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 MOSQUITO CONTROL SPRAY POLICY

 The Delaware Mosquito Control Section (Division of Fish and Wildlife, Department of 

Natural Resources and Environmental Control) utilizes an Integrated Pest Management (IPM) 

program to control mosquitoes in Delaware. 

I. CONTROL METHOD PRACTICES AND PRIORITIES 

 The Department's (DNREC's) first preference for control is to use environmentally-sound 

source reduction techniques such as Open Marsh Water Management (OMWM) for saltmarsh 

mosquito control, managing or manipulating water levels in high-level coastal impoundments so 

as to disrupt the mosquito’s life cycle, or stocking of larvivorous fishes in stormwater basins, 

backyard ornamental ponds, beaver ponds, etc. Such biological controls are effective in 

controlling an estimated 95 percent of mosquitoes breeding in areas treated with source 

reduction. The Department has a long-term program for implementing such approaches and is 

carrying out this program as time and resources permit. However, source reduction techniques 

are not suitable for some mosquito producing habitats, and in some cases landowners will not 

permit the Department to undertake the activities needed for source reduction purposes. In such 

circumstances, other control measures must then be employed. 

 The second preference for control is selective application of environmentally-compatible, 

EPA-registered larvicides (products designed to kill mosquitoes while they are still in the 

concentrated aquatic life stage) applied to the areas where mosquitoes breed. Aerial larviciding 

by fixed-wing aircraft or helicopters is usually not practiced directly over residential or 

developed areas, but ground-applied larvicides are frequently used to treat roadside ditches, 

flooded fields, used tire piles, abandoned swimming pools, woodland pools, median strip swales, 

lawn puddles, etc. in urban areas or suburban communities. Aerial larviciding by fixed-winged 

aircraft or helicopter is primarily used to treat freshwater wetlands, flooded woodlands, or 

coastal salt marshes or tidal wetlands, and is done only as warranted based upon intensive field 

surveys of larval occurrence, distribution and abundance. To be effective, larvicides must be 

applied during a very restricted period in the mosquito's aquatic phase of development. 

However, unfavorable weather or tidal conditions may prevent effective larvicide applications 

during this period. Larvicides routinely used in the recent past have included organophosphates 

such as temephos (Abate); but there is now a tendency to move toward third-generation 

larvicides, including juvenile growth hormone mimics such as methoprene (Altosid) or bacterial 

insecticides such as Bti (VectoBac, Aquabac, Teknar). These products may be either liquid or 

granular formulations. All larvicide products are applied according to federal, EPA-approved 

label specifications, as required by the Federal Insecticide, Fungicide, and Rodenticide Act 

(FIFRA). 

 When unfavorable larviciding conditions occur or larviciding has been unsuccessful, it 

might be necessary to resort to adulticiding (the term used to describe spraying practices to 

control adult mosquitoes). This type of spraying always occurs via a liquid formulation which 

ultimately becomes a fog or vapor. This is not to be confused with larviciding, which is often 

done via a dry/granular formulation. The adulticides used for the control of pestiferous mosquito 

species (e.g. organophosphates such as naled, or synthetic pyrethroids such as permethrin, 

resmethrin or sumithrin) are EPA-registered insecticides, which (like the larvicides) have 

demonstrated minimal human health or environmental risks, and as such can be sprayed over or 

within populated areas. The EPA has determined that all the mosquito control insecticides 

applied by the Mosquito Control Section can be used to kill mosquitoes without posing 

unreasonable risks to human health, wildlife or the environment (but this is not to say that there 

are no risks at all). Once again, all adulticide products are applied according to federally, EPA-
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approved label specifications, as required by the Federal Insecticide, Fungicide, and Rodenticide 

Act (FIFRA). The Department will keep abreast of any EPA announcements that would suggest 

that a pesticide of choice (larvicide or adulticide) might present greater risks to human health or 

the environment than previously thought, and certainly comply with any new EPA requirements 

affecting the use of individual pesticide products. 

 When adulticides have to be used, our first choice is to apply them aerially within or 

immediately adjacent to mosquito-breeding areas, immediately after the adult mosquitoes have 

emerged. This tactic is more effective and less expensive than spraying adulticides over 

widespread areas after the adults have dispersed. However, before newly-emerged adults 

migrate to upland zones, the time period available to achieve satisfactory control on or near their 

breeding habitats is even shorter than for larviciding. 

 In some cases, however, all of the above controls are inadequate to control mosquito 

populations prior to their movements into developed areas. In such cases, adulticiding in 

populated areas might have to be done, particularly if nuisance problems become intolerable or 

there is the chance of spreading mosquito-borne diseases. These adulticides might be applied 

aerially (primarily by fixed-wing aircraft) or by ground using truck-mounted sprayers. 

