North Fork Mosquito Abatement District

PesticideDischarge Management Plan

NPDES 2021






Compilation of Compliance Certification with NPDES  Pesticide Discharge Management Plan





For the North Fork Mosquito Abatement District

The Pesticide Discharge Management Plan (PDMP) Contents

A:  Pesticide Discharge Management Team 2021

Operator Names: NFMAD 2021

Mike Clawson, Operations and Field Manager

Kayden Seriani, assistant manager, tech crew/2021 crew to be determined/ Zach Hotchkiss-board member/Glenn Austin-board member/Calvin Campbell-board secretary/treasurer/DeeDee Durrance-board vice president, Rain Klepper, president.

Operator type:  application of all appropriate products, in the NFMAD boundaries covered by this permit.

Pest Management  areas and related information:

Map, site evaluation with specifics of each treatment area, data card compiling all environmental data, trapping counts, threshold levels met, product data for each specific application, are filed for each site.

The following are the Decision-makers who make up the PDMP            Team, and their contact information:

  1.  Rain Klepper, Board President (970) 201-4909, 261-9065
  2. Glenn Austin, chair Operations Committee (970) 260-4298
  3. Zach Hotchkiss, operations board member (970) 250-5542
  4. Calvin Campbell, Board member  (970-234-3032

Each Decision-maker is responsible for:

  1. Managing pests in relation to the pest management area
  2. Developing and revising the PDMP
  3. Developing, revising, and implementing corrective actions and other effluent limitation requirements.


The PDMP Team Responsibilities:

All PDMP Team members must minimize the discharge of pesticides to surface waters of the state of Colorado from the application of pesticides, and through the use of Pesticide  Management Measures.  The district will minimize the discharge of pesticides to surface waters of the State of Colorado from the application of pesticides, through the use of best Pest Management Measures.To the extent the North Fork Mosquito Abatement District determines the amount of pesticide or frequency of pesticide application, NFMAD must use only the amount of pesticide and frequency of pesticide application necessary to control the target pest, mosquito species that carry West Nile virus, and other mosquito-borne illnesses.


B:  Identification of Mosquito, Flying Insect Pest Problems

The Field manager, crew members, or Board of Director’s,  must document the following  items as required by law:

Pest Problem description with documentation including:

1. Ongoing evaluation of sites for possible physical mitigation of mosquito breeding habitat with equipment and shovel-crews, controlled burning, addition of fill dirt, or other methods to reduce standing water on public and private lands

2. A trapping perimeter, both sentinel and additional trap sites, for surveillance of adult mosquito populations. 

3.  Identification of the target pests  through trapping, identification, and counting of species

4. Rapid Analyte Measurement Protocol (RAMP) reader testing for presence of West Nile Virus in Culex Tarsalis and Pipiens species. 

5. Alteration of operations due to result on RAMP testing, including targeted adulticide application.


Action Thresholds:

For NFMAD, the thresholds have been established using historical data from the district as well as 5 districts in Utah with similar terrain, the Colorado Mosquito Control division, Alameda Cty. Mosquito Control district, and the El Paso Board of Health thresholds for Culex species. We further refined the threshold levels in concert with the Delta County Board of Public Health director, Ken Nordstrom (now retired), as well as the Colorado Dept. of Public Health.  Population density was considered with all threshold levels for all products. 

General location mapping must be included in the plan, for example, USGS quadrangle map, a portion of a city or county map, or other map, that identifies the geographic boundaries of the area to which the plan applies and location of the surface waters of the state.

For NFMAD, this has been accomplished using ARC GIS ESRI software in concert with the Delta County Mapping GIS division, providing large wall maps that meet a higher level of requirements for surveying of the district territory and all immediate boundaries. Surface waters are mapped, as well as rivers, tributaries of the rivers, ponds, lakes, irrigation ponds from mountain waters, organic and biodynamic farming locations and the springs that feed the internal waters. In 2019, NFMAD added the FieldSeeker Computer program to aid mapping of the vast 50 square miles of territory in the District. In 2020, mapping was further refined and expanded in FieldSeeker with excellent results.  This software will continue to be utilized in 2021 upcoming season. 


Water quality standards must be documented if outstanding surface waters have been impaired by a substance which is either an active ingredient or a degradate of such an active ingredient.

No such contamination or impairment of surface waters of the NFMAD has occurred.  Forms are available to document any occurrence of impairment.


  1. Identification of the Problem:  Prior to the first pesticide application covered under this permit that will result in a discharge to surface waters of the State of Colorado, and at least once each calendar year, thereafter prior to the first pesticide application for that calendar year, the operations/general manager and/or the board president will be required to submit a Compliance Certification, now known as the Annual Report,  that must do the following for each pest management area:
  1. Establish densities for larval and adult mosquito or other flying insect pest populations  OR identify environmental condition(s), either current or based on historical data, to serve as action threshold(s) for implementing Pest Management  Measures;
  2.  Identify target pest(s) to develop Pest management measures based on developmental and behavioral considerations for each pest;
  3. Identify known breeding sites for source reduction, larval control program, and habitat management;
  4. Analyze existing surveillance data to identify new or unidentified sources of mosquito or flying insect pest problems as well as sites that have recurring pest problems; and
  5. In the event there are no data for the pest management area in the past calendar year, use other data as appropriate to meet control criteria.


NFMAD has an extensive trapping program in place, using historical and current “hotspot” sites to define placement of CDC light traps, forming a perimeter around population dense areas, and recreational sites. Trap pools are then identified by numbers of each mosquito species present, using laminated photos of all stages of each species, through visual and microscopic methods.  If numbers of Culex Tarsalis, and/or Culex Pipiens meet threshold levels, a RAMP reader test for West Nile virus is run. Positive testing on RAMP triggers another level of action plan, according to stated thresholds, the Site Evaluation data for the identified problem area,  the proximity of population centers or recreational areas, plus increased search for physical mitigation of breeding and drainage sites, and habitat management. 

Negative testing on RAMP analysis may trigger the same level of action plan as a Positive test if other factors are present, such as proximity to population, high numbers of Aedes, or other nuisance species, calendar events at schools or recreational parks and areas, historical data that supports the credible suspicion of an imminent threat,  human W. Nile viral infection, or other mosquito-borne illness in the area.

Identification of primary, most common targets of NFMAD program, including life cycle, habitat, identification factors, disease potentials, and methods of control with larval products matched to terrain, is the primary method of larval control.  Identifying characteristics of each species is listed below, through all phases.  Training is conducted for field crew, and each crew member carries a loupe to magnify and correctly identify the insect observed.  Current dipping techniques are employed, and density within the site is recorded per dip, and dip count.

This PDMP is specific to the control of disease vector and nuisance mosquitoes within the North Fork district, including all species of Culicidae, in all life stages (eggs, larvae, pupae, and adults), and in all habitats in which they occur, as described below. Historically, 50 species of mosquitoes have been recorded in Colorado, of which the following are the primary targets of control efforts under this PDMP:

Culex Tarsalis

Culex Pipiens

Aedes Vexans (possible carrier of WNV and WEE, SLE) Known carrier of Heartworm for dogs and cats.

Research identification and counting of Anopheles, Culiseta, and Occhlerotatus species


 Introduction:  This mosquito can be separated from other species of the Culex genera by the median banding on the proboscis, as well as the wide basal and apical bands on each tarsal segment.  They are golden brown in color and possess a blunt rather than pointed abdomen.  Culex tarsalis are locally abundant and are persistent biters that are most active at dusk and after dark.


Life Cycle:  Females hibernate through the winter in secure locations.  In spring egg rafts containing approximately 190 eggs are laid in newly created sunlit pools that are frequently surrounded by grasses and annual vegetation.  Larvae will hatch off in 3-5 days depending on the temperature of the water, with several generations occurring throughout the summer.


Habitat:  Larvae of the Culex tarsalis tolerate a wide range of water conditions including agricultural tail waters, alkaline lake beds and fresh and saline wetlands.  Although they don’t prefer to breed in water that contains organic pollutants they are known to dwell in permanent standing water, which includes ponds, ditches, and artificial containers.


Disease:  This species of mosquito is probably the most prominent vector of arboviruses in North America.  After emergence in early spring when mosquito populations are low the females will primarily feed on birds. However, as mosquito populations rise later in the summer, bird mosquito avoidance behavior diverts many to begin feeding on small mammals, livestock, and man. This shift in hosts may account for an increase in viral transmission of West Nile Virus, Western Equine encephalitis and Saint Louis encephalitis, among many others.


Control: Due to the nature of the breeding locations this species of mosquito should be carefully monitored, and a regiment of the bacterial larvicides Bacillus thuringiensis, and Bacillus sphaericus should be applied.



