa ), western toad ( Bufo borea s ), western pond turtle ( Clemmys marmorat a ), American white pelican ( Pelecanus erythrorhynchos ), and one butterfly, the Yuma skipper ( Ochlodes yuma ).

WDFW identified areas occupied by the two extant popu lations of northern leopard frog; two extant western Washington populations of Oregon spotted frog; western toad breeding ponds (for western Washington onl y ); the

Best Mana g e ment Practi ces for Mosq uito Control Page A-3 Washington State Depar t ment of Eco l ogythree remai n ing wester n pond turtle populations; the singl e American white pelican breeding colony; and t h e one known Washington Yuma skipper population.

Based on the review of pub lished li terature, expert ad vice, and the vul n erability ofthese rare and endangered animals and their freshwater invertebra te food resources WDFW reques ted that if mosquito control is deemed necessary in the area s W D FW described in April 200 3, th at itbe restricted to the use of Bacillus products.

Aerial Applications

An exception to the WDFW request regarding the use of certain larvic ides was made for the single American white pelican breeding colony. The colony resid e s on island s and along the shores o f the Columbia River, south of the confluence of the Snake River, in Walla and B e nton counties. While bio-chemicals such as met h oprene were not of concern for the pe lican breeding colony, t h e method o f aerial application was b e lieved to be unacceptably disturbing for their successful breeding. It w a s agreed tha t aerial applications would not be ma de on the pe lican breeding areas, wh ereas less obtrusive methods o f mosq ui to control were acceptable near these sit e s.
Discussions among seve ral WDFW biologists found tha t ae rial applicatio ns of larvici d es disturbed work being done in a fe w wildlife refuge areas around the s t ate. It was therefore ag reed thatop erators making aerial applications over wildl i f e refuges should notify the appr opriate regional WDFW office of their scheduled aerial applications at leas t 24 h o urs prior to spraying. Th e notification can be made by phone or fax.

Area of Impact

Only a few populations of northern leopard frog, Oregon spotted frog, w e stern toad
, western pon d turtle, and Yuma skipper remain in Washingto n

. The tot a l area occupie d by these species in rivers, lakes, p o nds, and wetlands is tiny, comprising of portions of 11 7 s e ctions (<0.18% of Washi n gton Stat e). The areas identified for northern leopard frog (36 Sections) a n d western pond tu rtle (13 Sections) are owned or managed by WDFW. A prudent, ris k -adverse approach is warranted with vulnerable threate n ed and end angered spe c ies.

The following areas are restricted to the use of Ba cillus thuringiensis israelensis (Bti) and Bacillus sphaericus (H-5a5b) only. Sections added January 22, 2004 are in bold: 1) Grant Co unty, north of Moses Lake, with in t h e Crab Creek watershed: T21N R27E Sections 1, 12, a n d 1 3 ; T 21N R28E S e ctions 7, 1 7, 18, 19, 28, 2 9 , 30 , 31 , 32
, and 33

. 2) Grant Co unty, south and wes t of Moses Lake and south of Interst a te-9 0, the northe rn portion of the Potholes : T19N R27E Sections 33, 34, 3 5 , a n d 3 6 ; T19N R28 E Sections 31 and 32
, 29 , 30 ; T18N R27 E Sections 1, 2, 3, 4, 8, 9, 10, 1 1 , 1 2 , 1 3
, 14, 15, and 16, 17; T1 8 N R28E Sections 5, 6
, 7, 8, 17, and 18

. 3) Grant Co unty, area w i thin and n e ar the Sun L a kes

– Dry Falls State P a rk wetlands: T24N R27E and 28 E. 4) Kitsap C o unty: lakes
, ponds, a n d wetlands lo cated in T22 N R1W Sections 1, 2, 1 0
, 11, a n d 1 2

. 5) Klickitat County, west of the Klickitat River, all waters in T3N R12E Sections 28, 2 9 , 32 , and 33

. 6) Mason C o unty, on th e Kitsap Pen i nsula: lakes
, ponds, a n d wetlands lo cated in T23 N R2W Sections 11 , 12 , 13
, 14, 15, 22, a n d 23. 7) Pierce and Kitsap counties, Carney Lake, locat e d in T22N R1W.

Page A-4 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy8) Pierce, Thurston, and Lewis counties, wi thin the Nisqually River watershed: Alder Lake (or Alder Lake Reservoir), loca ted in tow n ships: T15N R4E and 5E. 9) Pierce County, south of Tacoma, Chambers C r eek and associated wat e rs in T20N R2E Sections 26 and 2 7

. 10) Skama n ia County, ea st of Carson, all waters i nT3N R8E Sections 23, 2 4 , 25 , 26 , an d 36; T3N R 9 E Sections 30 and 31

. 11) Thurston County, west of Yelm: lakes, ponds, and we tlan ds located in T17N R1E Sections 8, 9
, 1 6
, an d 21

. 12) Thurston County, s o uth of Olympia and ea st of Int e rstate-5, within the Black River watershed, t h e Beaver C r eek drainage, located in T16N R2W Sections 9, 10 , 11 , an d 12; T16N R1 W Section 7. 13) Thurston County, s o uth of Olympia and w e st of Interst a te-5, wit h in the Black River watershed: Black River proper from south of Bl ack Lake to the Chehalis Rive rconfluence, and the following tributar ies, Stony Creek, Demp sey Creek, SalmonCreek, and Blooms Ditch. Legal description as follows for these s e nsi t ive areas: T 17N R3W Sections 10, 11 , 12, 13, 14, 1 5 , 23 , 24
, 25, 3 5 , a n d 3 6 ; T17N R2 W Sections 7, 18 , 19 , an d 30; T1 6N R3W Sections 2, 11, 14, 19, 2 0 , 2 1 , 2 2
, 23, 3 0 , a n d3 1; T16N R4 W Sections 25, 2 6 , 2 7 , 3 1 , 32, 33, 34, 3 5 , and 36.

Best Mana g e ment Practi ces for Mosq uito Control Page A-5 Washington State Depar t ment of Eco l ogyPage A-6 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Appendix B Insect Repellent Use and Safety

From the Center for Disease Control

Best Mana g e ment Practi ces for Mosq uito Control B-1 Washington State Depar t ment of Eco l ogyB-2 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Appendix B Insect Repellent Use and Safety

From the Center for Disease Control

Q. Is DEET safe? A . Yes, products containing DEET are very safe when used according to the directions. Because DEET is so widely used, a great d e al of test ing has been done. When manufacturers seek registration with the U.S

. Environmental Protec tion Agency (EPA) for products such as DEET, laboratory testing regar d ing both short-term and long-term health effect s must be ca rried out. Over the long history of DEET use, very few confirmed incid e nts of toxic reactions to DEET have occurred when the product is used proper ly. (From the National Pesticide Information Center [NPIC], EPA re-r egistration eligib ility dec i sion. See npic.orst.edu/factsheets/DEETgen.pdf

. )

Insect Rep e l l ents and Su nscreen
Q. Can I use an insect repellent con t aining DEET and sunscreen at the s a me time? A. Yes. People can and s h ould use both sunscree n and DEET when t h ey are outdoors to protect their health. Follow the instructions on the pack age for proper application of each pr oduct. Apply sunscreen first, followed by repellant containing DEE T

. To protect from sun exposure and insect bites, y o u can also wear long sleeves and lo ng pants

. You can also apply insect repellent containing DEET or permethrin to y o ur clothing, rather th an directly to y o ur skin.

Q. Has C D C changed its recommendati ons for use of DE ET and sunscreen? A. No. Based on available research, CDC believe s it is safe to use both products at the same time. Follow the instructions on the package fo r proper ap plication of each product. Apply sunscreen first, then ins e ct repellent containing DEET, to be sure that eac h product w o rks as specified.

Q. Should I use a combination sunscreen/DEET -based insect repellent? A. Because the instructions for safe u s e of DEET and saf e use of sunscreen are different, CDC does not rec o mmend using products that combin e DEET with sunscreen.

In most situations, DEE T does not n eed to be re applied as freq uently as sunscreen. DEET is very safe when applied correct ly. The rare ad verse reactions to DEET have generally occu rred in situations where people do not follow the pr oduct instructions. Sunscreen often re q u ires frequent reapplication, so using a combined product is not recommende d . You do not need to reapply insect repellent every time you rea pply s u nscreen. Follow the instructions on the package for each product to get t h e b e st results.

Best Mana g e ment Practi ces for Mosq uito Control B-3 Washington State Depar t ment of Eco l ogyQ. I heard about a study saying that there may be some typ e of interaction between repellents containing DEET and sunscreen. Is this true? A . There has been att e nti o n to a s t udy concer ning the chemic als in DEET and sunscre e n presented at a scientific meeting. Thi s is an in vitro study, which means that it is a la boratory study that d i d not include human o r animal test ing. The go al of the study was to examine absorption of these ch em icals, and it did not ev aluate or mak e conclusion s about heal th effects related to this issue. The study auth ors stated th at further evaluation of the interaction of thes e chemicals should be conducted. The study ha s not yetbee npublished (as of July 2003).

Evaluation by the EPA, which regulates products su ch as DE ET, indicates that it is safe to use insect repellents cont aining DEET and sunscreen at t h e s a m e time. CDC recommends using two separate products because sunscr een requires fre q uent applic atio ns while DEET should be used sparingly. Follow the directions on the package f o r each product, and consult your physician or pharmacist if you have questions. C D C's recommend ations for the safe use of insect repellents on children and adults r e main unchanged.