 This spray policy primarily addresses the issues of insecticide applications in populated 

areas, with an emphasis on adulticide use whether by aerial or ground applications. The best 

available scientific information from the EPA and product manufacturers, plus independent 

research by the University of Delaware and other sources, leads us to conclude that the products 

we use, and the manner in which we use them, pose no unreasonable risks to the public (human 

health), wildlife or the environment. The EPA’s product-labeling process reflects the permitted 

use and safety precautions that pesticide applicators must adhere to. The EPA, in order to 

designate a product’s approved use, has to complete a risk assessment, and has to determine that 

the final end use possesses extremely low human health or environmental risks when applied in 

accordance with federally-approved label instructions, as required by the Federal Insecticide, 

Fungicide, and Rodenticide Act (FIFRA). 

II. ADULTICIDING IN POPULATED AREAS 

 The decision to spray for mosquitoes in populated areas depends upon two forms of 

evidence indicating that mosquito populations are unacceptably high. The first form is physical 

evidence obtained in populated areas from professional analyses of adult mosquito light-trap data 

(where available) for population abundance and species composition, or upon adult mosquito 

landing rate counts. Light-trap counts in populated areas exceeding 25 adult females per night of 

pestiferous species, or landing rate counts averaging three (3) or more adults per minute in 

populated areas, indicate a nuisance condition substantially lowering the quality-of-life, as well 

as an enhanced possibility for mosquito-borne disease transmission. Except when there are 

additional reasons to believe that some mosquito species may be presenting a significant public 

health risk, no spraying will be conducted unless physical or complaint evidence suggests that 

spraying is warranted. 

 The second form of evidence is public complaints in populated areas, resulting in requests 

for spraying coming from either individuals, civic or homeowners associations, or local city or 

town officials within incorporated municipalities. To the extent practicable the Section will 

investigate in the field the need for a spray response based on the physical evidence previously 

described, collected in manner as can be practicably obtained in the field in consideration of 

mosquito species-specific diurnal/nocturnal activity patterns, sampling limitations, and staff or 

equipment logistical constraints. The Mosquito Control Section will decide whether spraying is 
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warranted on the basis of physical evidence alone; or by the merit, as determined by the Section, 

of a municipal request; or by the number and merit, as determined by the Section, of citizen 

complaints directly received by the Section. [In regard to public requests for adulticide 

spraying coming from incorporated areas, the Section requires that citizen requests for 

spraying during an infestation be coordinated and conveyed to the Section by phone 

through a designated municipal official.] 

 

III. PROTOCOLS FOR ADULTICIDING INCORPORATED MUNICIPALITIES 

 1. Mosquito Control Municipality Spray Endorsement 

 On an annual basis, each incorporated municipality (city or town) desiring aerial 

adulticiding or aerial larviciding will prepare and sign a waiver on official municipal letterhead 

permitting spray application of insecticides by low-flying aircraft for treatments to be done by 

the Delaware Mosquito Control Section or its contractors, in order to comply with Federal 

Aviation Administration (FAA) regulations. 

 Before the start of the pest season (by early or mid-March), the municipality will also 

acknowledge and agree to through a signed endorsement the Mosquito Control Spray Policy’s 

provisions, in order to allow and request the Mosquito Control Section to spray as warranted 

either all or portions of areas within the municipality's jurisdiction in accordance with this Spray 

Policy. Return of the signed endorsement requesting spraying will be needed for the Section to 

spray by fixed-wing aircraft, helicopter, or truck-mounted sprayer or fogger any adulticides or 

larvicides within a municipality’s borders, with exception of aerial spraying of larvicides over 

coastal tidal wetlands, and with exception of ground application of larvicides to tidal or non-tidal 

wetlands or other aquatic breeding sites by truck-mounted sprayers or hand application methods. 

[In regard to these last two situations, approval from municipalities is not necessary for the 

Section to aerially treat coastal tidal wetlands with larvicides, nor to make ground applications of 

larvicides in tidal or non-tidal wetlands or other aquatic breeding sites.] Without receipt of this 

signed endorsement, the Section will assume that the municipality does not want any aerial 

adulticiding or non-tidal wetland aerial larviciding, nor any truck-mounted spraying of 

adulticides, within their jurisdiction during the current pest season (mid-March through midNovember). If a municipality does not sign and return the endorsement before start of the pest 

season, it must be kept in mind that any change of thought resulting in a municipality to then 

request spraying later in the season cannot be honored until the endorsement is signed and 

returned to the Section, which in many cases might slow down or even prohibit the Section’s 

ability to provide timely treatment, even in response to severe nuisance problems or potential 

disease outbreaks. 

