A Dozen
Frequently-Asked Questions (FAQs) – Mosquito Control Section
Introduction
The performance of mosquito control presents many challenges to its
modern-day practitioners, and not surprisingly is of much interest to many
people. Mosquito control in
As natural resource management professionals charged
with mosquito control responsibilities, we are being asked to perform some
complex undertakings. We are tasked to
somehow reach into the environment to eliminate or nullify a set of quality-of-life, public health, and
economic problems of much serious concern to many Delawareans. These problems are generated by organisms
that in their immature stages are found throughout the state in almost every
type of aquatic habitat imaginable (with exception of the middle of fast-running
streams), and which if uncontrolled are airborne as adults and capable of
widespread dispersal and much pestilence.
The most practicable modern control tools that we have at our disposal
are insecticides that we must judiciously spray over or within wetlands or
other breeding habitats to control immature stages, but which we also sometimes
have to directly apply over or within where people live or work to control
adult mosquitoes; plus various wetland management techniques for larval control
that must be carefully installed or implemented in very sensitive, very
valuable environments.
It is not unusual for many people to understandably demand even more mosquito control than what we can reasonably deliver given environmental constraints and our available resources; whereas other folks without a good understanding of what we do and how we have to do it, are sometimes quite critical of our control methods. Indeed, we do not have an easy mission to fulfill. To help the general public, elected or appointed officials, media, civic associations, environmental organizations, and other special interest groups better understand what we do and how we do it, we have compiled a set of a dozen (12) Frequently Asked Questions (“FAQ”) below, along with their answers, which we hope will shed some light on our program. The 12 FAQ’s are as follows:
1) Why are the mosquitoes so
bad around my house, and what can I do or whom can I
call?
2) Why do we need mosquito
control? What do you do this for?
3) What kinds of insecticides
are used, and when do you use them?
4) Why do you have to use
insecticides at all? Aren’t there better
ways to achieve control? What other approaches do you use?
5) Are mosquito control
insecticides safe to use, and should I be concerned if I’m exposed to spraying?
6) How can I find out when and where mosquito
control spraying might be done?
7)
If I
don’t want to be exposed to mosquito control spraying, what steps might I take?
8)
What personal protection measures can I take
to help avoid mosquito bites?
9)
What do
I do if I find a sick/dead wild bird that might have
10) What are human health problems/symptoms when a
mosquito-borne viral disease is contracted?
And what is the probability of my becoming infected or sick?
11) There
are a lot of biting flies around here that I don’t like (or gnats, or ticks, or
wasps, etc.). Can’t Mosquito Control do
something to get rid of them?
12) Describe
the Mosquito Control Section. How many
people work for you? Who are you
folks? Where do you work? What do you do in the winter? Who do you work with? Who are your partners? What’s your budget?
A Dozen (12) Mosquito Control FAQ’s
1) Why are the mosquitoes so bad around my house, and what can I do or whom can I call?
Many adult mosquitoes around the home often come from breeding sites within the neighborhood or in close proximity to residential areas. To help minimize mosquito annoyances, homeowners should take steps to eliminate or reduce standing or stagnant water on or nearby their properties, including attending to potential mosquito-breeding habitats such as clogged rain gutters and downspouts, poorly-drained flat roofs, old tires, abandoned inground or aboveground swimming pools (including plastic kiddie wading pools), unused bird baths, depressions in boat cover-tarps, bilge water in boat bottoms, flower pot clay liners, garbage cans or their upturned lids, discarded soda or paint cans, wheelbarrows, or any other types of structures or containers that can collect and hold water for 4 or more consecutive days. [Just imagine the numbers of nooks-and-crannies that might hold rainwater in an auto salvage yard or a scrap tire pile!] In addition, any grading of topsoil for grass planting or following septic system installation should ensure that rain or sprinkler-system water does not become trapped on the surface. Ornamental ponds can also breed mosquitoes, and since you obviously want water here, other control measures might have to taken – e.g. ensuring good flow or changeover of water to avoid stagnant conditions, stocking or raising fishes that eat mosquito larvae, or judicious treatment with an appropriate mosquito larvicide.