Culex pipiens


Introduction:  The Culex pipiens is the most widely distributed species in the world, and can be found on every continent except Antarctica.  The adult female is golden brown and can be recognized by its blunt rather than pointed abdominal tip.  This species of mosquito has shown great skill in finding ways to get into homes where it feeds on their occupants at night.  It is for this reason that it known as the “Northern House” mosquito.  Although females of this species will also feed outdoors they prefer to shelter themselves in protected locations.


Life Cycle:  Females hibernate through the winter in protected locations such as cellars and basements.  In late spring they will lay rafts that contain several hundred eggs which will float on top of the water for 3-5 days before hatching, after this first brood several generations will occur throughout the summer.


Habitat: The larvae of Culex pipiens prefer water that contains organic pollutants. It is for this reason that they can be found breeding in such location such as catch basins, storm drains, rain barrels, ponds, and sewage treatment effluent.


Disease: This species of mosquito is a vector for many diseases including Saint Louis encephalitis, Western Equine encephalitis, Dog Heart Worm and West Nile Virus.


Control:  Due to the nature of the breeding locations this species of mosquito should be carefully monitored, and a regiment of the bacterial larvicides Bacillus thuringiensis, and Bacillus sphaericus should be applied.


Aedes vexans


Introduction:  This inland floodwater mosquito can be characterized by its distinctive physical features that give it a “warrior like” appearance.  The adults are black and brown with white and grey markings, and they possess a distinct tip at the base of their abdomen.  These tiny warriors will attack and bite ferociously, especially at dusk.  In the North Fork Valley these mosquitoes dwell in heavily irrigated pastures, as well as along the floodplains of the river bottom.


Life Cycle:  In the late fall the adult female will lay her eggs in areas that have a history of holding flood water, which are referred to as floodplains.  The eggs are laid singularly either on the ground or on dried up vegetation, and are protected with a strong exterior that keeps them safe throughout the winter.  In spring, as irrigation and rising river water are introduced to the dry floodplains, the eggs are soaked and within 3-5 days a larvae will hatch.  The Aedes vexans mosquito begins hatching early in the spring, however many generations may occur throughout the summer, with a new brood hatching about every 18-24 days dependant on flood patterns.


Habitat:  A. vexan larvae occur in a wide variety of habitats, however in the North Fork Valley it is common for this species to occur as a result of pasture irrigation.  This habitat provides a large, known flood plain and exposure to direct sunlight which accelerates that mosquito lifecycle.  Brackish waters in the river bottom often contain large numbers of A. vexans that are introduced to runoff waters via the river in the early spring.  Finally, at the base of the Bookcliffs, there are pools of water that form during runoff or heavy rains that can produce large numbers of very aggressive mosquitoes.


Disease: Mosquitoes have the ability to transmit pathogens that cause some of the worst diseases in the world.  This particular species of mosquito is no exception, as it has been shown that they transmit Western Equine Encephalitis, California Encephalitis and dog heart worm.


Control Methods: Due to the nature of the breeding locations, the insect growth regulator Altosid would be applied followed by the bacterial larvicide Bacillus thuringiensis (BTI).



Ochlerotatus dorsalis

Introduction:  The Ochlerotatus dorsalis mosquito is sometimes referred to as the ‘Pale Marsh’ mosquito due to its light coloration and its propensity to prefer areas where brackish water is present. Known for its salty personality, this mosquito is an aggressive biter that tends to bite most fiercely in early spring.  In the North Fork Valley this mosquito will be found near the river bottom, occasionally near desert water holes, and in heavy agricultural areas.


Life Cycle:  In the late Fall the adult, female, O. dorsalis, mosquito will lay her eggs in areas that have a history of holding flood water.  These areas are referred to as flood plains.  The eggs are laid singularly either on the ground or on dried up vegetation, and are protected with a strong exterior that keep them safe throughout the winter.  In spring, as irrigation and rising river water are introduced to the dry flood plains, the eggs are soaked and within 3-5 days a larvae will hatch.   While the O. dorsalis mosquito is most prominent in the spring, several generations may occur throughout the summer, a new brood hatching about every 18-24 days dependant on flood patterns.


Habitat:  O. dorsalis larvae occur in a wide variety of habitats, including both fresh and alkaline waters.  In the North Fork Valley it is common for this species to occur as a result of pasture irrigation.  This habitat provides a large, known flood plain and exposure to direct sunlight which accelerates that mosquito lifecycle.  Brackish waters in the river bottom often contain large numbers of O. dorsalis that are introduced to runoff waters via the river in the early spring.


Disease:  Mosquitoes have the ability to transmit pathogens that cause some of the worst diseases in the world.  This particular species of mosquito is no exception, as it has been shown that they transmit both California Encephalitis and dog heart worm.


Control Methods

Due to the nature of the breeding locations, the insect growth regulator Altosid would be applied, followed by the bacterial larvicide Bacillus thuringiensis (BTI).


Trapping, Identification, Counting of Mosquito Species, Analysis of Data

Mosquitoes are identified in larval stages instar 1-4, pupae, and flying adults.  Trap perimeters around the towns of Hotchkiss, Paonia, and the midway corridor along Rt. 133, are trapped, identified, and counted, once per week unless priority increases due to higher instar, presence of pupae, or landing adults while crew is observing and testing the site.

Historical areas of breeding have been compiled, analyzed, and evaluated for physical mitigation by hand or machine.  Public Works, Fire Department, Volunteer crews, and the NFMAD crew continue to work together to destroy and mitigate breeding habitat, before the use of pesticides of any type are necessary.


Mosquito surveillance is a routine part of the NFMAD control program, providing information on the numbers and species types of mosquitoes present in the district.  Mosquito surveillance pre-treatment helps direct the mitigation program of the district, and post-treatment gives information on the effectiveness of the control strategies being used, and the need for alteration of the NFMAD plan. Trapping also helps to determine priority and timing, along with visual inspection and dipping at the sites. Routine surveillance also supports identification of unknown breeding sites, for example, if a trap pool contains a large number of adults, the search for the breeding site is expanded in .25 mile increments. Successful control strategies used in the district include treatment during the mosquito life cycle, where products and physical mitigation are aimed at egg, larval, and if necessary, pupae phases, to avoid the hatching of adults whenever possible.  This decreases the usage of pesticide products significantly, which is both cost-effective, as well as environmentally a best management practice.

Larval Surveys

Most of the equipment for larval surveillance may be commonly purchased at local stores, and is a cost-effective, efficient method of mosquito control.  NFMAD performs extensive larval surveillance on sites that have historically shown breeding activity, as well as any newly reported or evaluated areas.  Larvicide programs are targeted at controlling mosquito larvae before they leave the water.  This strategy can be the most effective, most economical, and the safest method of controlling mosquito populations.  Given that one adult mosquito can increase the mosquito population by hundreds every week to ten days, depending on adult control will doom the program to failure.  Without a larval surveillance and mitigation plan that is extensive within the district, the incidence of mosquito-borne illness will inevitably rise.  Chemical control, essentially adulticide sprays, do not have the level of success that would constitute mosquito control without a larvicide program, as well as a physical mitigation effort.  Avoidance of pesticide usage by eradication of the mosquito populations earlier in the lifecycle allows NFMAD to decrease the discharge and application of pesticides into the environment.

A white plastic or metal dipper is used for collecting water from artificial and natural water sources, including ditches, margins of ponds, stagnant areas, culverts, etc., as described in Source Reduction site types, above.  Estimates of larval population densities are obtained by counting the number of larvae per dip, using a standard size dipper.  Three to five dips are taken, essentially every 10 feet around a site, noting and recording on the data card for the site, the number of dips taken, and the numbers of larvae in each dip, and the life stage of the larvae (instar 1-4), and presence of pupae. Water temperature is also recorded, and using this combination of factors, an educated estimate as to when adult mosquitoes will emerge, and hence, what control efforts should be made, in what timing.  Larvae generally develop faster in higher temperature water.  Large numbers of pupae indicate a large number of adults will emerge within a few days, signaling an urgent priority for pupae treatment to prevent the hatch.   Since pupae do not feed, larval products such as Bti that must be eaten by mosquito larvae are ineffective, and a pupacide must be added to the treatment protocol for successful mitigation.  If larvae are present in instar 1 and 2, exclusively, it may be 8-10 days before adults emerge, depending on the species and temperature, hence larval products containing Bti or Bs may be suitable.  Large numbers of pupal skins floating on the surface is a sign that adults have recently emerged, and adult control methods must be added.  Accurate identification of species is useful in determining the appropriate larval control agent. For example, Bacillus Sphaericus is highly effective on Culex mosquitoes, but not Anopheles.