 2. Adulticide No-Spray Requests and No-Spray Zones 

 The Mosquito Control Section will not spray those municipality areas delineated by the 

municipality, and agreed to by the Section, to be zones where: 1) no aerial adulticide can be 

applied; or 2) areas where no ground adulticide can be applied; or 3) areas where neither method 

of adulticiding can be done. Residents/property owners within an incorporated municipality 

desiring not to be included in the aerial or ground adulticide program must make such requests 

known by contacting their local municipal government officials. The decision to request or 

authorize a No-spray zone within a municipality, and the consequences for doing such, are 

entirely the responsibility of a municipality’s officials. It is anticipated that such No-spray zones 

will not be sought by municipalities for non-residents or non-property owners (i.e. not applicable 

to casual visitors or tourists). The municipality, after accounting for factors given in Section 3 

below (for sizes of No-spray zones), will prepare maps of No-spray zones that were requested by 

their citizens and approved by the municipality, and submit these maps to the Mosquito Control 
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Section for review and concurrence. Please note that it is important that the locations and sizes 

of each No-spray zone within a municipality be identified each and every year, as there will be 

no automatic carryover of No-spray zone designations from previous years. The Section will 

review the submitted maps and inform the municipality in writing (by U.S. Mail or e-mail) of its 

concurrence. If concurrence cannot be given by the Section for the proposed No-Spray zones 

because of technical or logistical problems, the Section will then meet with municipal officials to 

resolve these problems. If a municipality wishes to modify the No-spray zone designations after 

the pest season has started (i.e. after mid-March), the municipality may request such 

modification from the Section, but should understand that the Section will need at least two 

weeks advance notice in order to comply with the requested modification. 

 With exception of a declared public health emergency by appropriate State-level agencies, 

it must be understood that within a municipality the decision to adulticide for mosquito control 

purposes or not to spray is totally up to municipal officials, who have to weigh several factors in 

making this decision, to then possibly be followed by requesting the Mosquito Control Section’s 

treatment services. These officials have to consider the impacts of intolerably high mosquito 

populations on quality-of-life factors and local economies, along with the possibility of 

mosquito-borne disease transmission, weighed against very negligible risks to human health or 

the environment when using EPA-registered adulticides in manner prescribed by the EPA, plus 

perhaps aircraft noise issues occasionally associated with aerial applications. If a resident or 

visitor to an incorporated city or town has a problem with this municipal decision, their 

complaint or grievance should be taken up with the municipality, not with the Mosquito Control 

Section. If a resident or visitor’s complaint or problem involves aircraft noise or other 

operational issues for how spraying was done, exclusive of concerns or issues dealing with 

pesticide exposure, the municipality should, in consultation with the Mosquito Control Section, 

attempt to directly address these issues with the resident or visitor making such complaint. If the 

complaint or problem concerns pesticide exposure, which in many cases is quite unavoidable in 

responding to a municipality’s request for adulticiding over or within populated areas, the 

Mosquito Control Section will assist a municipality in technically addressing a complaint or 

issue raised by a resident or visitor. However, it must be kept in mind that the Section applied 

the adulticide at the municipality’s request, in conjunction with the Section also independently 

investigating to the extent practicable that the adulticiding was warranted. 

 3. Sizes of No-Spray zones 

 Because of technical constraints, a No-spray zone for aerial adulticiding must be a 

minimum of 6 acres in size(approximately 500 ft. x 500 ft.), and a No-spray zone for ground 

spraying must be a minimum of 2 acres in size (approximately 300 ft. x 300 ft.). Operationally, 

in almost all cases it will probably not be necessary for the No-spray zone be much larger than 

these minimums (in order to avoid treating the residence where no spraying has been requested), 

but the final determination of the size of the No-spray zone will be made by the Section on a 

case-by-case basis. 

 It must also be recognized by the local municipalities that certain configurations or 

densities of No-spray zones might also prohibit adulticide spraying to an extent greater than the 

mere summation of individual No-spray zones. It must also be kept in mind that in many 

locations the creation of a No-spray zone for an individual residence will preclude adulticide 

treatment for many neighbors or nearby residences who desire pest relief -- this situation is a 

dilemma that the local municipality must resolve. 
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4. Requests for Adulticide Spraying within Municipalities 

 A city or town each year signing and returning an annual endorsement form does not mean 

that a municipality then automatically receives all of our mosquito control services whenever 

needed without any further actions on the city’s or town’s part. Converse to this and as a 

specific exception (and exclusive of a public health emergency that Mosquito Control might 

recognize), each and every time that a municipality wants Mosquito Control to undertake any 

adulticide spraying (to control adult mosquitoes), done by Mosquito Control either via groundbased or aerial applications within or over areas under a municipality’s jurisdiction, then the 

municipality’s designated Mosquito Control contact person (as indicated by the city or town 

on the endorsement form), or some other appropriate city or town official, must first contact the 