Insec t Rep e l l ent Use

Q. Why sh ould I use insect repellent? A. Insect repellents hel p people re duce thei r exposure to mosq uito bites th at m a y carry potentially serious viruses such as West Nile vi rus, and allow them to continue to play and work outdo o rs.
Q. When should I use mosquito repellent? A. App l y re pellent when you are going to be outdoors and will be at risk for getting bitten by
mosq uitoes.

Q. What time of day s hould I wear mosquito repellent? A. Many of the mosquitoes that carry the West Nile vir u s are especially likely to bite around dusk and da wn. If you a r e outdoors around thes e times of the day, it is i m portant to apply repellent. In many p a rts of the country, there ar e mosquitoes that also bite during the day, and these mosquitoes have al so been found to carry the West Nile virus. The safestdecision is to apply repellent whe n ever you are outdoors.

Q. Ho w often should repellent be reapplied? A. Follow the directions on the product you ar e using in order to determine how frequently you need to reapply repellent. Swea ting, perspiration or gett ing wet may mean thaty o u need to re-apply repellent more frequently. If you are not being bitten, it is notnecessary t o re-apply repellent. Repellents containing a h i gher concen tration of a c tive ingredient (such as DEET) provide longer-lasting protection.

Q. Should I wear repellent while I am indoors? A. Probably not. If mosquitoes are biting you while you are in doors, there are probably better ways to pre v ent these bites instead of wearing repellent all the time. C h eck window and door screens for h o les that ma y be allowing mosq uitoes inside. If y o ur house or apartment does not have screen s, a q u ick solution may be to staple or tack screening (available from a hardware

B-4 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogystore) across the windo w s. In some areas comm un ity programs can hel p older citiz e ns or other s who need as sistance.

Q. Ho w does mosquito repellent work? A. Female mosquitoes bite people and animals be cause the y need t h e p r otein found in blood to help develop their eggs. Mosquitoes are attracte d to people by skin odors and carbon dioxide from breath. Many repellents contai n a chem ical , N,N-diethyl-m-toluam ide (DEET), which repels the mosquito, making the per s on una ttrac tive for feeding. DEET does not kill
mosq uitoes; it just makes them unable to loca te us. Repellents are effective only at short distances fr om the treated surface, so you may st ill see mosquitoes flying nearby. As long as you are not getting bitte n, there is no reason to apply more DEET.

Q. Which mosquito repellent works the best? A. The mos t effective repellents contain D EET ( N ,N-diethyl-m-toluamide), which is an ingredient used to repel pests like m o sq uitoes and ticks. DEE T has been t e sted ag ains t a variety of biting insects and has been show n to be very effective. The more DEE T a repellent contains the longer ti me it can protect you from mosquit o bites. A higher percentage of DEET in a repellent does not mean that your protection is better—just that it will last longer. DEET concentrations higher th an 50 percent do not increase t h e length of protection.

Q. Ho w does the percentage of DEET in a produc t relate to the amou nt of protection it gives? A. Based on a recent stu dy:

• A product containing 2 3

. 8 percent D EET provid ed an averag e of five hours of protection from mosq uito bites.

• A product containing 2 0 percent DEET provid ed almost four hours of protection

• A product with 6.65 pe rcent DEET provid ed almost two ho urs of prote c tion

• Products with 4. 75 percent DEET an d 2 percent soybean oil were both a b le to provide roughly one and a half h o urs of protection.

Choose a repellent that provides pr otection for th e amount of time that you will be outdoors. A higher percentage of DEET should b e used ifyou will be out d oors for several hours while a lower perce n tage of DE ET can be used if time ou tdoors will be limited. You can also re-apply a product if you are outdoors for a longer time th an ex pected and st art to be bitten by
mosq uitoes. (For more information, see Table 1: Fradin and Day, 2 002. See Publications page.)

Q. Why does CDC recommend using DEET? A. DEET is the mosteff e ctive and best-studied insect repellent available. (Fradin, 199 8). Studies usin g humans a n d mosq uitoes report that only products containing DEET offer longlasting protection after a single application.(Fradin and Day
, 2002 . See Publications page.)

Q. Are non -DEET repellents effective (e .g. Ski n-So-Soft, plant-based repellents)? A. Some non-DEET repellent products which are in tended to be applied directly to skin also provide some protection from mos q uito bites. However, studies have suggested th at other products do not offer the same level of protection, or thatprotection does not las t as long as products containing DE ET. A soybean-oil-based product has been shown to provide protection

Best Mana g e ment Practi ces for Mosq uito Control B-5 Washington State Depar t ment of Eco l ogyfor a period of time similar to a product with a low concentration of DEET (4.75%) (F radin and Day, 2 002. See Publications page.).

People should choose a repellent that they w ill be likely to use consistentl y and that will provide suff icient protec tion for the amount of time that they will be spending outdoors. Product labels often ind i cate the length of time t hat protection thatcan be ex pected from a product. Pe rsons who a r e concerned about using DEET may wish to co nsult their health care provider for advice. The National Pesticide Information Cent er (NPIC) can also provide information through a to ll-free number, 1-800- 858 -7378 or npic.orst.edu

. Q. I'm confused. Which products contain "DEET"? A. Most insect repellents that are av ailable instores are labeled with the chemical name for DEET. Look for N,N-die t hyl-m-toluamide or, sometimes, N, N-diethly-3-methylbena mide. Choose a re pellent that offers appropriate prot ection for the amount of t i me you will be outdoors. A higher percentage of DEET should be used if you will be outdoors for several hours while a lower percentage of D EET can be used if time outdoors wi ll be limited.

Using Rep e l l ents Safely

Q. What are some general considerations to remember in order to use products co ntaining DEET safel y ? A. Always follow the recommendati o ns appearing on the product label.

• Use enough repellent to cover e x posed skin or clothing. Don ' t apply repellent to skin that is unde r clothing. Heavy application is notnecessary t o achieve protection.

• Do not apply repellent to cuts, wounds, or irritated skin.

• After returning indoors, wash tre a te d skin with soap and w a ter.

• Do not spray aerosol or pump prod ucts in enclosed areas.

• Do not apply aerosol or pump products dire ctly to your face. Spray your hands and then rub the m carefully over the face, avoiding eyes and mo uth.

Q. Ho w sh ould products containing DEET be used on children? A. No definitive studies exist in the scientific literature about what co nce n tration of DEET is safe for children. No se rious illness has been linked to the use of DEET in children when used according the product recommendati o ns. The American Aca d emy of Pe diatrics (AAP) Committee on Environmental Heal th has recent ly updated their recommendation f o r use of DEET prod ucts on children, citing: "Insect repellents contai ning DEET (N,N-diethyl-mtoluamide, also known a s N,N-diethyl-3-methyl benzamide) with a conce n tration of 1 0 percent appear to be as s a fe a s products with a concen trat ion of 30 percent when used according to the directions on the product labels."

The AAP and other ex perts suggest t hat it is acceptable to apply repellen t with low concentrations of DEET t o infants ov er two mont hs old. Other guideline s cite that it is acceptable to use repellents containi ng D EET on children over two years of age.

B-6 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyRepellent products that do not conta i n DEET are not likely to offer the sa me degree o f protection from mosq uito bites as products containing DEE T . Non-DEET repellents have not necessarily been as thoroughly studied as D EET, and may not be safer for use on children.

Parents sho u ld choose the type a n d concentration of repellent to be used by taking into account the amount of time that a child will be outdoo rs, exposure to mosquitoes, and the risk of
mosq uito-transmitted disease in the area. Pe rso n s who are concerned about using DEET or other products on children may wish to consult their health care provider for advi ce. The National Pe sticide Information Cent er (NPIC) can also provide information through a toll-free number, 1-800-85 8-73 78 or npic.orst.edu

. Always follow the recommendatio ns appearin g on the product label w h en using repellent.

• When using repellent on a child, apply it to your own hand s and th en rub them on y o ur child. Avoid children's eyes and mo uth and use it sparingly around their ears.

• Do not apply repellent to children's hands. (Chi ldren may t e nd to put t h eir hands i n their mouths.)

• Do not allow young children to apply insect re pellent to the mselves; ha ve an adult do it for them. Keep repellents out of reach of children.

• Do not apply repellent to skin under clothing. If repellent is applied to cl othing, wash treated cloth i ng before wearing again

. Using repell ents on the skin is not the only wa y t o avoid mosq uito bites. Children an d adults can wear clothing with l o ng pants a n d long sl eeves while outdoors. DEET or other repellents such as permethrin can also be applied to cl othing (do not us e permethrin on skin), a s mosquitoes may bite thr o ugh thin fabric. Mosquito netting ca n be used over infant carriers. Finally, it may be possible to reduce the number of mosquitoes in the are a by getting rid of containers with sta n ding water t h a t pr ovide breeding places for the mo squitoes.

Q. Is DEE T safe for pregnant or nursing wome n? A. There are no reported adverse e v ents following use of repellents containing DEE T in pregnant or breastfeeding women.

Q. Are there any risks due to using repellents containing DEET? A. Use of these products may cause skin reactions in rare cases. If you su spect a react i on to this product, discontinue use, wash the t r eated skin, and call your local po ison control center. There is a new nati o nal number to reach a Poison Cont rol Center near you: 1-8 00-22 2-12 22.

If you go to a doctor, tak e the product with you. Cases of serious reactions to products containing DEET have been related to misuse o f the product, such as swallowing, using over broken skin, and using for multip le days withou t washing sk in in betwee n use, for example. Always foll ow the instructions on the product l a bel.