Adult Surveys

Adult mosquito surveillance is an essential part of the NFMAD program of control.  Adult surveillance provides information on the effectiveness of the larvicide program.  However, the presence of some adult mosquitoes does not mean that larviciding efforts are not working as no product-based program will be totally successful in eradicating mosquitoes of all species. The objective is to control the mosquito populations as early in the life cycle as possible, while using physical mitigation techniques to search and destroy breeding habitat, improve agricultural irrigation practices, educate homeowners, and work towards community coordination to achieve eradication of mosquito habitat.  This is the only way to successfully eradicate mosquito-borne illness.

Adult surveillance involves routine trapping, identification, and counting of each species to estimate the population density and distribution, indicate the presence of breeding sites that have been overlooked or unsuccessfully mitigated at an earlier stage, and provide Culex females for West Nile virus testing using the RAMP reader system.

CDC Light traps, dry ice for C02, are employed by NFMAD.  These traps are designed to collect adult female mosquitoes that are seeking a blood meal source, attracted to carbon dioxide produced by a potential vertebrate host.  NFMAD sets these traps throughout the season, starting quite early and continuing through September, depending on weather and variables such as the irrigation season start and end dates, to collect data on mosquito relative population numbers and species diversity.  Twenty traps are set at the same locations throughout the season, at the same height, the same night of the week whenever possible, and when feasible, the same locations are used year to year.  Floater traps are set in response to nuisance reports from residents of the district, to close a perimeter around an event or recreational site, or as a “rental” to individuals that want information on their home.  Traps are set between 3pm and sunset, and are collected the following morning between sunrise and 11am.  Adult mosquitoes are then euthanized by freezing, identified to species when possible, and counted.  If threshold levels are met for Culex species, the mosquitoes are then RAMP tested for West Nile virus.  Testing results determine the next phase of treatment.

NFMAD maintains a voicemail telephone number, 970-527-6681, as a “mosquito hotline” where residents of the district can call with mosquito annoyance complaints, reports of standing water, or observance of crew behavior.  Information obtained from these calls is used to help direct trapping efforts using floater traps, and the need for evaluation of a site not currently in the database.

With new site areas, or sites without historical data for a variety of reasons, proximity to populated areas is given higher factor-weight.

In addition to trapping, NFMAD includes surveillance of possible daytime resting stations for adults, both natural and manmade.  These include houses, barns, sheds, privies, bridges, culverts, hollow trees, overhanging cliff areas, and foliage.


C. Pest Management Options Evaluation

Once each calendar year, the board president and/or field manager must select and implement efficient and effective means of Pesticide Management Measures that minimize discharges resulting from the application of pesticides to control mosquitoes or other flying insects pests.  Management measures for each area must be evaluated by the District, to include all the options listed below, including a combination of these management options, considering impact to water quality, impact to non-target organisms, feasibility, and cost effectiveness, and any relevant previous Pest management measures.  Vector-borne disease outbreaks may require changes to this PMDP, and elevation to a higher Level of Response.

When products are used, the application rate and application frequency is always as specified on the product label.

Management Options:

  1. No Action
  2. Prevention
  3. Mechanical or Physical Methods
  4. Cultural Methods
  5. Biological Control Agents
  6. Pesticides


C-1: Determination of Action or No Action:  determination of action vs. no action is dependent upon the current Response level that exists within the district, and Delta County surrounding areas contiguous with NFMAD boundaries, as well as Delta Mosquito Control District #1, and Response Level as determined by the Delta county Board of Health director and office.  Regardless of surrounding areas, if NFMAD Response Levels indicate Action within the district boundaries, efforts at coordinated communication and action plans will continue, but not delay Action initiation within the NFMAD boundaries.



The district will not conduct pesticide applications unless pest populations meet treatment thresholds, with all factors in consideration, including weather, proximity to population areas, proximity in distance and timing to calendar events at recreational areas, schools, fairgrounds, etc., historical data on site of proposed treatment, proximity to river or other outstanding waters, ownership of site and permissions, proximity to organic agriculture and/or bees, pesticide sensitivity registry, and possibility of control using physical mitigation techniques.



NFMAD surveillance and response plan is based on the federal regulations for the state of Colorado Permit 1/1/2020, hence, on conditions at three levels: Normal season, Emergency planning, and Epidemic.  Five risk factors are analyzed to determine the appropriate response level:

  1.  Environmental condition: snowfall, rainfall, temperature, previous to current season
  2.  Adult mosquito vector species, “abundance”
  3.  Viral test positives on RAMP and/or PCR
  4.  Human cases of mosquito-borne illness, including West Nile and SL Encephalitis
  5. Proximity of detected viral activity in relation to population areas

Each of these risk factors counts as 1 point, with 5 points representing conditions indicative of a high risk of human infection with a mosquito-borne virus.

Level 1: Normal Season, 1.0-2.5

-typical  snowpack, rainfall, average typical temperatures

-mosquito vector species at or below threshold

-Zero viral activity in test pools from trapping

-No human cases


Conduct public education for reducing habitat for breeding at home and personal protection

Conduct mosquito and virus surveillance activities consistent with IPM program

Conduct routine mosquito larval control, as well as continued physical mitigation

Evaluate possible pesticide resistance in vector species, research possible mutations

Ensure adequate emergency response funding

Continue press notices and public information announcements



Level 2: Emergency Planning  2.6-4.0

-Snowpack, rainfall, weather atypical moisture conditions

-mosquito vector species greater than threshold

-One or more positive viral tests of trapped mosquito pools

-One human case in Delta County

-viral activity in close proximity to populated areas


Enhance public education, include signs and symptoms of prevalent illnesses (West Nile, SLE)

Increase surveillance and larval controls

Increase adult surveillance

Increase number of mosquito pools tested for virus

Review, update, and enact selection criteria for adulticide products.  Review candidate pesticides and current product specs for availability and susceptibility of vector species

Conduct localized chemical controls of mosquito adults, up to Phase 3 of Adulticide measures

Contact commercial applicators in anticipation of large scale treatment for adults

Review crisis public communication plan, coordinate with Public Health office.

Level 3: Epidemic,  4.1-5.0

-Snowpack, rainfall, weather,  Atypical, over longer period of time and seasons

-Adult vector populations extremely high, at top of threshold and above

-One or more human illness cases in NFMAD district

-Virus detection on testing in Delta County, regardless of population density


Conduct full scale media campaign

Initiate crisis communication plan

Continue enhanced larval surveillance and control of immature mosquitoes

Broaden geographic coverage of adult mosquito surveillance and trapping

Accelerate adult mosquito control if appropriate, consider Phase 4

Coordinate response with county Public Health office

Coordinate mosquito surveillance and control in geographic regions that border the NFMAD district.

Continue mosquito education and control programs until mosquito abundance is substantially reduced and no additional human cases of illness are detected.


Thresholds for Action vs. No Action NFMAD 2021

2021 Thresholds for Adult Mosquito Mitigation


Area with Higher Population Density:

*1-20 Culex species mosquitoes in trap:      RAMP TEST


*Go to Phase I of Adulticide protocol with targeted fogging


*Go to Phase 1 Adulticide protocol if there are human West Nile cases in area of trapping, and/or a strong, credible suspicion of infected Culex presence based on historical data.


In addition:

*Expand breeding site search, larval and pupal treatment by    .25 mile.

*Evaluate site for possible physical mitigation

*Contact immediate landowners for cooperative mitigation     effort and warning of illness possibility

*Re-trap after adulticide application to determine success of   treatment.

*Re-trap again in one week: if Culex numbers do not drop,  advance to Phase 2 of Adulticide protocol, and expand search/treatment to .50 mile, in accordance with NPDES  response level requirements.


Area with Lower Population Density:

*10 and above Culex species in trap

Same modifiers as Area of Higher Population


Total Mosquitoes, non-specified species:

*100 total count and above mosquitoes in trap:

Trigger Phase 1 Adulticide protocol due to potential for human disease.


For a Scheduled Community Event:

*Increase surveillance, including trapping, 2 weeks prior to event. *Apply Adulticide according to higher population density modifiers.

C-2:  Prevention

Primarily prevention is accomplished through education.  NFMAD maintains an extensive website (www.nfmad.org), with information for the general public, including actions they can take to avoid creating mosquito habitats in areas under their personal control, and ways to reduce the risk of contracting West Nile virus or other mosquito-borne illness. Prevention education also includes information on proper use of mosquito repellents for various age groups.  Community outreach and education continues, with the production of brochures and other informational handouts, given out at local events and available in local farm and feed stores that sell larvicides.