Mosquito Control Section and request such adulticiding. Please note that there can be 

occasions when Mosquito Control might recommend to a city or town that such type of spraying 

be undertaken (based on technical information that our program collects) and whereby we advise 

that the municipality then officially requests that we take such spray actions, but in many 

instances it will be more a matter of the city or town first contacting us on an event-by-event

basis to request that Mosquito Control performs some adulticide spraying (which could be 

determined by a city or town as being necessary or desirable for Mosquito Control to undertake 

via a municipality hearing from its citizens or constituents about intolerable local mosquito 

infestations, or by other means or devices that a city or town might have at its disposal). For 

cities or towns in New Castle County and northwestern Kent County (for the latter to include all 

municipalities north of Dover to the west of Rt. 13, plus Smyrna too), the number to call is our 

Glasgow office at 302-836-2555; for cities or towns in the remainder of Kent County and all of 

Sussex County, the number to call is our Milford office at 302-422-1512. 

 5. Advance Notification of Spray 

 When there is a good probability that adulticiding operations are imminent within a 

municipality, to the extent practicable for sake of public notification the Mosquito Control 

Section will, for each adulticiding event (whether done by air or truck), do the following: 

1) contact in advance by telephone an appropriate government official and provide by telefax a 

spraying announcement to each affected municipality; 

2) place a phone spraying announcement on a Mosquito Control Section recorder that citizens 

can call toll-free at 1-800-338-8181 to find out about the status of spraying; 

3) on a statewide basis, contact over 12 local radio stations by telefax and provide a spraying 

announcement, which the radio stations may or may not choose to broadcast; 

4) post a similar spraying announcement on the Mosquito Control Section’s (Division of Fish 

and Wildlife’s) DNREC webpage, which the public can access via the Internet at 

http://www.fw.delaware.gov/Services/MosquitoSection.htm (go to “Mosquito Spraying 

Announcements” once you have accessed this webpage). 

5) for anybody who wants to personally receive via e-mail up-to-date spraying announcements, 

they can subscribe to a Mosquito Control listserver that will automatically disseminate such 

announcements to them via the Internet (simultaneously done in conjunction with posting these 

spraying announcements on Mosquito Control’s DNREC webpage)-- the sign-up for this 
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listserver can be accomplished by accessing the Mosquito Control webpage address given above 

in item #4; 

6) finally, immediately prior to aerial applications of adulticides, the treatment aircraft will 

briefly circle over pertinent areas within a municipality, to provide final notification or signal in 

the field of intention to spray. 

 Any additional notification of intent to spray is up to the participating municipalities to 

perform or offer, but it is probable that giving additional public notice going beyond what the 

Mosquito Control Section presently performs would not be very feasible or practicable to do. 

 To the extent feasible and practicable, with exceptions for health emergencies or when 

contending with unsettled weather conditions for spraying, such advance notification will be 

issued by the Mosquito Control Section at least four (4) hours before any adulticide spraying 

begins, and be done for every adulticiding effort within a municipality’s jurisdiction. 

 The advance notification procedure for spraying described above will now also be 

followed for every aerial larviciding effort within a municipality's jurisdiction (in the past, such 

notice was routinely provided for spring woodland control aerial larviciding and other aerial 

treatments of freshwater wetlands, but was not done for aerial larviciding of coastal marshes). 

While aerial larviciding operations in treating wetland breeding sites usually do not involve 

spraying directly over people, the unfortunate terrorism events of September 11, 2001 have now 

greatly increased the public’s concern and anxiety about possible bioterrorism incidents, which 

could occur (at least in theory) via pesticide spray delivery systems, so it is now prudent to 

ensure that municipal officials are fully aware in advance of any-and-all adulticiding (whether 

done by air or truck) or aerial larviciding within their jurisdictions. What will not be publicly 

announced will be truck-based spraying of larvicides (e.g. along roadside ditches) or handapplied larviciding done on foot (e.g. when treating localized breeding sites in small pocket 

marshes or in residential areas), since these types of activities are: 1) sometimes numerous and 

scattered; 2) are often not determined to be necessary until actually on-site; and 3) because of 

their carefully targeted applications to localized surface water (as opposed to the widespread 

spraying of adulticide aerosols over uplands or marshes by aircraft or truck, or the relatively 

widespread aerial spraying of larvicides over wetlands), such applications hardly generate any 

public awareness, concern or comment. 

 For sake of good communications, and to help other agencies respond to possible public 

inquiries about mosquito control spraying activities, advance notifications of spraying are also 

provided by the Mosquito Control Section via telefax or e-mail to the Delaware Emergency 

Management Agency (DEMA), to each county’s 911 Emergency Call Center, and to the 

Delaware Department of Agriculture’s (DDA) Pesticide Compliance Section and to the DDA’s 

State Apiarist. 