Best Mana g e ment Practi ces for Mosq uito Control B-7 Washington State Depar t ment of Eco l ogyMore information

Q. Where can I get mor e information about repellents? A . For more information about using repellent s s a fely please consult the EPA Web site: http://www.epa.gov/pestici des/citizens/inse c trp.htm or consult the National Pe sticide Information Center (NPI C), which is cooperativ ely sponsored by Oregon State University and the U.S. EP A. NPIC can be reached at: npic.orst.edu or 1-800 -858-7 378.

B-8 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogy

# Appendix C

Response to Public Comments

Best Mana g e ment Practi ces for Mosq uito Control C-1 Washington State Depar t ment of Eco l ogyC-2 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyAQU ATIC MOSQUIT O CONTR O L GENERAL P E RMIT RESPONSE TO COMME NTS

RECEIVED DURI NG TH E PUBLIC C O MMENT P E RIOD FO R 

### GENERAL NPDES PERMIT WAG-992000 MODIFIC ATION AND THE BEST MANA GEM N T PRACTI CES FOR M O SQUIT O C ONTROL

This append ix contains Ecology’s response to co mments to t h e Mosq uito Control General NPDES Permit WAG-9920 00 M o dification and change s to the Be st Managemen t Practices for Mosquito Control (BMP) document received during a pu blic review period from December 15, 20 03, to March 25, 2 004.

Prior to the formal pub l i c review per i od the De p a rtments of Health and Fish & Wildlife, many
mosq uito control districts, loca l governments, m o sq uito control product manufacturers and oth e r interested parties worked with Ecology to revise the st atewid e permit and BMPs to make them more pertinent an d usable for those conducting mosq uito co ntrol efforts in the field. Meetings were he ld October 14 and 15 in Mo ses Lak e , on October 21 in Lacey, a n d again on March 5 in Olympia, at the Washington State Depar t ment of Ag riculture. As a result, Ecology received many inf o rmal comments and suggest ions thatwe re incorporated into the proposed modifications.

Formal comments recei v ed during t h e publi c co mment period pertain t o wetlands, the use of methoprene and oth e r mosq uito control products, threshol ds for larvi c iding (incl u ding preemptive methods of control), adulticiding, dipping requir ements, suggestions fo r clarification, and o t her miscellaneous comments.

Commenters

1. Joseph M. C o nlon, American Mosq uito Control Association
2. Karl Malamud-Roam, Ph.D., Contra Costa Mosqui to & Ve ctor Control District, Concord, CA
3. Steve Foss and Wendy S u e Wheeler, Washingt on State Depar t ment of Ag riculture
4. Ann Potter and Rocky Beach, Washi n gton Stat e Departmentof Fish & Wildlife
5. Tom Haworth, Adams C o unty Mosquito Control District, WA
6. Kevin Shoemaker, Northwest Mosq uito and Vector Control Association
7. Heather Hansen, Wa shi n gton Frien d s of Farms and Forests
8. LaDell Yada, Washingto nState citizen
9. Lou Dooley, Environmental Health Director, Clark County Mosquito Control District
10. Doug Van Gundy, Wellmark Intern ational
11. Will iam Meredith, Delaware Mosquito Control Section, Department of Fish and Wildlife
12. Wayne Switzer, Eden A d vance Pest Technologies
13. Art G. Losey, Washingt on State Pes t Control Association
14. William Peacock, City of Spokane
15. Jim Thompson, Grant C o unty Mosquito District #1

Best Mana g e ment Practi ces for Mosq uito Control C-3 Washington State Depar t ment of Eco l ogy16. Jim Tabor, WDFW
17. Mike Young
, Snohomish Health District
18. Gerald Campbell, Grant County Health District
19. Mark Newberg, Wellmark Internatio nal
20. Benjamin H a milton, Washington State Department of Health
21. David Ensunsa, Columbia Mosquito Control District
22. Dan Mathias, City of Everett

Comments have been s u mmarized and tho s e commenting are referenced by the nu mber given to them above. Where comments resulted in a change to either the B M P document or the per m it, thatcha n ge is noted.

Wetlands

Comment 1. The role of natural predation in the control of mosq uitoes in the document and the webpage from which it is derived is somewhat over stated. Although there is a weal th of literature recording o b servations and extolling the importance of the Odonata as predators of diurnally ac tive adult mosquitoes, this has no t been supported by co ntrolle d field studi e s. While predation provides a worthy and welcome contribution to our integrated mosq uito control efforts, it simply cannot provide the level of control neede d when human lives are at s t ake Th is is certainly not mea n t to downplay the important part proper wetlands m a n a gementplay s in ecology and a fully-integrated mosq uito manage m en t strategy, for the American Mosq uito Co ntrol Association fully supports and endorses proper wetlands m anag ement. But I would caution ag ainst promulgatin gthis as the sole mean s of mosquito control in areas where t h ese wetlands are found. I would advis e further caution agains t underestimating the potential magni t ude of mosquito prod uction even in natural, healthy wetlands. (1, 11, 12)

Response to Comment 1. Mosquito "outbreaks" most often occu r in destabilized wetland and stream ecosyste m s th at have been changed or tampered with so th at the predators of the larv ae such a s invertebrat e s , insects, and amphibians ar e excluded. Ecology does not su ggest that predation i s th e only me ans of mosqui to control for wetlands. Whil e draining and/or filling wetlan ds are not approved method s, taki ng an integrated approach that targets mosq uito larvae co ntrol, including bio-chemical control, is recommende din the BMPs. (Tom Hruby, Ecology Wetland Specia list, Personal C o mmunicatio n , 1/16/04)

Methoprene

Comment 2

. This comment addres se s the is sue of restricting the use of m e thoprene in areas k n o w n to provide habitat for state threatened a n d enda nge r ed species during the mosq uito spray season

. There were divergent views o nthe propos ed restrictions. One view suggests t h e restrictions are unnec e ssary, the other suggests precaution due to unknowns. Let it be not e d thatthe WDFW restricted areas are the only conditions for met h oprene in t h e Permit th at are more stringent th an the application conditions set by FIFR A labels.

View 1. The 200 1 USEPA document together wi ththe 20 03 USEPA research and th e World Health Organization/FAO review state that me thoprene will have minimal adverse effects on non-target species. The Fish and Wi ldlife le tter pretty dramatically overstate s the risks

C-4 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyassociated with this product. Decisions should be made on sound science. Methoprene should be allowed in areas identified by W D FW to mini mize the potential increase use of adultic i des, which will li kely result due to insuffi cient cont rol of third and fourth instar larvae usin g Bacillus products only. (1, 2, 3, 5 , 6, 7
, 8, 9, 1 0
, 12, 13, 15, 1 8 , 19 , 41)

View 2. We [WDFW] appreciate Mr. VanGun dy's [VanGund y represents Wellmark Internation a l, a manufac t urer of methoprene pr oducts] expla nation regar d ing the contents of the EPA RED documents. We notice that EPA do es denote a l e vel of amphibian tox i city from methoprene ("minimally tox i c to amphibians"). In our Octo ber 13 letter, we state that research on methopr e ne and frog deformities is inco nclusive. There are studies that have found developmental effects to amphibians when me tho p rene was a pplied at mosq uito control
treatmentlevels, and there are studies that have no t observed this. We d o not think i t would be productive t o engage in debate/rebuttal over al l research on this matte r. Because t h e body of research on this topic is not definitive we hav e c h osen to use the precautionary principal when conserving state and end angered spe c ies. We di d not feel thatthere wa s sufficient information to recommend tha t met h oprene products be rest ricted other than in very localized areas wh ere we have ide n tified T & E species. G i ven that we are making recommendations for st ate threatened and endange r ed species, in very limit ed areas, an d that o t her efficacious mosq uito control prod ucts ( Bacillus ) are available, we continue to support our original recommendation on methopr e ne restriction. (4, 16)

Response to Comment 2. Aquatic Mosquito Control Permit No. W AG – 9920 00, Section S 4 . Best Management Practices/Integrated Pest Management requires the preparation a n d implemen tation of an In tegrated Pes t Manageme nt Plan (IPMP) by the permittee. Among other conditions, the sectio n states, “in developing the IPM plan, the permitte e shall consult with local government s an d state and fe deral agencie s as needed.” The P ermit Fact Sheet provides the following rati o nale for this condition: ...an IPM program consid ers all avail a ble control ac ti ons, including no action, and evaluates the interaction a m ong various control practices, cultural practices, we ather, and habitat structur e. This approach thus uses a co mb ination of re s o urce man a ge ment techniques to control mosquito po pulations with decisions based on su rveillance. Fish and game specialists an d natural resou rces biologi s ts should be involved in planning control mea s ure s whenever de li cate ecosyste m s could be impacted by mosquito control practi ces (p. 9).

Ecology took the lead developing an IPM plan to ass ist local gover n ments and o thers perfo r ming mosquito control operation s w h o were sudd enly in the business of mo s q uito co ntrol due to the spread of the We st Nile virus. As the permit re quired, Ecology consulted with the Departmentof Fi sh and Wildlife (WDFW) i n spring 2003 during this process. WDFW identified wildlife species that it considered most vulnerabl e to certain mosquito control larvacides, identified the primary areas occupied by these species, and request ed that pesticide applications be restricted in t h ese ar eas. Ec ology also invited repres ent a tiv es fro m the industry to comment on t h e basis of the WDFW reco m mendations . An evaluation of the issu e yields the following facts:

1. The criteria WDFW used for denoting s p ecies as vuln erable w ere a ppropriate. Only those listed as st ate endangered, threatened, se nsitive, or cand idate species that inhabited freshwat e r wetlands du ring most of t h e mosquito con t rol tre a tmen t period were considered. Five species me t the criteria: n orthern le opard frog (Ran a pipiens), Oreg on spotted frog (Rana pret iosa), we ste r n toad (Bufo borea s), we ster n pond turtle (Clemmys

mar m o rata), and one butte rfly, the Yuma skipper (Oc h lodes yuma)

.