The North Fork Mosquito Abatement District (NFMAD) will continue to conduct source reduction and enhancement of drainage/terrain to reduce mosquito breeding sites as part of the prevention plan.  This is essential to the success of mosquito abatement, comfort for residents, and safety from mosquito-borne illness, and protection of our outstanding waters, rivers, lakes, and springs.


Prevention and education are the cornerstones of the NFMAD program, and necessary to reduce the need and usage of pesticides in general.  Cooperative efforts between the district, and private homeowners, the towns, the county, the railroads, the mines, and federal lands are an integral part of successful mitigation, and ultimate eradication, of mosquito-borne illness.


Examples of physical/mechanical methods include emptying containers holding water in residential neighborhoods, cleaning junk, tires, etc., that can hold water from land, removing animal and manmade dams such as beaver dams, draining water from irrigated fields, opening drainage ditches using hand tools or backhoe, controlling irrigation tail water.


Site evaluation forms the basis of preventive measures.  Below are the instructions for NFMAD’s Site Evaluation Form, completed for every site that may require physical and/or chemical mitigation for mosquitoes.

Source Reduction is the most effective mosquito control in current use, and creates success without the use of pesticides, hence less issues with discharge to the surface waters of Colorado.


Definitions of Source Types:

Canal:  large ditch with flood control gate

CatchBasin:  Basins used to collect and direct runoff water. Found in streets, parking lots, and sometimes, private driveways.

Large container:  over 100 gallons

Small container:  holding less than 100 gallons, such as urns, trough, buckets, flower pots, etc.

Creek: Creeks, streams, and potholes, naturally formed

Ditch:  roadside, railway, and other manmade, longer runs of excavation

Gutter: usually in the street, where water accumulates

Marsh:  shallow marshy areas, low areas

Natural pond:  lakes and ponds, including stock, duck, and gravel pits

Ornamental pond:  fish ponds, water garden, fountains, pots, tubs

Overwatering:  pooled water

Rainwater:  places collecting storm water, puddles, fields, etc.

Sanitary sewers:  sewer ponds, cesspools, sewer lines, septic tanks.

Seepage:  natural springs, ground water

Spa:  spa or hot tub

Stormdrain:  pipe or culvert carrying storm water

Swimming pools:  obvious!

Tires: tire storage and disposal site

Treehole:  cavity in a tree holding water

Instructions for Site Evaluation Sheet


Grid Sector:  from District Map/ Site #:  Is this a new site?  If so, assign a number.  Revised?  Historical hotspot?  Deleted?  Reassigned a number?

Site Type:  Same list as the data cards:

Roadside, Field, RailRoad, Private Home, Irrigation Ditch, Culvert, Cattails, Swamp, Bog, Marsh, Pond, Wetland, Conservation Easement, River Front, Recreation/Park, Misc. Backyard features, Riparian, County, Town, etc., same list of site types on data card instructions.

Site Factors:   Organic Farm, Bees, Chemical Sensitivity/No Spray Registry, Conservation easement, wetlands, endangered species area, protected bird rookery, or other designation that would influence physical and chemical mitigation efforts.

Priority:  Low/Medium/High/Urgent and Immediate

Physical mitigation possible by hand or machine?  Is it possible to get a piece of equipment to the mitigation site?  By hand, one man or two? A crew?  Would the area be cleared with a controlled burn?

Possible Causes:  Trace the issue whenever possible to locate the source of the problems.  Basically, this is finding the impediment to the flow of water.  For example:

Irrigation tailwater?  Irrigation overflow?  Pond overflow or seep?  Fingers of water coming off river or pond?  Is there a blockage, such as a beaver dam, manmade obstruction, junk, plastic, etc. in the drainage area?  Blocked culvert?  Is the flow of water blocked by vegetation, cattails, or other organic matter?  Willows?

Most causal chains involve more than one of these factors, and following the fall lines of water will give the best information on possible mitigation. Under possible causes, please include the owner, if known, of each site area, such as the county, a town, a private home, a renter, etc.

Comments/Physical Treatment:

What is the condition of the site?

Dense foliage, or other cover that would interfere with treatment?

Size of area to be treated?

Is there work to be done before treatment would be effective, or possible?

Would burning help?

Can the outflow and movement of water be improved with physical mitigation by hand or machine?

Will the level of mitigation eradicate the site, or will it need to be updated and kept under surveillance during the mosquito season? Has this site had treatment and/or physical mitigation in the past seasons? Is there anything that can be added that will permanently fix the site, or will this continue to be an ongoing problem area?

Special notes on directions, access, gate combinations, dogs or other animals, parking?


C-3:  Mechanical /Physical Methods


The district will use all physical and mechanical methods available, both by paid crew and volunteers, to reduce mosquito breeding sites where possible with permission of property owners, either private or public, with the purpose of reducing pesticide usage.  All mechanical and physical methods of mitigation and reduction of breeding sites in the NFMAD area are based on site evaluation and remediation planning.  See above, C-2: Prevention, for details of site evaluation and examples of mechanical and physical mitigation.


Source reduction is focused on the mitigation of mosquito-breeding habitat. Mosquitoes in Colorado occur in a wide range of habitats and larvae are found at nearly every elevation wherever water occurs.  Many mosquito larvae occur in man-made environments, as a result of agricultural  irrigation practices, drainage issues with irrigation tail water, containers around buildings, junk and debris that catch water, pond seepage, depressions from uprooted foliage and trees, hoof prints from livestock,  etc., as well as urbanization of natural environments.


Ditches and irrigation canals are prevalent in the NFMAD.  These structures are often cited as sources of mosquito problems by the general public, however, it is primarily the pooling and seepage along these ditches that often result in more significant larval habitats rather than the canals.  When the flow is discontinuous, pools left behind in drying irrigation canals, also can become significant sources of nuisance species, especially Aedes.


Livestock pastures can pose a serious problem to the Mosquito Abatement district as the livestock not only provide a reliable blood meal for female mosquitoes, but form numerous isolated larval habitats from their hoof prints.  Livestock dung also adds nutrients to the water for species that need highly organic conditions for survival.  Over-irrigation of pastures and hay fields can also create perfect temporary conditions for mosquito larvae. For the NFMAD area, these fields primarily host Aedes species, although if the water persists due to aggressive irrigation or weather factors, even a short time, Culex can also lay eggs and eventually hatch from these conditions.


Crop Agriculture practices result in a wide variety of water features associated with tilling and watering the soil. This includes agricultural holding ponds for temporarily storing irrigation water, crop row furrows that temporarily retain irrigation or precipitation water, and field tail waters that collect run-off water from the irrigated field, or precipitation.


Human-modified drainages consist primarily of existing streams and riparian areas that have been altered to restrict flow, reclaim land, or to intentionally create new wetlands for wildlife habitat by including extensive marshes with emergent vegetation.  Species commonly encountered in these drainages include Aedes Vexans and Dorsalis.  Culex Tarsalis also may be common when weather conditions result in water persisting longer.


Gravel quarry lakes have existed in the North Fork district, but most hold water permanently and support fish populations and other mosquito predators.  However, some include shallow vegetated edges, and cattail marshes, which can be significant sources of Culex tarsalis and other related Culex species.


Detention and retention ponds, that primarily serve to collect and store storm water temporarily (detention), or permanently (retention), are not mosquito breeding issues unless there is flood waters or the pond is not designed to drain completely.  Aedes are fast-developing and can go through entire cycle of stages to flying adults quickly.  If the water persists, Culex can develop.


Ornamental ponds are intentionally filled with water, usually for aesthetic purposes but also as landscape boundary features, recreational waters such as fish ponds, etc., occur on private and municipal properties, including yards and parks.  Culex species will inhabit shallow side-waters with emergent vegetation (cattails, sedges, etc) where predators such as fish are unable to access the larvae. If the water levels fluctuate significantly, these ponds can also become a source for floodwater types of Aedes, as water levels reach eggs laid along the shore.


Storm drains and catch basins are found in the towns and outer residential areas, and when not maintained or blocked, can hold water long enough to be a habitat for Culex Pipiens, an important vector for W. Nile virus.


Containers come in all sorts of shapes and sizes, and may be as small as a bird bath or a flower pot, or as large as a discarded boat or abandoned swimming pool.  Containers are the primary larval site for Culex Pipiens, and are difficult to control since most likely containers will be on private land.