 Additionally, by a working agreement adopted in 2001 among the Mosquito Control 

Section, the DDA’s State Apiarist, and the Delaware Beekeeping Association, for all aerial 

adulticide spray announcements the Mosquito Control Section now indicates via coded gridblock numbers (for a special map of Delaware) where aerial adulticide spraying activities are 

intended to occur. By the tri-party working agreement, it is incumbent upon commercial 

beekeepers to assume responsibility for their keeping up-to-date and for their being aware about 

locations where aerial adulticiding is soon intended, achieved by the beekeepers taking 

advantage of the various spray announcement devices mentioned above (i.e. toll-free phone 

calls, radio announcements, webpage postings, listserver e-mails). If a commercial beekeeper has 

a problem with where some spraying will soon occur, the beekeeper should then inform the 

Mosquito Control Section in timely manner about such concerns, so that appropriate spray 

measures can be taken by Mosquito Control to avoid or minimize any adverse impacts to 
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beekeeping operations. Since commercial beekeepers frequently move their bee colonies around 

in addressing crop pollination needs, and since the need for mosquito control spraying can be 

quite geographically variable and occur with relatively short notice, it is important that good 

two-way communications be maintained between Mosquito Control and commercial beekeepers, 

which adherence to the working agreement’s protocols is intended to provide. The State Apiarist 

distributes to each of Delaware’s registered beekeepers a copy of the working agreement and the 

coded grid map. 

 6. Time of Spraying 

 To the extent feasible and practicable, adulticide spraying will be conducted at times 

which minimize direct human exposure (preferably early morning or late evening for aerial 

applications). During the summer peak “tourist season” from the Friday evening immediately 

before the Memorial Day weekend through the Monday evening of Labor Day weekend, aerial 

adulticide applications in the “coastal resort strip” from Lewes to Fenwick Island may be made 

on weekdays in the morning from 5:30 to 8:30 a.m. and in the evenings from 6:00 to 9:00 p.m., 

excluding the weekend that is defined here as Friday evenings through Monday mornings (and 

through Monday evenings on holiday Mondays). The “coastal resort strip” itself may be viewed 

as extending landward of the Atlantic Ocean coastline from Lewes to Fenwick Island a distance 

of up to about 5 miles inland, as well as about 2 miles landward of the primary bayshores 

composing the Inland Bays. Exceptions to not aerially adulticiding the coastal resort strip 

between Friday evening and Monday morning can occur at special request (in writing) from a 

municipality, or in event that inclement weather or other circumstances prevent adulticiding at 

other times, whereby only the Friday evening to Monday morning weekend period is left for 

timely spray application. Aerial adulticide applications will only be made when weather 

conditions comply with product-label spraying requirements (e.g. clear visibility and winds no 

more than 10 mph). Outside the coastal resort strip area, the weekend exclusion for adulticide 

spraying will not apply, but the daily time slots for spraying will still apply. An exception to the 

desired early morning and evening times for aerial spraying can occur when unusual weather 

conditions (e.g. fog, excessive wind, temperature inversions) preclude applications at the desired 

times, and yet the mosquito situation is so bad that spraying must still be performed that day, in 

which case spraying would also be permissible in the day between early morning and late 

evening. Ground applications of adulticides statewide may generally be done from early evening 

through early morning on weekdays or weekends, except that municipalities within the coastal 

resort strip from Lewes to Fenwick Island during the summer peak “tourist season” will 

generally not receive ground adulticide applications on the weekends (defined as above); 

municipalities within the coastal resort strip still might be ground-sprayed on weekends at 

special request (in writing) of a municipality, or if inclement weather or other circumstances 

prevent timely ground applications at other times. Ground applications will only be done when 

weather conditions comply with product-label spraying requirements. 

 7. Adulticides Used 

 The Mosquito Control Section may aerially apply by twin-engine aircraft at application 

rates up to those indicated below one or more of the following adulticides, with the choice of 

which product to use per spray event dependent upon the problem species to treat and other 

technical factors or local considerations: 
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1) Dibrom Concentrate (naled) applied at 0.10 lbs. AI/A, applied in ULV concentrated 

formulation of 1.0 oz./A, or 

2) Trumpet EC (naled) applied at 0.10 lbs. AI/A, applied in ULV concentrated formulation of 

1.2 oz./A, or 

3) Scourge 18%+54% MF (resmethrin + PBO) applied at 0.007 lbs. resmethrin AI/A + 0.021 

lbs. PBO AI/A, mixed with mineral oil, applied at a total volume of 3 oz./A (O.6 oz. 

Scourge 18-54/A plus 2.4 oz. mineral oil/A), or 

4) Anvil 10+10 (sumithrin + PBO) applied at 0.0036 lbs. AI/A, applied in ULV concentrated 

formulation of 0.62 oz./A, or 

5) Permanone 31-66 (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral oil 

applied in ULV concentrated formulation, or 

6) Biomist 31+66 ULV (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral 

oil applied in ULV concentrated formulation, or 

7) Kontrol 31-67 Concentrate (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with 

mineral oil applied in ULV concentrated formulation, or 

8) Evoluer 30-30 ULV (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral oil 

applied in ULV concentrated formulation, or 

9) Aqualuer 20-20 (permethrin + PBO) applied at 0.0035 lbs. AI/A applied in ULV 

concentrated formulation. 