Best Mana g e ment Practi ces for Mosq uito Control C-5 Washington State Depar t ment of Eco l ogy2. The total are a occupied by these species i n rivers, lake s, ponds, and wetlands is ti ny, comprising of portions of 117 sections (<0.18% of Washington State). Many areas identified for northern leopard frog (36 Sections) and weste r n pond turtle (13 Sectio ns) are o w ned or managed by WDFW.
3. EPA’s Methoprene Registration Eligibility Document (R ED) is dated March 1991. This docu ment has not been updated. A Fact Sheet for the RED was updated in 200 1. TheRED document states, “The Agency do es have data, however, that s h ow that met h oprene is highly acutely toxic to estuar i ne invertebr a tes” (p. 12). The Fact Sheet for the RED document updates this ass ess ment and des c ribes the level of amphibia n and fish toxicity from methopren e a s "minimally toxic" but do es not define what that me ans or explai n if that is sufficiently protective for f e derally and state listed species of concern. The World Health Org a nization indicates met h oprene is sli ghtly toxic to fis h but lists no data on amphibians.
4. Recent res ea r c h on methoprene and frog deformitie s a n d de velopmental toxicity is inconclusive. For examp l e, La Clair el al. (1998) found that methoprene breaks down quickly in sunlight and very low concentrations of the byproducts from degr adation interfe r e with n orma l amphibian development. The La Clair study concluded “the addition of 1μL/L of sev eral of S- met h oprene’s degradates t o the environmentof developing [amphibian] e m bryos r esult ed in juveniles with deformit ies simil ar t o that found naturally.” Ankley et al. (1998) found that UV light caused amphibian limb malformations whereas methoprene did not. The study further reported that concentrations of 500 p p b of methop rene caused mortality in amphibians. Degitz et al. (2003) was unable to reproduce the results of the La Cl air study, but did determine that methoprene and its metab o lites di d not cause a n y adverse eff e cts at rat es < 1.25 ppm. These data a r e too dispara t e to be conclusive. E v en though ri sk levels appear to be low, much uncertainty still exists with both the concentration s and the role methopren e and its metab o lites playwi th the normal development of amphibians.
5. Levels of me t h oprene that may be found in the envi ronment afte r mosquito con t rol applications ar e also variable. Co ncentrations have ranged from 4 ppb at seven days post treat ment f rom an Altosi d 30-day briquette (Ross et al 1994) to 0.01 p p m from sustaine d-release formulations (Degitz et al. 2003). Henrick, et.al. (2002) f o und 26 ppb s-methoprene in ponds treated with Altosid Liquid La rvicide (ALL) at day one, and 1 ppb at day seven. However, one of the metabolites, 7

- methoxycitronellal acid, was found at 267 ppb at da y 1 and 237 ppb at day 7. N o tably, these levels do no t r e present mult iple treatmen t s or potenti a l accumulatio n or any numbe r of other fact ors, such as s h ade, wind, wa ter fl ow, te mperatu re, pH, turbidity, etc. that may affect concentrations of applications to the natural env i ronment.
6. Several studi es concluded that a dose-ex posure co nne ction between frog deformit ies and metho p rene applications for mosquito c o ntrol is unli kely and that correlati o ns b e tween l o cati ons of methoprene applications for mosquito operations and frog deformit ies have not been found (Henrick, et.al. 2002, Johnson et.al. 2001, A n kley et al. 1998).
7. Larvicides containing Bacillus thuringi ensis israelensis (Bti) and Bacillus sphaericus (BS) are allowed for u se in these are as due to their extreme lo w to xicity to non-target species

. 8. The restricted areas identified by WDFW may pose a t h reat to human health when used as breeding grounds by mosquito vectors due to the narrow wind ow of eff e ctiveness of Bacillus products.

Ecology proposes t o allow the use of met h op rene in more than 99% of the state a s conditioned by the federal FIFRA label but will continue to rest rict the areas of application for meth oprene as recommen d ed by WDFW except in the event of a human health threat fro m mosquito -bor ne disease as determin edby the State and local health department s. Monomolecular films, oils and organophosphates are also restrictedin these areas, but the restrict ion on the use of methoprene was questi o n e d due to its low toxicity to non-targ ets and high selectivity for mosquito larvae.

To aid future decisions reg arding the use of methoprene Ecolo gy will complete a SEPA checklist evaluation of the use of methopren e for mosquito c o ntrol ope rati o ns and initiate a monit ori ng strategy to document concentration levels of methopren e a pplications in relation to po ssible advers e effects to non -target specie s. Many individuals, including people

C-6 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyrepres enting mosquito dist ricts, local government s, Wellma rk an d WDFW have offered to r e view and/or assist with the monito ring strategy. We intend on taki ng advantage of these o ffer s . The objective of the evaluation and monitoring plan will be to provide data on methoprene for decisions relevant to permit renew al b yNovember 2006.

Comment 3. Page 13 of the BMP under permitted pesticides for mosq uito control: The chart sho u ld be corrected to show specifically listed pests for Altosid products. Under the heading “T arget Pests on Label,” the identified species in the c hart for Altosid indicates a vari ety of pests. There are other m e thoprene la bels that reflect these pests but for Altosid, mosq ui toes are the only list e d species. ( 10)

Response to Comment 3

. Agreed, the chart has bee n edited. Howev er, EPA’s 2001 Methoprene R.E.D. Fact Sheet states that me thoprene “has activi ty against a variety of insect species, includ ing horn flies, mosquitoe s , bee t les, tobacco moths, sciari d fly, fleas (eggs and larvae), fire ants, pharaoh ants, midge flies an d In dian meal moths.” This information has been note d as a footnot e to the chart.

Comment 4. The statement in Comment 2, that “We do no t think it would be productive to engage in debate/rebuttal over all research on this m a tte r [methoprene and amp h ibians],” is frankly stunning. I do n o t believe that I have ever seen a gover n ment e n tit y expr ess the thought that they do not want to review the scientific fac t s on a controversial issue. Given that Ecology's proposed alter natives to methoprene are frequently less effective in numerous circumstan ces, t hatresistance m ana gement t h rough pesticide rotation is a cornerstone of modern IPM, and th at USEPA and numerous other inde pendent reviewers have found "minimal toxicity" or equivalent wo rding, the proposed prohibition shoul d not occur without strong scientific evidence supporting it, and this has not been provided. (2)

Response to Comment 4. The comme nt referr ed to in the above statem ent, ma de by WDFW, was explained in the context: “Because the body of rese arch o n this topic is not de finitive we have chosen to use the precautionar y principal when conserv ing state and endangered s p ecies. We did not feel that there wa s suf ficient information to reco m mend that methopren e products be restricte d other t h an in very localizedareas where we have identified T & E species. “ They did review scienti fic facts, it was the lack of evidence regard ing methoprene’s t o xicity that lead them to r e commend the precautionar y principle.

Comment 5. The WSDA would like t o inform Ecology that t h e Cent ers f o r Disease C o ntrol and Prevention, (CDC), recommends t h e alternation of bioration a l larv icides (Bti and Bs) and insect g r owth regulators (methopren e) annually or at longer intervals to prevent the development of insecticide resistanc e in vector populations. The WSDA recommends tha t the restrictio n of the use of Bti and Bs o n ly in certain areas identified in the BMPs b e amend e d by allowing some us e of methoprene in rotation and in combination with the approved biorational larvicides so as to prevent the deve lopment of resistance to Bti and Bs. ( 3 )

Response to Comment 5

. Since the restriction on the use of methoprene applie s only in very select sites th e rotati o n process r e commended woul d not be precluded in 99% of the state.

Further, in discussions wit h mosquito co ntrol operators around the state, we fou n d that resist ance to Bacillus products has not been f o und.

Comment 6. The language allowing local jur i sdi c tions to de clare a healththreat so th ey have acce ss to methoprene is very unclear. This B M P gives no guidance as to how loca l boards of health are to be proactive in protecting the comm unities or what t h resholds should be used to de termine the potential for human he alth risks. Incon s istent mo sq uito control thresholds c o ul d result i nwater quality problem s and peopl e taking illegal contr o l measures into their own hands. (7, 16, 17)

Best Mana g e ment Practi ces for Mosq uito Control C-7 Washington State Depar t ment of Eco l ogyResponse to Comment 6

. Permit condition S1.4. restricts the use of methopren e in area s des ignated by Washington State Depart ment of Fish and Wildlife except when a heath threatexists in those areas as det ermin ed by the State and local health departments. No health-b as ed thresholds are st ated in the BMPs or t h e permit. The Depart me nt of Health request ed that health-based determinati o ns be stated i n gen eral ter m s becaus e the process and criteria used by local health jurisdictions to deter m ine health threats is dependent on loca l conditions such as demographics , population densities and species of mosquitoes, proximity of positi ve identifications of mosqui to-borne disease, toleran ces for pesticide applications and tolerance s for disea se o u tbreak s. Ho wever, the la nguage on page 16 of the BMP under the section, “What Constitut es an Emergenc yof Health Threat?” has been clarified.