C-4:  Cultural Methods


NFMAD will continue to work with private residential property owners, farmers and ranchers, township properties, and county properties, to conduct proper water management with the purpose of reducing pesticide usage.  Examples of cultural methods of mitigation include allowing irrigated fields to dry down within 5 days, opening drainage to allow irrigation water to return to the river rather than becoming standing puddles, and pasturing livestock in a manner that reduces hoof prints holding water.



C-5:  Biological Control Agents


NFMAD uses biological control agents, such as Bti, Bs, and predator species such as fish, whenever feasible. Larviciding is a general term for the process of killing mosquitoes by applying natural agents or commercial products, designed to control larvae and pupae.


Larvae Threshold Levels

Larval control methods are applied, one or more, for any site where an average per dip count is greater than one larva or one pupa detected by visual inspection of a series of dips at the site.  Treatment is then necessitated only in those areas of the site where larvae or pupae are present, or where conditions are such that they would be expected to occur.  Prophylactic measures may also be taken at sites where high levels of larval production are historically known to occur, or can be reliably predicted, utilizing primarily long-duration methods, including physical controls such as site-modification, biological controls using fish or other predators, or long-duration biological pesticide control products.



Bti:  the primary biological control methods used in the NFMAD include formulations containing Bti, an environmentally responsible bio-larvicide derived  from Bacillus thuringiensis israeliensis, a naturally occurring spore and crystal-forming soil bacterium.  The active ingredient in Bti is a crystalline delta-endotoxin.  Mosquito larvae are killed  through the ingestion of the delta-endotoxin, which reacts with the stomach secretions and causes gut paralysis and death.  Bti is the most widely used mosquito larvicide in the United States of America.  The safety of Bti was determined by extensive toxicological testing before approval for use.  Research and field trials have shown that Bti has no toxic effects on beneficial and predacious arthropods or on aquatic vertebrates.

Natural predators:  such as fish…in the past mosquito fish (Gambusia affinis) was introduced in some situations to reduce mosquito populations, but their use has now been prohibited by the Colorado Parks and Wildlife agency.  Alternatively, the fathead minnow (Pimephales promelas) is a native predator that is useful for control in smaller ponds

Aquabac  (Vectobac, aka)

Short Description:

AQUABAC® is a biological larvicide used to control mosquito larvae and black fly larve in aquatic habitats. AQUABAC is based on the naturally occurring soil bacteria, Bacillus thuringiensis israelensis (Bti). This highly effective and economical microbial insecticide can be used in nearly all aquatic habitats, to effectively and efficiently control target species in the larval stage.

Active Ingredient:

Bacillus thuringiensis subspecies israelensis

Mode of Action:

Bacillus thuringiensis subspecies israelensis is specific to mosquitoes and black flies due to the reaction in their high PH mid-gut. Bti spores contained within a crystal, known as a delta endotoxin, only activate in a highly basic digestive tract such as those specific to mosquitoes and black flies. When AQUABAC is ingested by a mosquito or black fly larvae, the Bacillus thuringiensis subspecies israelensis act as a stomach poison. The mid-gut of the mosquito or black fly larvae is broken down, eventually resulting in paralysis and death of the larvae. Bti is target specific and does not adversely affect wildlife or beneficial insects, humans or pets.

Where/When to use:

AQUABAC can be used in any habitat which supports mosquito or black fly larvae. Common appropriate mosquito habitats include, but are not limited to woodland pools, roadside ditches, tree holes, temporary pools, artificial containers, and floodplains. To target black flies, AQUABAC is applied to production areas of rivers and streams. AQUABAC must be applied when mosquito or black fly larvae are present and in a feeding life stage, the active ingredient in AQUABAC must be ingested by the larvae, no contact effects.

Formulations/Packaging: Name changed to Vectobac in 2020

  • AQUABAC 200 G/CG 10/14 Mesh Granule is available in 40 lb bag and 1,000 lb bag.
  • AQUABAC 200 G/CG 5/8 Mesh Granule is available in 40 lb bag and 1,000 lb bag.
  • AQUABAC 400 G is available in 40 lb bag.
  • AQUABAC 400 DG Lite is available in 50 lb bag.
  • AQUABAC Primary Powder is available in 100 lb dr.
  • AQUABAC XT liquid is available in 2X2.5 gl case, 30 gl dr, and 250 gl tote.



  • Bti is a species specific microbial agent; it does not interrupt the normal functioning of other beneficial species and predator.
  • Bti can be applied to almost any aquatic habitat without environmental impact concerns.
  • Bti is highly effective and due to its mode of action there is little chance mosquitoes will build resistance.
  • 400G has twice the potency of all other Bti formulations on the market allowing treatment of significantly more acres with less product, by air or ground.1


Becker Microbial Products

Bsph:  Like Bti, Bacillus sphaericus (Bsph) is also a naturally occurring soil bacteria with mosquito larvicidal properties.  Additionally Bsph has the favorable property of a longer persistence in nature and the ability to release fresh spores into the water column and to recycle itself.  This recycling offers an extended residual control of newly hatched mosquito larvae.  Bsph contains toxic protein crystals and living spores which larvae feed on.  In the larvae’s gut, enzymes dissolve the crystals into smaller crystals called protoxins.  The protoxins almost immediately begin to paralyze the gut and within a few hours break through pores in the gut wall and invade the body cavity where they begin to multiply.  The mosquito larvae will die within two days.  Bsph is utilized in more permanent or long-term waters, where mosquitoes, especially vector Culex species, will continue to lay eggs in the water, such that a longer residual product is useful.

VectoLex/Spherotax:  Bsph product:

Short Description:

VECTOLEX® (also known as Spherotax) is a biological larvicide and provides selective, environmentally sound control of most mosquito larvae. VECTOLEX is based on Bacillus sphaericus a naturally occurring bacturim in the environment. These fast-acting products are commonly used in municipal and industrial water treatment facilities, animal waste lagoons, storm sewer catch basins, continuously irrigated croplands and pasture, and mosquito breeding sites. VECTOLEX offers effective residual control of a number of mosquito species.

Active Ingredient:

Bacillus sphaericus (Bs)

Mode of Action:

The larvae ingest the insecticide, consisting of Bs spores produced by the bacteria. Only when activated by the larva’s specific gut PH and enzymes, do the spores become toxic, causing damage to the gut of the mosquito. Mortality rate is dependent on consumption of the Bs by 1st through early 4th instar larvae. The product is quick acting and highly effective against a number of mosquito species and its long term residual makes it ideal for use in a wide number of permanent aquatic habitats.

Where/When to use:

VECTOLEX may be applied to any water sites except treated, finished drinking water reservoirs or drinking water receptacles. VECTOLEX is primarily designed for permanent water habitats and intermittently flooded sites that stay wet long enough for production of additional broads.


  • VECTOLEX CG and FG are available in 40 lb bags
  • VECTOLEX WDG is available in 24×1 lb containers and 25 lb dr
  • VECTOLEX WSP is available in cases of 800 water soluble packets



  • Because of the products specificity it has little effect on plants, fish, or other organisms that live in the water.
  • The toxins in Bs are target specific and will not affect pets, humans, birds, fish and other non-target organisms.
  • Provides long term residual control of mosquito larvae



Valent BioSciences

Altosid: Another biological control used by NFMAD is Altosid, methoprene, which is a hormonal insect growth regulator (IGR). Methoprene disrupts normal mosquito development and metamorphosis, preventing the emergence of breeding, biting adult mosquitoes.  Altosid briquettes, pellets, granular and liquid formulations, have a long residual duration, but are expensive and are also not specific to mosquitoes only, such that other insects exposed to it may be unable to complete their metamorphosis.  Therefore, this control method is only used in limited situations, including abandoned swimming pools, ornamental ponds, fountains, cisterns, and similar situations where non-target insects are not an issue, and where the likelihood of continual mosquito production makes a long-duration residual product more cost-effective is useful.

Short Description:

ALTOSID® is a larvicide that disrupts the normal growth pattern of immature mosquitoes in water and prevents them from becoming breeding, biting adults. ALTOSID is an easy to use, long-term, cost-effective and environmentally responsible mosquito control larvicide.

Active Ingredient:


Mode of Action:

All ALTOSID formulations contain the Insect Growth Regulator, (s)-Methoprene, which interferes with a mosquito’s normal metamorphosis. (S)-Methoprene in ALTOSID products has the industry’s lowest toxicity rating. ALTOSID naturally degrades in the environment and will not adversely affect humans, fish, waterfowl, mammals or beneficial insects, thus it can be used in your program’s most sensitive areas. And you’ll feel even better about the effective, long-term control you’ll get in return. Furthermore, residual larvicidal activity reduces adult populations and the need for using adulticides.