Mosquitoes can also breed in roadside ditches, wet woodland pools, or stormwater management basins where water is held for 4 or more consecutive days. In many situations, a homeowner has limited physical capability or legal ability to eliminate these nearby breeding sites, and as such should contact the Mosquito Control Section to report such problem areas, which might then lead to the Section helping to physically eliminate the breeding habitats, or to our making the reported problem sites part of the Section’s surveillance and insecticide treatment program. Frequently, mosquito annoyances around the home might not originate from the immediate vicinity at all, since some mosquito species have flight ranges of 5-15 miles away from their breeding sites in order to seek bloodmeals – saltmarsh mosquitoes and some woodland species are well known for their long flight distances. A substantial amount of Delaware’s saltmarsh mosquito production problems arise from Bombay Hook and Prime Hook National Wildlife Refuges, to then potentially affect people in off-Refuge locations, and it is only through good cooperation with the U.S. Fish and Wildlife Service that we are able to spare many Delawareans from Refuge-produced skeeters. In such situations where a private landowner cannot due much to control the mosquitoes that eventually make it to his/her property, only the Section’s intervention can help. When you have need to contact the Mosquito Control Section about an intolerable nuisance situation or a suspected breeding problem, in New Castle County please call 323-4492 (our Bear operational HQ); and in Kent or Sussex Counties please call 422-1512 (our Milford operational HQ).
Since our field inspectors and surveillance/monitoring devices cannot be everywhere around the State during the time a mosquito brood is in progress, we rely in part upon receiving public complaints to help us target where we might best spend our limited resources. Your calling one of the two the numbers above is an important, valuable way to help us to focus our response actions, and your complaint situation will usually be verified as soon as possible through one or more of our field surveillance methods discussed in FAQ #3 below. For your getting the most rapid response from our control program, and for our most accurately receiving and recording the information you want to provide (and that we need to have), we ask that you call us directly, rather than your first going through an elected official or third party (i.e. please do not immediately call your State Senator, State Representative or a County official) – if for some reason you become dissatisfied with our response or service, you could always then follow-up by contacting an elected official or third party, but even then we would first appreciate your direct callback, to see if we could still try to rectify your problem.
One exception to your first calling
the Mosquito Control Section is that if you live in an incorporated
municipality and desire to request spraying for relief from biting adult
mosquitoes, you must first contact your appropriate city or town official,
since by our Spray Policy we only provide such spraying services within a
municipality’s borders only upon official requests from city or town
officials. If you do not know who your
appropriate local officials might be, you can call the Mosquito Control Section
and we will provide you with their names and phone numbers. Additionally, for residential subdivisions
in unincorporated areas of
Please understand that during periods of peak mosquito outbreaks, our agency often receives dozens of call per day, and within just several days this can amount to a backlog of hundreds of complaints. When such problems pile-up, as they all too frequently do, we are then forced to prioritize even further where and when we’ll treat, trying to provide the most relief to the most people in the fastest time, so depending upon your situation from a statewide perspective, you or your neighbors might not always get as rapid a response as you might desire. But as always, no matter how you might end-up requesting our control services, or where you might end-up in our prioritizations for response, we will continue to try to do the best we can with the resources we have been provided.
2) Why do we need mosquito control? What do you do this for?