Comment 7. Page 3, par a graph 3. Re garding the statem ent in the BMP t h at met h oprene is an end o crine disrupter, this state m ent is untrue and I would propose thatt h is languag e be removed from the revised BMP. While endocrine disrupti on is becoming an area of co ncern, there are still ongoin g discussions sur r ounding testing methodologies. Currently there is a lack of va lidated test sy stems. Methoprene does not di srupt the production of any gland ular hormon e within ins e cts, othe r i n vertebrates, vertebrates or mammal s . In in sects it merely augments naturally occurring insect ju venile hormone (JH) at t i mes in the i n sect life cycle where natural production of JH is at a mi ni mum. An example would be during the molt from the last larval instar to the pupa or adult stage. I have included a more detailed commentary a s Attachmen t 1. I nma m m alian systems , me thoprene is broken down and excreted primarily through urine. (10)

Response to Comment 7. Ecology agrees, the stat e m ent has be e n removed.

Comment 8. There has b een much discussion of the non-t a rgeteffects of methoprene. As I outlined in my other correspondence, t h ere exists a wide margin of safe t y t o non-target s when met h oprene is used according to label dire ctions. There is no concern for accumulati on of methoprene in the e n vironment as itrapidly degrades, further Henrick et al. 2 002
, report that t h e degradati o n products of methoprene rapidly degrade as well, without accumulation. Methoprene can be u s ed with co nfidence ag ainst mosq uito larva but also provides for wide safety margins to non-targets. (10)

Response to Comment 8

. While there is no evidence that the use of methopr e ne for mosquit o control will lead to amphibian malfor m ation s or other adverse effects t o non-target s, t h e data are in conclusive. Scant monitori ng has been done of metho p rene applications for mos q uito control in th e natural environment . Ecology is initiating a monitoring strategy to document concentration level s of methoprene applic ations in the environment and will evaluate those levels i n relation t o possible advers e effects to non -target specie s.

Comment 9

. Page 18. T h ere are so me errors in the chart t h at need correction. The Altosid Liquid use rate should be changed to 3- 4 ounces per acre instead of 2- 20 pou n ds per acre. The 2-2 0 p o und rate is incorrect for this formulation. The ra te for Altosid XRG should be change d from 8-10 pounds to 5- 20 pounds t o reflect the label rate. I nthe target pest categor y there are a variet y of pests listed fo r the Altosid products. While this list is inclusi v e of several pr oduct lines, it does not r e flect the fac t thatthe Altosid products are labeled only for
mosq uitoes. I would suggest th at pricing be removed fromthe chart. Pr icing is subject to chang e by time an d location. Since the BMP is a document that will exist fo r some time, the pricing that is stated now in the BMP may not be i n dicative of a current pri c e for futu re referrals to the BMP. (10)

Response to Comment 9

. The errors have been corrected. Prices, b ased on 2002 levels, will be retained only as a general guide for cost comp arison s, one o f

the factors for consider ati o n in an IPM plan.

Comment 10. Methoprene's Imp a cts To Amphibians? -- A few years ago, the U.S. Fish and Wildlife Service (USFWS) imposed a condition for methoprene's use on one o f our two National Wildlife Refuges that

C-8 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogymethoprene not be applied over wetlands w h ere the salinity was less tha n5 ppt, don e in whatap peared (at least to us) to be an overly-zealous application o f the precautionary principle, becaus e of the service's supposed concerns about the impact s of methop rene uponthe developmental s t ag es of amphi b ians (which of course are found more typically in freshwater h a bita ts th an in salt mars hes, h e nce t h e Service's 5 ppt demarcation). However, this restriction only lasted for one y e ar in relation to our the nquestioning the USFWS's scientific foun dations abo u t their position -- afte r further review of the scientific eviden ce, it then seemingly became apparent to the USFWS that t h ere was no credib le scie ntific eviden ce to link any amphibian developmental abnormalities or deform ities seen in the field with exposures to metho p rene associated with operational mosq uito control, and th is unnecessa ry restri ction was rescin ded. As I probably don't have to tell you or others in your state agency (if you're familiar wi th the scientific li terature about these matters), several other much more proba b le causes of amphibian deve lopmental abnormalities have now been scientifically identified ( e.g ., parasitic infections, excessive UV light exposure, etc.) and beenlinked as the primary culp rits for what ha s been observed for amph ibian abnormalitie s, with any linger i ng connection here to t h e use of methoprene being an un warranted, poorly-foun ded leap th at serves little purpose (b ut wherever such claims still unfairly persist, then this bias c e rtainly hinders the benefici al use ofan important, environmentallycompatible mosq uito control tool). (11)

Response to Comment 1 0 . We would be interest ed in any writte n asse ssment made by the USFWS on t h is matte r. Thank you for your comme n ts.

Comment 11. Methoprene Use In Coastal Wet l ands -- As part of our statewide I n t e grated Pes tManageme n t (IPM) approach to mosq uito control, we use met h oprene (a j u venile growth-hormone mimic) as our frontline operational larvi c ide for salt marsh mosquito co ntrol, in spraying thous ands of acres of Delawar e 's coastal wetlands wi th Altosid up to several times each s u mmer (with our prima r ily us ing th e A.L.L. 20% Concentrat e formulation ) , including extensively using Altosi d on Dela w a re's two Na tional Wildlife Refuges. We find that Altosid gives us effective control achieved in practica ble manner, and to the best of our knowledge does no t have any un acceptable non-target im pacts or environmental problems.

Methoprene Use In Fres hwater Wetl ands -- We a l so use meth oprene for control of freshwater mo sq uitoes in
stormwater manage m en t basins a n d constructed wetlands, of ten using so me type of e x tended release formulation for this product in these se ttings, wh ich similar to our salt marsh use als o gives us effective control without any unacceptable side effect s. (11)

Response to Comment 1 1

. Thank you for your comments on the use of methoprene. Howev er, lacking any qualification on what is meant by “to the best of our k n owledge” or “unacce ptable side effects” we cannot make decisions on the use of methopren e based on these testimonials.

Comment 12. [My] Only comment i s on the BMP page eleven last paragr aph, with t h e sent ence t hat begins with "Metho prene can be used on older larval stag es and for ...to late to use either Bacillus or me thoprene ..."

seems to say methoprene can be us ed when its too late to use methoprene????? ?? What gives? (14)

Response to Comment 1 2 . It was a typo. Thanks for catching it. The text ha s been corr ected to read: Methoprene can be used on ol der larval stages (i.e., pupa ), and for situatio ns where it is too late to use either B a cillus thuringiensis israel ensis or Bacillus sphaericus, a mon o mol e cular fil m might be used.

Comment 13. Stat emen t in the draft : “Ecology proposes to continue to restrict the a r eas of application of methoprene." But then ecology goes on to say, "t hey will initiate a monitoring strategy to document

Best Mana g e ment Practi ces for Mosq uito Control C-9 Washington State Depar t ment of Eco l ogyconcentration levels and if necessary, levels of toxicity to non-target species.” The objective of monitoring will be to provide data o nmethoprene f o r permit re newal in 2006. Response: This monit o ring, should it take place, SHOULD ta ke place in the areas in q u estion that are he althy f r og environ m ents now. Not some p l ace that is already stressed for some other reason. And in monitori ng the areas in question there will be rec o rds of methoprene application over the past years that will gi ve some basis on where to start. And not take another twenty ye ars in anot h er location esta blishing a track reco rd. And if monitoring is going to be done then it would seem that applications of met h oprene sho u ld take place. Otherwise, whatis go ing to be monitored? (15)

Response to Comment 1 3

. Comment noted. We will take your commen ts into consideration as we devel o p the monitoring plan.

Comment 14. Calling your attention to the California draft fact sheet, written by the California State DOE, page 7, par 4, "USEPA has concluded that , use d in mosq uito control programs, met h oprene doe s not pose unreasonable risks to wildlife or the environment." Now granted, e a ch st ate can say a n d do wha t e v er they want. And i t is certain C a lifornia has endang ered specie s. But decisions being made i nCalifornia are made on sound, current research. (15)

Response to Comment 1 4

. Decisions made in Calif ornia a re revi e wed f or r e lev a ncy to our progra m. Their control operation s an d monitoring results will be included in our SEPA ev aluation.

Comment 15. It was sta t ed in the [WDFW] comments, "th e re are studies tha t h a ve found developmental effects to am phibians when methopr e ne wa s app lied at mosquito control treatmentlevels and the r e are studies that have no t observed this." Response: Those s t udies that showed neg a tive effects should be produced for review in this decision making process. And t h e studies must be the most curren t up to date studies. And not studies that are old and have been d i sproved. At the m eetin g in Olympia on 5 Marc h '04, indust ry presented
, once again, t h e current facts on me t h oprene. With even newer studies done by OSU. And WSF W said, "we still have questions." When asked what are your question s the reply was, "we don't know." However, at least after three y e ars WSFW and DOE ar e listening t o the mosq uito districts when t h ey s a y, met h oprene canno t be found or monitored for; only the effe cts can be m o nitored. (15) Response to Comment 1 5

. See respon se to Co mme n t 2. The SEPA eval uatio n and monito ring plan for methopren e have been pro p osed to clear up some of t h ese ambiguit ies rega r di ng the developmental toxicity of methopr e ne to non-ta rget species.