No two mosquito habitats are alike – and neither are the ways you treat them. That’s why there are a variety of ALTOSID formulations. Each provides the extended control you need in easy-to-access or difficult-to-treat areas. ALTOSID formulations are labeled for use in known fish habitats. ALTOSID offers the most diverse product line of all larviciding products, and can effectively prevent the emergence of breeding, biting adults without upsetting the food chain or impacting non-target species. So you’re ensured consistent control – and peace of mind.

Where/When to use:

ALTOSID Briquets are designed to control mosquitoes in small bodies of water such as catch basins, ponds, lakes, ditches.

ALTOSID Liquid Larvicide SR-5 & Liquid Concentrate SR-20 may be applied to areas when flooding may result in floodwater mosquito hatch. It may also be applied to irrigated croplands after flooding to control mosquito emergence.

ALTOSID XR-G may be applied to temporary and permanent sites that support mosquito larval development with multi-broad potential.

ALTOSID SBG is ideally suited for short-term (five to seven days) control of mosquitoes.

ALTOSID WSP release effective levels of ALTOSID Insect Growth Regulator for up to 30 days under typical environmental conditions for treatment in abandoned swimming pools, catch basins, storm drains etc.

ALTOSID PELLETS provide a slow dissolving, extended residual for up to 30 days making it extremely cost effective for sites like rice fields, cattail marshes, abandoned tires or other man-made habitats. Can be applied up to 15 days before flooding.

ALTOSID PRO-G is an easy to apply granules. Altosid Pro G releases effective levels of Altosid insect growth regulator for up to 30 days after application. Applications should be continued throughout the season to maintain adequate control.



  • Kills all mosquito pest species.
  • Consistent results in all populations/densities.
  • No impact on food web.
  • Labor savings with extended residual.
  • Multiple formulations to meet application and economic requirements.
  • Pretreatment capabilities
  • Excellent canopy penetration


Central Life Sciences

Barrier Spray:  Mavrik by ADAPCO

Barrier Spray:  BVA 13

Short Description:

BVA 13 Oil is an effective ULV diluent oil that is compatible with all pesticide active agents. BVA 13 is clear to white, odor free, and non-toxic.

Active Ingredient:

Refined petroleum distillate

Mode of Action:

BVA 13 acts as an inert diluent to allow for different mix and application ratios of other active pesticide products.

Where/When to use:

BVA 13 is used to dilute concentrated pesticide products, such as most mosquito control adulticide products to achieve the desired dilution rate customized for any aerial or ground application. It is commonly used for ground and aerial ULV applications of Permethrin, Resmethrin, Natural Pyrethrum, Etofenprox, and other concentrated mosquito adulticides.


  • 5 gl pail, 50 gl dr, 55 gl dr, 275 gl tote, Bulk


  • BVA 13 is a light grade petroleum oil that is clear to opaque in appearance which may be used as r a diluent for most mosquito control adulticides and on certain specified crops.
  • BVA 13 is a widely known product that is consistent in viscosity, free from excessive contaminants and debris which may cause damage to ULV systems.
  • BVA 13 is a low odor product that has a very discrete profile.


Pupae Control

Pupae do not ingest foodstuffs, therefore Bti and Bsph larvicides are ineffective.


Pesticides:  Use of chemical control measures are usually the least preferred option and generally utilized only as the last choice for control of mosquito populations.  These products are applied as directed by their respective labels, and all equipment used in this process is closely monitored and calibrated by staff.   Climatic conditions are always checked prior to any pesticide applications.  Wind speed and direction, and the possibility of impending rain are taken into consideration whether applying liquid or solid products because of drift, dilution, or chemical breakdown, depending on the product being used.  Temperature also plays a role, especially in the timing of applications and the choice of product used, as cooler temperatures warrant the use of water-based products while oil-based products may be used during warmer temperatures.  No applications are made when temperatures fall below 50 degrees F.


C-6:  Pesticides

The district will use pesticides when the aforementioned methods prove to be ineffective in controlling mosquito populations.  The District believes in using an integrated pest management (IPM) plan, using aforementioned methods as well as larval control, and pupae control, when possible, followed up with adulticide treatments if necessary, in accordance with strict guidelines of application to ensure the lowest environmental impact and avoidance of effecting non-target species.

NOTE:  Response Levels to Vector-Borne disease outbreaks may necessitate deviation from the NFMAD’s  PDMP.  The District’s treatment criteria and thresholds will be upheld without deviation except in times of acknowledged epidemic, as defined by the CDC, the Colorado Board of Public Health, and the Delta County Board of Health.  Clusters of human illness from mosquito-vectors in the district and county may require rapid response, before acknowledgment of epidemic is made by the CDC, or State of Colorado. Evidence-based mosquito-control, with rapid response to adult hatches and the presence of mosquito-borne illness is NFMAD’s top priority.  Notification of targeted spraying and/or fogging is not required by law, however every effort is made to inform the public when spraying/fogging is necessary.

NFMAD uses only appropriately calibrated equipment, ULV sprayers, and strictly adheres to all labeling.


Mode of Action:

Permethrin is a common synthetic chemical, widely used as an insecticide, an acaricide, and as an insect repellent. It belongs to the family of synthetic formulations called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to harm most mammals or birds. It generally has a low mammalian toxicity and is poorly absorbed by skin. AQUA-RESLIN is a synergized Permethrin (synthetic pyrethroid) formulation. The synergist piperonyl butoxide (PBO) aids by allowing the formulation to act faster and use less permethrin in doing so. AQUA-RESLIN is designed for application as an Ultra-Low Volume (ULV) aerosol to control adult mosquitoes and flies in residential, industrial, urban, recreational and other areas where adult mosquitoes and flies are found. The formulation greatly reduces the evaporation rate of water from the droplets and allows the water-based spray cloud to behave as that produced by a typical oil-based formulation.

Where/When to use:

AQUA-RESLIN is used for control of annoyance flies and mosquitoes, mosquitoes and flies of public health or disease vector importance in areas such as residential, industrial, and urban areas.


  • 2×2.5 gl cs, 30 gl dr


  • Unique patented formulation allows dilution with water rather than oil and yields a true water based formulation.
  • Fast and effective control of adult mosquitoes.
  • Provides quick knockdown and effective control of mosquitoes, black flies, gnats, biting and non-biting midges as well as other biting flies.
  • For aerial, ground, and barrier application.
  • May be applied undiluted or diluted in water.
  • ULV application provides excellent control at rates up to 0.007 pounds permethrin per acre.


Bayer Environmental Science


Short Description:

EVERGREEN® is a synergized pyrethrin formulation for ULV adulticide applications. The emulsifiable concentrate contains 0.5 lb pyrethrin and 5 lb of synergist (PBO) per gallon, which provides the highest pyrethrin to PBO ratio of 1:10. Labeled for aerial and ground ULV treatment, the concentration and specific gravity make this formulation an ideal choice where organophosphate or pyrethroid resistance is a concern. EVERGREEN is an option for use in product rotation for resistance management.

Active Ingredient:

Pyrethrin; 60% Piperonyl butoxide (PBO)

Mode of Action:

Acetylcholine Receptor Agonist, Neurotoxin. Pyrethrin affects the sodium channel at the nerve axon, which interferes with the nerve function causing repeated and extended misfiring of nerve impulses, causing quick paralysis and knockdown. PBO has no insecticidal activity, but has synergistic properties when combined with pyrethrin. The synergist interferes with insects’ ability to metabolize pyrethrin, thus allowing less pyrethrin to be required to produce mortality.

Where/When to use:

Approved for urban, rural, residential, agricultural areas, cropland, wetland, recreational areas, etc. Very broad range of use sites. No crop restrictions, however, not certified for organic crops.


  • 5 gl pail, 30 gl dr, 55 gl dr, 275 gl returnable tote


  • Provides highest synergist ratio for pyrethrin and PBO formulations.
  • Has higher specific gravity than most pyrethroid formulations, making it a good alternative for aerial applications.
  • Excellent choice for chemical rotation for resistance management.



PerManone: Now known as Pursuit, 2019

Short Description:

PERMANONE® is an oil based ULV product for safe and effective control of mosquitoes. PERMANONE exceeds all minimum requirements for scientifically based mosquito control programs. PERMANONE is a permethrin based product that is the most widely used chemical family in domestic mosquito control. The PERMANONE product group is considered to be a more environmentally friendly alternative without the unpleasant odors, corrosiveness, and paint damage associated with organophosphate products.

Active Ingredient:


Mode of Action:

The active ingredient, permethrin, belongs to a class of chemicals called pyrethroids. Pyrethroids work quickly by paralyzing the nervous system of insects. Pyrethroids kill insects by direct contact or when eaten.