If you were the caller in FAQ #1 above contacting us about intolerable
mosquito nuisance problems around your home, then you already know a prime
reason for why we’re in business. At one
time before the advent of modern mosquito control practices in Delaware, dating
back essentially to the late 1950s and before, many developed areas of the
First State (e.g. downtown Dover!) would more than occasionally experience
severe mosquito infestations having landing rate counts of biting adult
mosquitoes from 20-50 per minute, which through nuisance or annoyance greatly diminishes an area’s quality-of-life. A landing rate count of only 1-2 mosquitoes
per minute in your backyard on some balmy summer evening would translate within
a half-hour into 30-60 bites covering exposed parts of your body, clearly not a
desirable situation. Imagine how long
you’d stay outside in a setting of 20-50 bites per minute! And as more-and-more people move into
Delaware, and as they increasingly seem to all want to live in areas near
coastal wetlands or wet woodlands, demands for our control services (and upon
our program’s limited resources) only continue to escalate.
In addition to personal discomfort from such infestation levels,
uncontrolled mosquito populations can also have significant adverse impacts to local economies based upon tourism,
outdoor recreation, or animal husbandry, along with undesirable effects on your
neighborhood’s property values. As such,
our delivery of mosquito control helps to maintain a good quality-of-life and
robust economy throughout many areas of
Another major reason for controlling mosquitoes is their well-known potential
for carrying and transmitting diseases,
not only just to humans, but also to our domesticated animals such horses or
dogs. In Delaware today, we are
concerned with encephalitis viruses such as Eastern Equine Encephalitis (EEE), an alphavirus, which when either
humans or horses contract EEE can often be fatal, with special concern for
children and elderly; those who recover are often left with lifelong
debilitating symptoms – there is a EEE vaccine for horses, but not for humans. Fortunately, the occurrence of EEE is
relatively rare, and the Mosquito Control Section works hard to keep it this
way. West Nile Virus (WNV), a flavivirus, is a recently-introduced
Many Delawareans are probably not aware that so-called “tropical”
diseases, such as yellow fever (a
flavivirus) or malaria (a protozoan
parasite, Plasmodium spp.), were at
one time quite common in the southeastern United States, including areas as far
north as Delaware and even into New England.
A yellow fever outbreak in
With over 20% of
3) What kinds of insecticides are used, and when do
you use them?
A variety of insecticides are needed for performance of modern mosquito
control, and are used only when and where other types of control are not
practicable to do (see FAQ #4 below for a discussion of alternative control
methods to insecticide use). The
Mosquito Control Section utilizes insecticides as an important component of its
Integrated Pest Management (IPM)
program. Please note that IPM does not
mean that no insecticides can be used (as sometimes popularly misunderstood),
nor that insecticides must be only a minor part of an IPM control
strategy. Rather IPM refers to making
the best use of a combination of the most practicable control methods at our
disposal to deal with real world situations, to treat pest problems only
when and where they occur, doing so in the most efficacious,
environmentally-compatible, cost-effective manner possible.
There are two basic types of mosquito control insecticides – larvicides for control of larval or
immature mosquitoes, selectively applied to wetland areas and other aquatic
breeding habitats; and adulticides
for control of flying or resting adults, selectively used primarily in upland
areas where adults on-wing are causing problems. All insecticides that we use are registered
by the U.S. Environmental Protection Agency (EPA) for the types of applications
we perform. Insecticide applications
are done only when and where we have indications of unacceptable or intolerable
numbers of mosquitoes undergoing larval development or already on-wing, and
these mosquitoes must also be of the dozen or so species that are particularly
problematic biters of humans or other mammals.
Indications of when and where spraying is necessary are derived through an extensive and intensive field
surveillance/monitoring effort, involving a variety of detection efforts –
e.g. larval sampling in wetlands and other breeding areas (“dipper counts”);
landing rate counts (i.e. numbers of adult female mosquitoes that land on a
field inspector per minute); nightly adult light trap collections; detection or
occurrence of disease viruses or other pathogens within mosquitoes themselves
or in sentinel organisms; the numbers and patterns of public complaints
received; etc. No spraying is done
unless threshold criteria (involving subjective or objective measures) are
exceeded for these various indicators, and quite often a combination of
indicators is used.