Comment 16. The mo strecent information is from Oregon, where pond s have been treated with methoprene and he avily monitored for the past s e veral years. In ov er ten prior years of methoprene application and close inspection of population s, there has b een no evidence of malformations. A recent discovery of infected snail populations, which harbor the deformity-causing tremat ode s , was a pre m onition of a deformity outbreak and further confirms that trematodes are to be strong ly linked with the s e def o rmities, not methopren e . The

newnes s of t h is informat ion is encouraging and i s a close geographic exa m ple of how deformities in the amphibian population are not relat e d to met h oprene. This should be taken into consideration as the BMP is revised another time. (19)

Response to Comment 1 6

. Ecology w o uld be intere sted in revie wing the Oreg on studies. Please fo rw ar d any contact information you may have.

C-10 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyComment 17 . If t h e proposed meth oprene restriction is rela ted to a nab sence of lon g -term testi n g and environmental impact studies, Well ma rk req u es ts to review the documentation t hat Washington is using for the long-ter m studies o nother larvic ide and ad ulticides products. (19)

Response to Comment 1 7 . Please see respons e to C o mment 2.

Comment 18 . As mentioned in the meeting, many mosquito districts are influenced by decisions from other parts of the nation whe n it comes to restrictions on products. If the best manage m en t practices document continues to have restrictive language for metho p rene, we will want a complete explanation for the decision so that ot her st ates can hav e a thorough understan d ing of Washington’s position - how it is solely related to Washington State e n dangered species issues and no t for the u s e of methoprene in general. (19)

Response to Comment 1 8 . Ecology’s restriction of methopren e is solely rel ate dto Washington state endangered species issues and no t for the use o f

methoprene in general. G e neral us e is not rest ricted beyond the FIFRA label. Pree mptive use of biocides, including methoprene, is rec ommended in the BMP to minimiz e mo squi to breedi n g sites and the need to us e

mor e toxic insecticides in the event of a disease outbr eak. Further , Ecology did not ass ess the harm posed b ymethoprene to endangered species sufficient to warr ant rest ricted use when a human health threat exists. Also see response to Comment 2.

Comment 19 . To date, t h e comment s that we have reviewed and tho s e t hat h a ve been previously missing ar e overwhelmingly in met h oprene’s fa vor, subm itted by professionals who have used t h e products for many, many ye ars without environmental incident. Why is ther e no impact, reduction or d e letion of the restriction language, or are thes e comments to be ignored? (19)

Response to Comment 1 9 . Our respo n ses largely a ddress those c o mments thatare bas e d in fact or law. T h e preponderanc e of user s of a p esticide does not constitu te its lack of a dverse effects because often t imes the cau ses of adver s e effects and correlati o ns are difficult and costly to determine. Also see response to Comment 2

.

Larvicide Preferences

Comment 20. After reviewing the B M P I would like to state t hat I believe thatmany improvements h a ve been made a n d it is now a mo re concise and user friendly guide. I commend you for taking out the larvicide hierarchy wording that was present before. I believe that there is still a preference indicated, but an effort has been made to clarify that a particular larvicide will not wor k best (or at all) in certai n situations. (6, 7, 8, 9, 10, 13)

Response to Comment 2 0

. We agree. The language has been further cl arified. Permit Con d ition S1.A.4 now reads:
4. Authorized p esticides are: 3⁄4 Bacillus thuringiensis israelensis (Bti) 3⁄4 Bacillus sphaericus (H-5a5 b) 3⁄4 Methoprene Granula r , Liquid, Pellet, or Briquette.* 3⁄4 Monomolecul ar Surface Fil m s 3⁄4 Paraffinic white mineral oi l. Paraffinic white mineral oil shall not be used in waters of the state unle ss:

a. The mosqu i to problem is de clared a public health risk; or b. The other control agent s would be or are kn own to be ineffective at a specific treat ment sit e ; and

Best Mana g e ment Practi ces for Mosq uito Control C-11 Washington State Depar t ment of Eco l ogyc. The water body is non-fish-bearing (consult Washi n gton State Fish and Wildlife concerning fish and wildlif e).

* Use of meth oprene is not restricted fo r use beyond the FIFRA label in more than 99% of the State. Ho weve r, methopren e is rest ricted in areas designat ed by Washington State Depart ment of Fish and Wildlife (see Appendix A) except when a health threa t exists in those ar eas a s de termin ed by state and local health departments.

Comment 21 . I have a c u rrent label of Malathion 8 Spray prod uced by Wilbur-E llis Co. with an EPA Reg. # 2935- 83-ZA. The label st ates: "Mosquito Larvae: Apply 8 fluid ozs. per acre to standing w a ter (intermittently flooded areas, stagnant water, temporary rain pools). Broadcas t use only over intermit tently flooded areas. Application may not be made around bodies of water where fish or shellfish are grown and/or harvested commercially."
I am notsay i ng that I w ant to use th is all the tim e . I a m not s a ying tha t I would use it at all. I did not use it as a larvi c ide this year, but it is registered and as long as it is, it should be left available to use at least in case of emergency without having to go t h rough all the bureaucracy that ca n occur. The more products are available the more effective, including cost effec t ive, we will be. (5, 8, 11, 12, 13) Response to Comment 2 1 . Section S1, of the permit has been re vi sed to allow the use of larv icides based on effectiveness and situation rather than j u st toxicity. A ccording to Steve Foss, P esticide Management s e ction of WSDA, larvi c ides containing the active ingredients of malathion o r temephos a r e not likely to be needed due to pesticide resis t ance or in cases of an e m e r gency. Howev er, larvicide products contai ning temephos are ne e d ed in

area s with high organic co ntent, such as wet manure fields and lagoons becaus e the other larv icides permitted for

use ar e often ineffective in these ar eas. In addition, ma nure fields a n d lagoons typically do not drain to surf ace waters. When surface wat ers are not aff e cted monitori ng will not be required. Malathion may be applied under an experimen t al use per m it , so it remain s in the tool box.

Permit Condition S1, proposed mod ification:
5. Temephos may not be u sed in lakes, s t rea ms, or the littoral zon e of wate r bodie s or on st atelisted specie sites listed in Appendix A of the BMPs, (Ecology publ ication 03-10 -023). T h e use of te mephos shall be all o wed only in highly-polluted water (i.e. tire piles) or water s with high organic content (i.e. manur e holding po nds and pastures wit h no surface water runoff), or un der either of t h e two follow i ng conditions:

a. As a re sult of consultation between the Depart ment s of Agriculture and of Ecology in response t o the development of pesticid e resis t ance o r ineffectiveness within a population of mosquito es. When temephos is applied to are as draini ng to surface water s monit oring of persi stence and re sidues are a condition of the approval. Temephos must be rotat ed with one or mor e of the a pproved alter n atives with a different mod e of action to minimiz e the development of resist ance. b. As a re sult of consultation between the Dep art ment of Health and Depart ment of Ecology in respons e to the developmen t of a human health emerge n cy as determined by the Washington State Depart ment of Healt h

. 6. Other pesticides may be applied in the context of a resea rch and development ef fort under the jurisdiction of the Washingt on State Department of Agriculture through the issuance of a Washi n gton State Experimental Use Pe rmit.

C-12 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyComment 22. In the Permit, Condition S4. A. 2. The phase, “i n the order of preference in which t h ey should be considered” should be changed to, “ m ay be cons idered.” (7, 8)

Response to Comment 2 2

. Agreed. The Permit no w state s : S4.A. 2. The IPMP shall consider the a pproved list of pesticide-based controls f o und in Section S1.

Comment 23. Pag e 9 of the Permit, Condition S4. A. 1. cont ains the phrase, “ e x c ept in response to documented” should be replaced with “to minim i ze the”

. Re sistance is v e ry difficult to document. Resista n ce manage m en t is part of a neffective IPM plan. (7, 8)

Response to Comment 2 3 . Ecology m e t with WSDA over this language because resistance i s difficult to document. The Permit la nguage now s t ates:
S4.A.1. In the IPMP, pesticides that are effecti v e in co ntrolling the mosquito population and have the least adverse impa cts to nontar get species shall be used except in response to documented development of r esist ance or in cases of ine ffectiveness o r in a declare d public health emergency.

Bio-controls

Comment 24. Use of Appropriate Bio-controls (p. 2 of the BMP) state s , “Stock wate r gardens th at have no surface inlet or outletwith mosq uito-eating fish ( i. e. , goldfish, mud minnow, stickleb ack, and perch). Tadpoles, dragonfly larvae, diving beetles, back swimmers , and fron t s w immers also prey on mosq uito la rvae. For more information, see http:// www.wa.go v /wdfw/factshts/wes t n ilevirus.htm ”

*This website has ch ang ed: http://www.wdfw .wa.gov/factshts/w estnilevirus.htm , is the current site address. However, at thi s website, it only mentions birds and bats as natu r al predators for mosq uitoes. I do not question the idea that the animal s that you listed will feed upon mosquitoes (larvae or adult), but I think it is extremely misleading to imply th a t efficient control can be achieved with organism s like birds, bats, tadpoles, diving beetles, etc. More importantly, the we bsite you are asking people to go does notappear to back up the limited clai m for bird a n d bat control with any scientific evi d ence. (6)

Response to Comment 2 4

. Thank you for the updated link. Use of bio-control s may or may not yield sufficient control, efficacy was not meant to be implied. Of concern is that goldfish and other predacious bio-controls may escape into natural w a ter bodies where they could be come invasiv e or proble ma tic.