Where/When to use:

PERMANONE products are recommended for applications as an ultra low volume (ULV) non-thermal aerosol (cold fog) to control adult stages of insects in residential, recreational and other areas where these insects are a problem.


  • PERMANONE Ready-To-Use is available in 2×2.5 gl cs, 30 gl dr, 275 gl tote and bulk shipments over 2,000 gl
  • PERMANONE 31-66 is available in 4×1 gl cs, 30 gl dr and 275 gl tote
  • PERMANONE 30-30 is available in 5 gl pail, 30 gl drums, and 275 gl tote


  • Quick knockdown, effective control of mosquitoes and target species.
  • Low odor, non-corrosive formulation.
  • Product degrades rapidly resulting in no residual effects.
  • Effective in controlling a wide range of mosquito species.
  • PERMANONE products have a long history of success in mosquito control.
  • No water setback.


Bayer Environmental Science


Short Description:

ZENIVEXTM contains the active ingredient etofenprox which is a new and unique molecule for adult mosquito control in the US. It contains no synergist (PBO) and it has a very favorable toxicity profile; it poses a low risk to human health and the environment. It is a non-organophosphate, non-carbamate, and non-ester pyrethroid. It has been shown to be highly effective in a wide range of habitats on a wide range of mosquito species. This new molecule provides very rapid and permanent knockdown of adult mosquito populations.

Active Ingredient:


Mode of Action:

Sodium channel blocker

Where/When to use:

As with any adulticide – apply when adult mosquitoes are most active around dusk and dawn and weather conditions are conductive to effective applications.

Depending on the habitat and mosquito pressure rates should be varied accordingly. As the amount of vegetation and/or mosquito pressure increases more optimum results are likely to occur with higher application rates.

ZENIVEX has been shown to be effective at all rates from 0.00175 to 0.007. Over 30 tests have been conducted in locations throughout the US on a wide variety of mosquito species with 90% or better mortality.

ZENIVEX can be the may stay product in any program, can be used as a rotational product to help preserve all chemistries we have, or can be the product of choice when mosquito pressure is high and maximum control is required to control high levels of nuisance or disease carrying mosquitoes.


  • 2×2.5 gl cs, 30 gl returnable dr, 120 gl returnable tote and 275 gl returnable tote


  • No piperonyl butoxide (PBO) – No concern about PBO buildup in the environment.
  • Non-ester pyrethroid (new adulticide chemical class) – May provide control of mosquitoes that are resistant to other adulticides.
  • Use diluted with ULV oil or undiluted – wide range of applications for effective control in wide range of environmental conditions.
  • Quick and Permanent knockdown – mosquitoes are knocked down in minutes and do not recover as with some other adulticides.
  • EPA reduced risk classification with an LD50 > 42,880 mg/kg: Poses low risk to humans’ health and environment and for improved safety of operators and bystanders.
  • Average half-life of 1.7 days in water and 4.4 days in soil. It rapidly breaks down in sunlight and does not persist in soil, surface water or sediment.
  • Etofenprox is a sodium channel blocker that provided rapid and permanent knockdown. This product works by contact and there is essentially no mosquito recovery once they are knocked down just minutes after application.


Central Life Sciences



The Field Manager and/or President of the Board must document the following procedures;

-Procedures for expeditiously stopping, containing, and cleaning up leaks, spills, and other releases to surface waters of the State of Colorado.  Employees who may cause, detect, or respond to a spill or leak must be trained in these procedures and have necessary spill response equipment available.  If possible, one of these individuals should be a member of the PDMP team.  For NFMAD, there are 3 members of the PDMP that may serve in this capacity.

-Procedures of notification of appropriate facility personnel, emergency response agencies, and regulatory agencies.

-Adverse Incident Response Procedures:  At a minimum, the Field Manager or Board President must have:

-Procedures for responding to any adverse incident resulting from pesticide applications.

-Procedures for notification of the adverse incident, both internal to the Decision-Maker’s agency/organization and external.  Contact information for the Division, nearest emergency medical facility, and nearest hazardous chemical responder must be in locations that are readily accessible and available.


NFMAD Pesticide Spill Procedures 2021

+In Accordance with the Colorado Commercial Pesticide Application and Safety Training guide, produced by the Co. Dept. of Agriculture, Division of Plant Industry and Colorado State University.

Pesticide spills can pose serious threats to human health and significant environmental contamination.  A thorough knowledge of the appropriate steps to take in event of a spill will help minimize the potential for adverse effects and save a great deal of money in expensive clean-up costs.  All NFMAD crew members must be prepared to handle spills BEFORE an accident occurs. Always have a spill kit available in pesticide storage and mixing areas. Remember:  Contamination can greatly increase when delaying a response to a pesticide spill due to lack of appropriate supplies.

Regardless of the magnitude, the objectives of a proper response are the same:  The three C’s of Spill Management

  1. CONTROL the spill
  2. CONTAIN the spill
  3. CLEAN it up

Control:  when attempting to control the flow of the chemical, do not expose yourself or other crew members unnecessarily. Always use and carry protective clothing and equipment when mixing, loading, and transporting pesticides.  Use the full uniform and protective covering when pesticide emergencies occur.

Contain:  After the leak has been controlled as well as possible, contain the spilled material in as small an area as possible.  With liquid spills, construct a dam to prevent the chemical from spreading.  It is particularly important not to allow any chemical to get into any body of water, including storm sewers

            Do Not Hose Down The Area; this will cause further spread of the chemical. Liquid spills can be further contained by spreading absorbent materials such as fine sand, vermiculite, sawdust, or clay over the entire spill.  For absorbing small spills and minor leaks, kitty litter is particularly useful.  Note:  Avoid the use of sawdust or sweeping compounds if the pesticide is a strong oxidizer.  Such a combination presents a possible fire hazard.

Clean up:  After the spill has been contained, if possible, pump or vacuum with a ShopVac as much of the liquid as possible into a tank designed specifically for this purpose or another empty spray tank, or one with the same material or a compatible pesticide, so that it may be applied to a labeled site.

After these preliminary stages of cleanup have taken place, it may be necessary to further decontaminate and neutralize the area.  This is particularly recommended if highly hazardous pesticides are involved.

Often a mixture of full-strength bleach and hydrated lime is effective for decontamination.  Work the solution into the spill area with a coarse broom.  Add absorbent material to soak up the cleaning solution.

Sweep and dispose the contaminated material.  Repeat the procedure until the area is thoroughly decontaminated.


When large amounts of pesticides are spilled on soils, effective decontamination is often not possible.  In these instances, the top 2-3 inches of soil should be removed and disposed of.  Cover the remaining soil with at least 2 inches of lime, then cover with fresh topsoil.

Minor spills on soil:  activated charcoal may be used in the cleanup.  The charcoal may absorb and tie-up enough chemical to avoid significant long-term injury.




Major spills on public property and all spills involving pesticides that are considered to be highly hazardous must be immediately reported to local and state emergency planning personnel.

Police and fire officials are our local contacts to whom such spills should be reported.  Call 911, and proceed to contain the site. These agencies will advise on the proper procedures for cleaning and disposing of accidentally released pesticides.  Failure to report such spills is considered to be a violation of the Emergency Planning and Community Right-to-Know Act (EPCRA/SARAIII).  Such violation can result in fines up to $25,000 for each day the violation continues.





ADDRESS OF OPERATOR__________________________________

ANY OTHER OPERATOR INVOLVED?:__________________________________________________________________________________________________

SITE WHERE SPILL OCCURRED______________________________

DESCRIPTION OF LOCATION_______________________________


HOW AND WHEN OPERATOR BECAME AWARE:_____________________________________________________________________________________________________

PHONE POLICE?__________FIRE DEPT.?_____________________

REPORTED TO:__________________WHEN____________________________

WITHIN 24 HOURS?______________________________________

IF NOT, WHY NOT?_______________________________________________________________________________________________________

NAME OF PESTICIDE(S):___________________________________________

______________________________________________________REGISTRATION_#________________________________________CONTROL PROCEDURES_____________________________________________________________________________________________________________________________________________________________________________________________________________

CONTAINMENT PROCEDURES_____________________________________________________________________________________________________________________________________________________________________________________________________________

CLEANUP PROCEDURES_____________________________________________________________________________________________________________________________________________________________________________________________________________


SURFACE WATERS INVOLVED:____________________________________





The Operator involved in an accidental pesticide spill or other adverse incident, or made aware of such an adverse incident which may have resulted from a discharge from a pesticide application, must immediately contact the Field Manager, and a Board Member, within 24 hours of the incident.