10) Zenivex E20 (etofenprox) applied at 0.00175-0.0070 lbs. AI/A applied ULV in undiluted, 

concentrated formulation; or mixed with mineral oil and also applied ULV. 

 The following adulticides may be ground applied at application rates up to those indicated 

by truck-mounted Beecomist ULV (Ultra Low Volume) or London Fog ULV ground foggers: 

1) Scourge 18%+54% MF (resmethrin + PBO) applied at a rate up to 0.007 lbs. resmethrin 

AI/A + 0.021 lbs. PBO AI/A, mixed with mineral oil, applied at a total volume of 3 oz./A 

(0.6 oz. Scourge 18-54/A plus 2.4 oz. mineral oil/A), or 

 

2) Anvil 10+10 (sumithrin + PBO) applied at 0.0036 lbs. AI/A, mixed with mineral oil, applied 

at a total volume of 1.24 oz./A (0.62 oz./A Anvil 10+10 plus 0.62 oz. mineral oil/A), or 

3) Permanone 31-66 (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral oil 

applied in ULV concentrated formulation, or 

4) Biomist 31+66 ULV (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral 

oil applied in ULV concentrated formulation, or 

5) Kontrol 31-67 Concentrate (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with 

mineral oil applied in ULV concentrated formulation, or 
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6) Evoluer 30-30 ULV (permethrin + PBO) applied at 0.0035 lbs. AI/A, mixed with mineral oil 

applied in ULV concentrated formulation, or 

7) Aqualuer 20-20 (permethrin + PBO) applied at 0.0035 lbs. AI/A, applied in ULV 

concentrated formulation. 

8) Zenivex E20 (etofenprox) applied at 0.00175-0.0070 lbs. AI/A applied ULV in undiluted, 

concentrated formulation; or mixed with mineral oil and also applied ULV. 

9) Duet (prallethrin + sumithrin + PBO) applied at 0.0003-0.0008 lbs. AI/A for prallethrin 

component, plus 0.0012-0.0036 lbs. AI/A for sumithrin component, both applied as a 

packaged mix in ULV concentrated formulation. 

 The Mosquito Control Section will make accessible via the Internet a copy of each 

adulticide’s product label and its accompanying Material Safety Data Sheet (MSDS) to each 

municipality for their information. 

 

8. Larvicides Used 

 The Mosquito Control Section may apply at application rates up to those indicated one or 

more of the following larvicides aerially by twin-engine aircraft or helicopter, or from the 

ground using truck-mounted sprayers or hand application methods, with the choice of which 

product to use per spray event dependent upon the problem species to treat and other technical 

factors or local considerations: 

1) Abate 4E (temephos) applied at 0.048 lbs. AI/A, applied at 1.5 oz. Abate 4E/A mixed with 

water to achieve a final application volume of 64 oz./A, or 

2) Abate 5BG (temephos) applied at 0.1 lbs. AI/A, applied in granular formulation at 2 lbs./A, 

or 

3) Abate 2BG (temephos) applied at 0.1 lbs. AI/A, applied in granular formulation at 5 lbs./A, 

or 

4) VectoBac 12AS (Bti) applied at 32 oz./A, or 

5) VectoBac CG or G (Bti) applied in granular formulation at 10 lbs./A, or 

6) Aquabac XT (Bti) applied at 32 oz./A, or 

7) Aquabac 200G (Bti) applied in granular formulation at 10 lbs./A, or 

8) Teknar HPD (Bti) applied at 32 oz./A, or 

9) Teknar G (Bti) applied in granular formulation at 10 lbs./A, or 

10) Altosid Liquid Larvicide (5% methoprene) applied at 0.013 lbs. AI/A, applied at 4 oz./A 

mixed with water to achieve a final application volume of 32 oz./A, or 

11) Altosid Liquid Concentrate (20% methoprene) applied at 0.013 lbs. AI/A, applied at 1 oz./A 

mixed with water to achieve a final application volume of 32 oz./A, or 
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12) Altosid Pellets (methoprene) applied at 10 lbs./A, or 

13) Altosid SBG (methoprene) applied in granular formulation at 10 lbs./A, or 

14) Altosid Briquets (methoprene) applied at one briquet/100 sq. ft., or 

15) Altosid XR Extended Residual Briquets (methoprene) applied at one briquet/200 sq. ft., or 

16) VectoLex CG (Bacillus sphaericus) applied in granular formulation at 20 lbs./A, or 

17) Agnique MMF (nonionic surfactant) applied at 3 oz/1000 sq. ft., or 

18) Arosurf (nonionic surfactant) applied at 3 oz/1000 sq. ft. 