Comment 25. In mosq uito control plans put tog e ther by several other st ates, pe sticides are liste d and identified as biopesticides or traditio nal chemical pesticides. The benefi ts and limita t ions of eachproduct are described. The applicator is free to choose the b e st fit for th e situation. The EPA classifies Bti, B a cillus sphaericus , and methopr e ne all as bi opesticides, thus puttingthem in the same cat e gory. Washington is the only state th at separat e s out methoprene. When d e ciding wh ich control agent to use, it is important to consider efficacy. “Methoprene has consiste ntly proved t o be one of t h e most effe ctive insect growth regulators again s t mosq uitoes and is usually more efficacious than biologic al control agents ” (Glare, 19 9 9 ). The pres ence of pollutants, s a linity, organic and inorganic partic l e s can all reduce the efficacy of Bti.

According to the Center for Disease Control (CDC), two fact ors that cont ribute to the spread of West Nile Virus (WNV) include abundance of vect oring species of mos q uitoes and wide spread irrigation. Washington has both. The proposed BMPs do not follow CDC guidelin es for mosquito control. The CDC r e commends the use of larvi c ides in targeted locations in risk category one. The proposed BM Ps wait until risk cat e gory four t o

Best Mana g e ment Practi ces for Mosq uito Control C-13 Washington State Depar t ment of Eco l ogyrecommend larvicide us e. By this st age, the CDC has already recommended increase d larval control and intensifying adult mosq uito control. (7, 3, 6, 8, 1 1 , 12 , 13 , 19)

Response to Comment 2 5

. We agree that bio-chemicals like the bacteria Bti an d the growth horm on e met h oprene shou ld be included i n this category. The follo wing language has been a dded to this section (p. 3) o f

the BMP to encourage preemptive chemical bio-controls where pred ators alo n e may not b e effective.

Minimization Actions

Use Approp riate Bio

- Co ntrols

3⁄4 Selective bio-pesticides such as Bac illus thuringiensis israelen sis ( B ti), B. sphaericus or methoprene are very effective preemptive controls when app lied in the spring to specific sources id enti fied by surveys. Amplifying and bridge vector species shoul dbe targeted (also s ee p. 11.).

Comment 26. Page 11: The title, “Chemical Controls” is misleading. Bti, Bacillus sph a ericus, and methoprene are all classified by the E P A as biopesticides. The title should reflect that this section includes biopesticide s, oils and tr aditional pesticides. (7, 8)

Response to Comment 2 6 . Agreed, the title has bee n changed to, “Microb ial, Biochemical a n d Conventional Chemical Control s.”

Comment 27. Preempti v e treatments (larvici d i ng known b r eeding sites early in the seaso n ) may reduce the need for ad ulticiding la ter. (1, 7)

Response to Comment 2 7

. Agreed, preemptive larv iciding with bio-chem icals has been added as an optio n under the breeding site minimiz a tion actions.

Adulticidin g

Comment 28. I believe that t h e s e ction giving a BMP for adultici ding is misplaced. I am unclear as to your implication of adulticiding applications needing a NP DES permit (unless you mean when directly affecting water). Also, I feel that if you admit you don’t have juri sdict i on in terrestrial appli c ations of adulticides, then indicated the Best Management Practices for them seem s inappropr i ate. This should be left up to the organization tha t ha s direct jurisdiction.

In addition, Ecology’s BMP states that there sho u ld no t be any adulticiding done unless there is a disease present. (5, 6, 9)

Response to Comment 2 8

. A large majority of wo rkshop attende es (O ctobe r 14 & 15 in Mo ses La ke and October 21 in Lacey) wante dthe adulticiding section left intact because it is an integral compo n ent of their integrated pes t manage men t approach to mosquito con t rol. Treat me nt triggers ar e left to the mosquito contr o l operat or o r the organizat ions they work for to deter m i n e. The BMP states: “Select triggers for the us e of adultici de products: Some mosquito control di stri cts recommen dusing light traps to monito r for mosquito es. For example, Adams C o un ty MD recommends that co unts of 8 to 12 mosquitoe s caught in 12 hours or a 3 adult mosquito landi n g count per minute in a r esidential ar e a triggers the need to adulticide (Thomas Ha worth, pers onal communic a tion, Nove mber 7, 2003). Some applica t ors r e comme n d adulticiding residential a r eas and uplan dareas whe r e mosquito es a re migrat ing only when there is evidenc e of mo squito -borne

C-14 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyepizootic acti vity at a level suggesting high risk of human infection

. The following are examp l es of this type of evidence: high dead bird densities; high mosquito infe ct ion rates; multiple positive mosquito s p ecies including bridge vectors; horse o r ma mmal cases i n dicating escalat ing epizoo tic transmis si on, including bridge vectors, horse o r ma mmal case s, or a human case with ev idence of epizootic activity (p. 21).”
In some in sta n ces, adulticiding can reduce or eliminat e the need to heavily apply l arvicides, can be used effe ctively with less environ mental i m pact to non-targe t s, and can be cost-effect ive. So for this best prac tices plan, some in formation on commonly used products and methods a re appropriat ely included. How e ver, si nce there have been objecti o ns to the inclusion of this section we will more clearly identify Ecology’ s regulatory jurisdiction in th o se section s. To be sure, Ecology has no intention of over-steppin g its regulato r y bounds.

Comment 29. Pag e 13 o f the BMP st ates, “Terrestrially a pplied insecticides are NOT regulated under federal
or state w a t e r pollution control laws and are not subj ect to NPDES permit conditions or requi r ements. However, in Washington State applications of ins e cticides used for adult mos q uito control, even if they are labeled for

use over w a te r, i.e., strea ms, wetlands, r i vers, lake s, ditch es, etc, must be permit ted under a Clean Wate r A c t (NPDES) permit.” *Please clarify; I am a ssuming tha t the preceding sentence is re ferring to when adulticides are used on, in or directly above water. Is thi s the int e nt of yo ur sentence or are you stating t h e regardless of use, an adulticide m u st have a N P DES permit? If the latt er is tr ue this seems to b e in direct conflict with the first sentence of section 7. If the former is true then t h is should be made clear in the BMP. (6)

Response to Comment 2 9 . The only time adulticide applications would have to be permitt e d is when they are applied, directly or indirectly, to waters of the st ate. Ecology’s Water Qual ity Program does not per m it the application of pesticides that are applied to terr estri al s i tes. Ho weve r, the italicized language has been r e mo ved because it was confusin g and most lik e l y not needed.

Comment 30 . BMP min i mum response does notconsider DOH and or CDC guidelines, which consider targeted ad ult mosq uito control by stating, “...a d ulti ciding based on su rveillanc e is an extremely important part of any i n tegrated m o sq uito managementprogram. (11)

R esponse to Commen t 30 . See Respon se to Co mme n t 5 and 9. Also, th e sect i on that discusses adulticiding describes the various tr iggers that may be appropriate.

Dipping Criteria

Comment 31. Could you clarify the dipping criteria for larv iciding storm water po nds? The 20 03 permit sa id larvicides could be applied if greater than 0.3 lar v ae/p upae per dip are found. The 2 004 BMPs sa ys 1 larva pe r 3 dips is the larvi c iding t h reshold. The 2004 per m it says that greater than 1 larva pe r 3 dips is the larvi c iding threshold. With last year's criteria 1 larvae per 3 dips mean t we could larvicide. Do we now n e e d 2 or more larvae per 4 dips to larvicide? (22)

Response to Comment 3 1 . Only 1 lar v a per 3 dips is needed.

Comment 32 . Could we state in the permit that entities that did control t h e year befo re based on their surveillance don't neces s arily have to wait for mosq uitoes to appear agai n the follow i ng seaso nbefore using control measures in thatwater body. This q u estion came up last year from King County, who identified their water bodies tha t need e d control and wanted to continue that control without having to do the surveillance all over again. I'm getting q u estions suchas "We fo und mosq uito larvae last year in this pond, can we apply th e

Best Mana g e ment Practi ces for Mosq uito Control C-15 Washington State Depar t ment of Eco l ogymosq uito dunks as a preventative me asure thi s year witho u t doing the dipping all over? Does the permit allow this?" (20)

Response to Comment 3 2 . The permit requires mo squito dunks prior to tre a t m ent unles s t h e site is inaccessible (se e respons e to co mment 33 below). Mosqui to breeding sites may ch ange and there is no need to u se larvicides if no larvae ar e present

.

Comment 33. Pag e C-5 - Other references use 1 per 3 dips rather tha n0. 3 per dip. (3, 13)

Response to 33. Agreed. Section S4.B of the permitnow stat es: “Pesticide applications shall not co mmence unless su rveillance of a potential application site indicates a larva/pupa count of greater than 1 per 3 dips, or unless d ead birds, infected horse s, or adult mo squito survey s indicate the presence of vector mosquitoes when larvae counts cannot be made du e to their inac cessibility. In these case s la rviciding may be desirable or ev en neces sary without the larvae dips.”

Miscellaneous Clarificat ions

Comment 34. The following clarifications are su ggested:

Page 1 - Add - Applications of pe stic ides are also subject to the Washington Pesticide Control Act (15.58 R C W) , the Washington Pesticide App lication Act (17.21 RCW) , the General Pesticide Rules (WAC 16-22 8) , the Worker Protection Stand ard (WAC 16-233) , a nu mber of pesticide and/or county specific regulations

. Page 3 - The heading "El i minate Mosq uito Feeding Sites" does not correspond to bullets beneat h the he ading. Suggest different headi n g such as " Personal Pr otective Measures "

Page 4 - Clarify that the use of larvi c ides is one o f the Minimum BMP Responses to Minimize Mosquito Breeding and use of adulticides.

Page 5 - Amend Risk Assessme nt: Probability of outbreak in humans: Re mote to low; areas with limited or sporadic W N V epizootic activity in bi rds and/or mosquitoes.