The Operator must include the following information:

The caller’s name and telephone number

Operator’s name and mailing address

Name and telephone of a contact person, if different from the reporter of the incident.

How and when the Operator became aware of the incident

Description of the adverse incident location

Description of the pesticide product, including the EPA registration number, for each product involved.

Description of any steps the Operator has taken or will take to correct, repair, remedy, cleanup, or otherwise address adverse effects. And, if known:

Any other Operator(s) involved in the incident.

If the incident is not reported in 24 hrs., why?All Notification of adverse incident and reporting requirements are in addition to what the registrant is required to submit under FIFRA section 6(a)(2) and its implementing regulations at 40 CFR Part 159.



Reporting of adverse incidents is not required under this permit in the following situations:

Operator is aware of facts that indicate that the adverse incident was not related to toxic effects or exposure from the pesticide application;

Operator has been notified by the board of directors and retains such notification, that the reporting requirement has been waived for this incident or category of incidents;

Operator receives obviously erroneous information regarding an incident or

An adverse incident occurs to pests that are similar in kind to the potential target pests identified on the FIFRA label.



Operators must provide a written report within 30 days of a reportable adverse incident within the district. The adverse incident report must contain the following information:

The date, time, and contact with board, at time of notification of incident.

Location of incident and any waters affected, with appearance (sheen, color, clarity, etc)

A description of the circumstances of the adverse incident, including species affected, estimated number of individual and approximate size of dead or distressed organisms, as well as magnitude and scope of affected area.  Include aquatic square area or total stream distance affected, and a description of the habitat.

The pesticide application rate, intended use site (on the bank, above waters, or directly to water), method of application, and the name of pesticide product and division registration number, along with any ambient water data.

If lab tests were performed, an indication of which tests were performed, the results, and a summary must be provided in 5 days, if not available then, add to the 30-day report.

Finally, a description of actions taken to prevent recurrence of adverse incidents, and a signature of the Field Manager or President of the Board, date, and certification.

One operator constitutes compliance for multiple operators involved in the incident, as long as each name is provided within the written report.


Operators must document the situation triggering the adverse incident and the corrective action planned within 30 days of becoming aware of the situation.  Retain a copy of this documentation.  This documentation must include the following:

-Identification of the condition triggering the need for corrective action review, including any ambient water quality monitoring that assisted in determining that discharges did not meet water quality standards.

-A brief description of the situation, and the date the problem was identified.

-Brief description of how the problem was identified, how the Operator learned of the situation, the date of awareness, and a summary of corrective actions both planned and taken.  Include the date initialed and the date of completion or expectation of completion.

-Any measures to prevent reoccurrence of such an incident, including notice of whether PDMP modifications are required or necessary as a result of the incident.





________________________________________ Rain Klepper, Board President

________________________________Elizabeth Durrance, Vice President

________________________________, Calvin Campbell, Secretary

________________________________Glenn Austin, Treasurer

________________________________Zach Hotchkiss, Board Member

________________________________, Field Mng.







The NFMAD board will modify the PDMP whenever necessary to address any of the triggering conditions for corrective action or when a change in pest control activities significantly changes the type or quantity of pollutants discharged.  Changes to the PDMP must be made before the next pesticide application that results in a discharge, if practicable, or if not, no later than 90 days after any change in pesticide application activities.  The revised PDMP must be signed and dated.

Pesticide Discharge Management Plan Availability

The Field Manager or Board President will retain a copy of the current PDMP, along with all supporting maps and documents, at the address provided in the Compliance Certification.  The PDMP and all supporting documents will be readily available, upon request, and copies of any of these documents provided, upon request, to the Division of State Permitting, EPA, or any other State, Tribal, or local agency governing discharges or pesticide applications within their respective jurisdictions. The Board of Directors of NFMAD may provide copies of the PDMP or other information related to this permit that is in its possession to members of the public.  Any Confidential Business Information (CBI), as defined by the State of Colorado, may be withheld from the public provided that a claim of confidentiality is properly asserted and documented in accordance with the constitution of the State of Colorado and the United States of America, however, CBI must be submitted to the State Division of Over-Sight of this permit, if requested, and may not be withheld from staff within the State Division.




All Operators must comply with the provisions of the PDMP


Operators of the NFMAD must receive training and review of the following situations:

-an unauthorized release or discharge associated with the application of pesticides, for example, a spill, leak or discharge not authorized by this or another CDPS permit, occurs.

-Operators of the district become aware, or the CO Division concludes, that Pest Management Measures are not adequate/sufficient for the discharge to meet applicable water quality standards.

-Any monitoring activities indicate failure to meet applicable technology-based effluent limitations in Part 2.

-An inspection or evaluation of activities by a CO Division official, or EPA local, state, tribal entity, reveals that modifications to the Pest Management Measures are necessary to meet the effluent limitations in this permit.

-Any Operator of the district observes or is otherwise made aware of an adverse incident.


If an Operator of the district determines that changes to the Pest Management Measures are necessary to eliminate any situation identified above, such changes must be made before or, if not practicable, as soon as possible after the next pesticide application that results in a discharge.


The occurrence of a situation may constitute a violation of this permit.  Correcting any situation does not absolve Operators of liability for any original violation.  However, failure to comply constitutes an additional permit violation.  The CO Division will consider the appropriateness and promptness of corrective action in determining enforcement responses to permit violations.  The CO Division may impose additional requirements and schedules of compliance, including requirements to submit additional information concerning the condition(s) triggering corrective action or schedules and requirements more stringent than specified in this permit.



Operators of the NFMAD will keep records as required by the district for the following activities:




Source Reduction


The following data is required for the above activities:

  1. Description of each treatment area, including location and size, acres or linear feet, of treatment area and identification of any surface waters of the State of Colorado, either by name or by location, to which pesticide(s) are discharged.
  2. Pesticide use pattern(s), against mosquito and other flying insects
  3. Target Pest(s) and explanation of need for pest control;
  4. Action Thresholds;
  5. Method and/or Data used to determine that action threshold(s) has been met;
  6. Description of pest management measure(s) implemented prior to the first pesticide application;
  7. Company Name and Contact Information for pesticide applicator;
  8. Name of each pesticide product used including the EPA registration number;
  9. Quantity of each pesticide product applied to each treatment area;
  10.  Pesticide application date(s); and
  11.  Whether or not visual monitoring was conducted during pesticide application and/or post-application and if not, why not, and whether monitoring identified any possible or observable adverse incidents caused by application of pesticides.



The District will retain the following records at the address provided on the Compliance Certificate:

  1. Copy of the Compliance Certification submitted to the CO Division, and any correspondence exchanged between the Decision-Maker(s) and the CO division specific to coverage under this permit;
  2. A copy of the PDMP, including any modifications made to the PDMP during the term of this permit;
  3. Documentation of equipment calibration;
  4. Information on each treatment area to which pesticides are discharged, including:




All required records will be documented as soon as possible, but no later than 14 days following completion of each pesticide application.  Operators will retain any records required under this permit for at least 3 years after the Operator’s coverage under this permit expires or is terminated.  Operators will make available to the CO Division, including an authorized representative of the Division, all records kept under this permit upon request and provide copies of such records, upon request.



To meet the effluent limitations of this permit, all Applicators must comply with this PDMP to minimize the discharge of pesticides to surface waters of the State of Colorado from the application of pesticides, through the use of Pest Management Measures.


To the extent not determined by the District, use only the amount of pesticide and frequency of pesticide application necessary to control the target pest, using equipment and application procedures appropriate for this task.


Maintain pesticide application equipment in proper operating condition, including requirement to calibrate, clean, and repair such equipment and prevent leaks, spills, or other unintended discharges.

Applicable Federal Requirements

Assess weather conditions (eg. Temperature, precipitation and wind speed) in the treatment area to ensure application is consistent with all applicable federal requirements.

Monitoring/Visual Monitoring Requirements for Pesticide Applicators

During any pesticide application with discharges authorized under this permit, all applicators must, when considerations for safety and feasibility allow, visually assess the area to and around where pesticides are applied for possible and observable adverse incidents, caused by application of pesticides, including the unanticipated death or distress of non-target organisms and disruption of wildlife habitat, recreational or municipal water use.

Visual Monitoring Requirements for all Operators

During any Operator post-application surveillance of any pesticide application with discharges authorized under this permit, all Operators must visually assess the area to and around where pesticides were applied for possible and observable adverse incidents, caused by application of pesticides, including the unanticipated death or distress of non-target organisms and disruption of wildlife habitat, recreational or municipal water use.

Inspection and Treatment Criteria

Applicators/Operators are required to record field and treatment data as outlined in this document (see recordkeeping)