 The Mosquito Control Section will make available via the Internet a copy of each 

larvicide’s product label and its accompanying Material Safety Data Sheet (MSDS) to each 

municipality for their information. 

 9. Public Health Emergencies 

 In the event of an Eastern Equine Encephalitis (EEE), St. Louis Encephalitis (SLE), or 

West Nile Encephalitis (WNE) public health emergency, jointly recognized by DNREC and the 

Delaware Division of Public Health, aerial or ground adulticiding might be carried out over 

municipalities that have not signed the Spray Policy endorsement agreeing to permit such 

activities, as well as spraying also possibly occurring in designated No-spray zones, ceasing 

when the public health emergency is terminated. In event of a public health emergency, general 

public health considerations to prevent or lessen serious disease problems must take precedent 

over individual desires to avoid a short-term exposure to an insecticide that is registered by the 

EPA for application over populated areas, with knowledge that such exposures will of course 

take place but which are of minimum risk to human health and safety. The Section will try to 

continue to observe to the extent feasible and practicable its policies on advance notification, 

timing of spraying, and type of insecticides used, but public health concerns during emergencies 

may necessitate deviations from these protocols, such as for application timing, for treating Nospray zones, etc. 

IV. PROTOCOLS FOR ADULTICIDING UNINCORPORATED AREAS 

 The spraying of adulticides by aerial or ground application in unincorporated areas does 

not require a signed Mosquito Control Spray Policy endorsement such as is needed prior to 

spraying incorporated municipalities. Because of insurmountable practical and logistical 

problems in communicating with individual citizens or civic associations in unincorporated 

areas, the Mosquito Control Section must assume that timely and safe adulticiding is allowable 

and desired whenever pest populations become excessive or mosquito-borne disease potentially 

threatens. The Section will determine when and where adulticiding is necessary, based on 

physical evidence and in conjunction with complaints from individual citizens or civic 

associations. Similarly, the Section’s ability to use larvicides, whether applied aerially or by 

ground, will not require any signed endorsements for when spraying is done in unincorporated 

areas. 

 Requests for no spraying of ground or aerially-applied adulticides in unincorporated areas 

can be made by individual residents or property owners by directly contacting the Mosquito 

Control Section, to request a form for applying for No-spray zone consideration, which after 
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completion should then be returned to the Mosquito Control Section at the address indicated on 

the form (note: to request the application form, contact the Mosquito Control Section at 302-739-

9917; or write to Delaware Mosquito Control Section, Division of Fish and Wildlife, DNREC, 

89 Kings Highway, Dover, DE. 19901; or you can download a copy of the form over the 

Internet, by accessing http://www.fw.delaware.gov/Services/MosquitoSection.htm, and then go 

to “Request a No-spray Zone application”). All such requests must be made prior to March 1 

for each pest season and must be made in writing using the approved form, which will request 

information such as name, address, and telephone number of the resident or property owner 

requesting no spraying, a map indicating the location of the property not to be adulticided, and 

the reason(s) for requesting the No-spray zone. The names, addresses and phone numbers of all 

residents or property owners bordering a property where no spraying is requested, or who would 

be located within the requested No-spray zone block, must also be submitted by a person 

requesting a No-spray zone. This will assist the Mosquito Control Section in evaluating the Nospray zone request and in providing explanations to people who might then not receive pest 

relief services, resulting from their neighbor being granted a No-spray zone designation. 

However, if the entire requested No-spray zone block all fits inside the property of the person 

requesting such designation, with the borders of the requested No-spray zone coming no closer 

than 300 feet to any neighbor’s property boundaries, then submitting information about 

neighboring residents or property owners will not be required. Individuals must indicate whether 

they are requesting no aerially-applied adulticides, no ground-applied adulticides, or both. This 

request for no spraying must be submitted each and every year using the approved form, as there 

will be no automatic carryover of No-spray zone requests from year to year. If an individual 

citizen or civic association in an unincorporated area wishes to request a No-spray zone after the 

pest season has started (i.e. after mid-March), such requests may be submitted in writing to the 

Section similar to requests made prior to mid-March. However, due to the logistical problems in 

changing operational spraying procedures and advising contractors of revisions, the requester 

should understand that the Section will need at least two weeks advance notice in order to 

consider and review the request and to initiate procedural changes (if any). 

 Based upon the written requests for no spraying of adulticides, the Section will determine 

the need for and boundaries of No-spray zones and will notify the individual of the Section’s 

decision. When possible, the Section prefers that individual requests for no spraying in areas or 

neighborhoods that have civic associations be coordinated and conveyed in writing to the 

Section by the civic associations prior to mid-March; however, individual requests can still be 

presented to the Section. 