Page 10. IV. Mosquito Control Treatments Use larvi c id es at specific locations when WN V epizootic acti vity is foun d in birds and/or
mosq uitoes.

Page 11 - Amend heading to Microbial, Bioc hemical and Conventional Chemical Controls. Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (H-5a5b) are m i crobial pesticides. Methoprene is a biochemical pesticide. Monomolec u lar sur f ace films, paraffinic white mineral oil, and temephos are conventional chemical pesticides.

Page 12 - Amend web p a ge referenc e to guide of larvi c ide pr oducts. For a guide to larvicides see t h e WSDA website: http://ww w .kellysolutions.com/WA/showp roductsbypest2.asp?Pest_ID=IOAMAAC04

.

C-16 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyPage 13 - Cl arify insecticides listed in table 3 ar e for larvae control and n o t adulticides. (3, 13)

Response to Comment 3 4 : All the co mments we re accepted and chang es made to the BMP document except the WSDA web site addr ess. The WSDA w e b site was not inclu d ed beca use larvicides not permitted for use under this permit may be listed there a n d it would be confusing to list products not permitt e d for use.

Comment 35. Pag e 1 2 o f the BMP s t ates, “ Fish and game specialists and natur al resources biologists (WDFW) must be notified of planned control measures w h enev er delicate ecosyst e ms could be harmed by mosq uito control practices.... Could you please clarify how to determine a “delicate ecosystem?” Is this a legal description? Is this only WDFW land? Clarification would be helpful. (6)

Response to Comment 3 5

. “Delicate ecosyste m s” are thos e thatca n only survive under a narro w range of environment al conditions including light, salinity, temp er ature, water qu ality, and nutrients, and are ex tremely vulnerable to anthropogeni c activities. An airplane f l ying over nesting grounds demonst rat es this sensiti vity. The phrase was not us ed as legal ter m i n ology, but as plain English.

Comment 36 . The fact t hat it t a kes 38 days to obtain a license and permi t to undertake mosquito control activities would likely inhibi t a community to a ddress an e m ergency h e alth issue

... (11)

Response to Comment 3 6 . The vast majo rity of permitted entiti es in Washin gton come un der the Depar t ment of Health’s coverage by contracting with t h em. It takes about a seven -day turn aroundto do that, largely because of mailing time constr ai ns. It’s conceivable to have the turnarou nd time reduced to a day or two in a real eme r gency.

Comment 37 . Education of the public in the areas of mosqui to habitat reduction and personal protection in and of itself is not protecting the public from dise as e as is imp lied in the d r aft document. (11)

Response to Comment 3 7 . Personal protection is th e best precaut i on anyone ca n take to en s u re minimal exposure to mosquito b o rne diseases. If a person trie s to kill every mosquito in a two- mile sq uare area they will p robably not succeed and when they leave that area they are e xp osed to increas ed risk ag ain. The best insurance an yone has agai nst mosquit o borne disea se is to eliminat e the chance of exposure in thei r direct personal sp ace. This is why Appendix B, Insect Repellent Us e and Safety from the C e nt er for Dise ase Control has been added to the document. It is an excellent informational source.

Comment 38 . An important compo n ent of t h e CDC guidelines is to incl ude monitoring for the disease as well as monitoring for mosq uito populations. (11)

Response to Comment 3 8 . The Washington State Depart ment of Health is t h e lead on mo nitoring for t h e disease. Section II of the BMP directs mo squito control agent s to thei r local health departments fo r que s tions and iss u es rela t ed to monito ring for the disease.

Comment 39. Whatis g o ing to constitute monitoring? Record keeping or actual testin g? Please clarify. (5)

Response to Comment 3 9

. When the permit w as is sued, monito r i ng was inten d ed to exami n e persistenc e of the insecticides used in Washington State. Since persiste n ce da ta for t h e larvicides allowed for u se alr eady exists, possible adverse affect s to non-ta rget organis ms, rather than persist ence, wi ll be monitor e d

. Additionally, the arrival of the West Nile virus in Washington State, has re s u lted in many lo cal governments and o thers new t o mosquito con t rol practices applying larvicides during the spring and summer months. These new control operations will result in a sh arp increase in the amoun t of larvicide being applied to waters. F or these reasons, the monit oring requirement will be modified to

Best Mana g e ment Practi ces for Mosq uito Control C-17 Washington State Depar t ment of Eco l ogyonly require reporting the type, location, and quantities of l arvicides used. Ecology will use this information to prepare a plan to monit or for pos s ible adverse affec t s in area s tar g eted by the re porting resu lts.

Comment 40. We treat hundreds if not thousan d s of small po nds through out the s e ason, many of which are less than one acre. If we report those small ponds as <1 ac re our rate per acre will al l off. My district tries to record each treatment whether 10 ac res or .03 acre. (5)

Response to Comment 4 0 . Reporting in tenths or hundredths of an acre is mo re accurate a n d can be done on the current repo r ting form. We allow per m i ttees to also ‘ c lump’ the acreage they tre a t in an are a so if they trea t ten small ponds that ar e .10 acre each, they can re p ort it as one acre. This wo rks s o long as the ponds all drain to the same r e ceiving water.

Comment 41. Comment to draft: B y adding the WSDA RC Ws and WACs it would seem t hat now mosquit o control operations are u n der FIFRA and federal l a bel require m ents and NOT second level gover n ment rule making. There are so many levels of government that ALL requirements will be di ff ic ult for the home owner and laypers o n to sort o u t. (15)

Response to Comment 4 1

. Ecology m u st be respon sive to Court decisi ons. However, we a g ree and have petitioned EPA sever al times to con s i d er stre amlin ing these req ui rements for the benefit of operato rs/ applicators.

Comment 42. How will the comments be handl e d in this proc ess? It seems they are as much que s tions as
comments. Because all that h a ppens inthis process is a response is given to comme nts with no action taken

. (15)

Response to Comment 4 2

. The comments ar e revie wed for basi s in fact or law. Where inaccuracies or def i ciencies are found, they a re corr ected. Comment 43. This is the second mo dification in less than one year on the permit, how often will changes be made in the future ? (15)

Response to Comment 4 3

. This is thelast modification that will be made prior to permit renewal.

Comment 44 . I suggest adding “eco logically sensitive areas” to demarcat ed no-spray zones on ma ps (p. 11 of the BMP). ( 16)

Response to Comment 44. Agreed. The language has been added to the section: “Demarcate no-spray zo nes on maps . This may i n clud e areas such as sch ools, hospita l s, fish farm s, wildlife ref u ges, ecologically sensitive areas, the ho mes of in dividuals who are on chemically sensitive registers, an d crops grown under a certified organic progra m.”

Comment 45 . C1, Number 3, may c o ver this, but it would be nice to hav e this langu a ge in more detail somewhere. Could we put what water bodies should hav e permit cove rage? The "waters of the stat e" catc hall works to a c e rtain point, but there se ems to be co nfusion over the water bodies ( i.e. storm drains with an outlet) that could reach"waters of th e stat e." I ha ve instructed folks that i f their water body has t h e potential t o reach water s of the stat e , they need permit coverage. If "waters of the st ate" includes water bodies that have a potential to reach water s of the state, we should try to make this very cle a r. I'm still obvio u sly a little confused... (20)

C-18 Best Mana g e ment Practi ces for Mosq uito Control Washington State Depar t ment of Eco l ogyResponse to Comment 4 5 . The Department of Ecol ogy’s Aquatic Mosq uito Co ntrol permit c o vers mosqui to control activities that discharge insecti cides directly into surface wate rs of the stat e of W ashington. All who conduct mosquito control activities in wate r for communiti es, districts a n d priv ate landowners are required to o b tain coverage. "Waters of the state" includes wate r bodies that have a potential t o reach wat e r s of the state.

References cited:

Ankley, G.T., J.E. Tietge, D.L. DeFoe, K.M. Jensen, G.W. Holcombe, E.J. D u rham, and S.A. Diamond. 19 98. Effects of ultraviolet light and metho p rene on survival and development of Rana Pipiens . Environ m ental Tox i cology and Chemis try 17: 2 530- 2542

. Degitz, S.J., E.J. Durham, J.E. Tietge, P.A. Kosian, G.W. Holcombe, and G. T. Ankley. 2003. D e velopmental
tox i city of methoprene a n d several degradation products in Xenopus la evis . Aquatic Tox i cology 64: 97-1 05.

Henrick, C. A., J.K. Ko, J. Burleson, G. Lindahl. D. VanGun dy and J. Ed ge. 20 02. In vestigation of the relationship between s- methoprene and deform ities in anurans. J. of Am. Mosq . Control Assoc. 18(3): 214- 2 21.

Johnson, C

. M., L.B. Joh n son, J. Murphy and V. Beasly, Evaluation of th e potential e ffects of met h oprene an d Bti on anuran malformat i ons in Wrig ht County, MN. Natio nal Resources Research In stitute, University of Mn. NRRI technical report no. NRRI/TR-2001/ 01

La Clair, J.J., J.A. Bantle and J. Dumo nt. 1 998. Ph otoproducts and me tabolites of a common insec t growth regulator pr oduce devel o pmental deformities in Xenopus . Environmental Science and Technology 32: 145 3- 1461

. Ross, D.H, D. Judy, B. J a cobson, R. Howell. 1994 Methop rene concentrations in fre s hwater mic r ocosms treated with sustain e d-release Altosid formulations . J. of Am. Mosq . Assc. 10(2): 202-2 10.

Best Mana g e ment Practi ces for Mosq uito Control C-19 Washington State Depar t ment of Eco l ogy