 The application of adulticides in unincorporated areas will be similar to what is done in 

incorporated municipalities regarding times of spraying, insecticides used, and public health 

emergencies. However, in regards to providing advance notification of each spraying event, and 

because of insurmountable logistical problems, telephone calls or other personal contacts by the 

Section to individual citizens or civic associations will not be made. Nonetheless, concerned 

citizens can still inquire about the Section's intentions to spray by contacting, on a daily basis, 

the toll-free phone recording at 1-800-338-8181 or the Section’s webpage posting at 

http://www.fw.delaware.gov/Services/MosquitoSection.htm (and go to “Mosquito Spraying 

Announcements” on the webpage), or they can subscribe to the Section’s listserver to 

automatically receive such spray announcements via the Internet, and they can also be aware of 

pending spray operations by listening to any spray announcements that may be broadcast by 

local radio stations. 
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V. RESOLVING CONFLICTS IN UNINCORPORATED AREAS BETWEEN 

PERSONS REQUESTING NO SPRAYING VS. PERSONS WANTING PEST 

RELIEF VIA ADULTICIDING 

 Whenever possible, persons living in unincorporated areas who do not desire adulticiding 

will try to be accommodated by the Mosquito Control Section. However, conflicts sometimes 

arise when one or more nearby neighbors demand adulticiding for pest relief. Such conflict can 

arise either during the consideration or designation process for a No-spray zone or after a Nospray zone has been designated. When such conflict arises, the Section will attempt to resolve 

the disputes on a case-by-case basis, resulting in either continuation or resumption of 

adulticiding measures, modification of adulticiding measures, or stopping or continued cessation 

of adulticiding measures. Value judgments of public health, safety, comfort and quality-of-life 

must be weighed against the health or other concerns of an individual requesting no spraying. 

Individuals with special medical problems possibly attributed to pesticide exposure can obtain a 

physician's written opinion acknowledging pesticide sensitivity, and such people will be given 

special consideration by the Section to the extent feasible and practicable. The Section will try 

to resolve all conflicts in a manner acceptable to all parties, but public health concerns (e.g. 

arbovirus encephalitis outbreaks) must take precedence over other considerations. For most 

individuals having health-related concerns involving adulticide exposures, such people can 

satisfactorily minimize their concerns by paying attention to the advance spray notification 

process, followed by their taking common-sense measures to minimize or avoid exposure (e.g. 

temporarily leave the spraying area, temporarily moving inside, temporarily closing windows 

and doors, etc.). However, please note that given the safety of the types of EPA-registered 

adulticides or larvicides that the Section uses, and how these products are then applied with very 

minimal human health risks, which for a vast majority of people no special precautions need to 

be taken to avoid exposure to the Section’s operational spraying. 

VI. POLICY APPLICABILITY – TYPES OF SPRAY APPLICATIONS 

This policy’s requirements to request participation of incorporated cities or towns, and to 

give advance notice of intention to spray in incorporated cities or towns, is applicable to aerial 

applications of adulticides, as well as for ground application of adulticides when delivered by 

truck-mounted sprayers. Participatory consent by cities or towns is also needed for aerial 

applications of larvicides during the spring woodland control program or for aerial larviciding of 

other freshwater wetlands; but such participatory consent from municipalities is not needed for 

aerial larviciding over coastal tidal wetlands, nor for the ground application of larvicides by 

truck-mounted sprayers or hand application methods. However, advance spraying notice of all 

aerial larviciding within municipalities will be given. This policy’s requirements for the 

Mosquito Control Section to give advance notice to cities or towns of intention to spray is not 

applicable to ground applications of larvicides when delivered by truck-mounted sprayers or onfoot by back-pack sprayer, hand-held sprayer, or hand toss. [It must be noted that if a 

municipality desires only on-foot applications of insecticides that are done by hand, and does not 

agree to aerial applications of insecticides nor to adulticide applications by truck-mounted 

sprayers, in many cases and locations it will then not be possible to provide satisfactory nuisance 

control or disease prevention.] 

The spray policy is also applicable to insecticide applications that are made for mosquito 

control in unincorporated areas, in regard to many needs, matters or practices that are similar to 

what occurs in cities or towns; as well as providing some protocols that are specific or unique for 
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adulticiding in unincorporated areas, where municipal government interactions are not possible 

nor applicable. 

Finally, requirements to follow this spray policy can be waived by DNREC during a 

declared public health emergency (see Section III-8). 

VII. GENERAL EMERGENCY WAIVERS 

 The Department, for exceptional circumstances or during emergencies, may modify this 

policy on a case-by-case basis. 

VIII. POLICY ADOPTION 

 This "Mosquito Control Spray Policy" is adopted as Delaware Department of Natural 

Resources and Environmental Control management policy, and supersedes any previous written 

or unwritten policies. 

 First formulated and adopted in February, 1990. 

 Latest revision = January 26, 2009.