Spray applications might be aerially done using fixed-wing aircraft or helicopters for larvicides or adulticides, or might involve truck-mounted applications of larvicides (via “pump truck”) or adulticides (via “foggers”). Larviciding to treat small areas or container habitats is sometimes done on-foot, using backpack sprayers or hand-tossed formulations. The choice of what type of insecticide to use and its mode of delivery is dependent upon the type of species to be controlled, the life stage(s) targeted for control during any particular brood, and the type of habitat or location where spraying will occur. Since in almost all cases larviciding involves less direct exposure of people to insecticides than adulticiding, whenever we have to spray we usually always prefer to try to larvicide first, and turn to adulticiding only as a last resort.
The timing for when we apply our insecticides, and for how the applications are done, is also determined (and quite often complicated) by weather conditions (e.g. air temperature, wind speed and direction, humidity, rainfall), all which must be considered in our performing appropriate and allowable treatments. All of our public spray announcements have the condition of “weather permitting.” When dealing with saltmarsh mosquito larval control, we must also take into consideration daily tide stages and the monthly lunar tide cycle too. In doing our spring woodland-pool species control, we are often racing against the calendar to complete our aerial larviciding before forest canopy leaf-out prevents effective spraying of our products. And you can probably readily envision the many problems we face when trying to treat urban or congested areas – think about all the things you might have to deal with when trying to operate a truck-mounted adulticide sprayer as one encounters crowds of people along the streets, traffic jams, or detours, during an effort to prescriptively spray-out uniform amounts or concentrations of an insecticide – this is one reason why you might see any inner-city ground adulticiding until 3:00 am in the morning.
Our frontline larvicides are Bti
(VectoBac, VectoLex, Teknar or Aquabac, which are all bacterially-produced
insecticides) and methoprene (Altosid, a juvenile growth hormone mimic), both
which can be applied in liquid or granular formulations. Bti
is primarily effective against earlier immature stages, and seems to work
better (or at least more consistently) for control of freshwater species (e.g.
spring woodland-pool breeding species) than for saltmarsh mosquitoes of the
open marsh. Methoprene is best used against later immature stages, and is
effective against both freshwater and saltmarsh species, but still has to be
applied before the larvae pupate. Both Bti and methoprene are state-of-art, third-generation pesticides that are
classified as “biorational” products.
Another type of larvicide available to us is temephos (Abate, an organophosphate
second-generation insecticide), which we use in liquid formulation for control
of freshwater mosquitoes in roadside ditches, or in granular form for saltmarsh
mosquito control in areas of heavy wetlands vegetation – temephos is effective against all larval stages. A final type of larvicide that we
occasionally use are monomolecular surface films (Agnique
or Arosurf), to treat larvae or pupae, usually hand-applied to
container-breeding or other types of confined freshwater habitats.
Our frontline aerially-applied adulticide to
treat problem mosquitoes on-wing is naled (Trumpet or Dibrom, an
organophosphate), which is equally effective against freshwater or saltmarsh
mosquitoes. [Naled is used by many mosquito control programs around the country;
as is another organophosphate adulticide, malathion (Fyfanon or Atrapa)
which the Section currently does not use.]
Another category of adulticides that we use is
synthetic pyrethroids, which seem to be more efficacious when applied by
truck-mounted sprayers (“foggers”) than by aircraft. The primary synthetic pyrethroid that we use
for ground “fogging” is sumithrin (Anvil), although
alternatives such as pyrethrin (Pyrenone), permethrin
(Permanone, Biomist, Aqua-Reslin) or resmethrin (Scourge) are also
available and used around the country.
Unfortunately, in comparison to naled,
synthetic pyrethroids don’t seem to be as efficacious against saltmarsh mosquitoes,
nor seemingly as good for aerial applications.
It is important that we have this diversity of
mosquito control insecticide products to call upon, since we need such
versatility in dealing with different target species, different brood or life
stages, different types of habitats to treat, varying weather conditions to
work under, special concerns for avoiding certain types of potential non-target
impacts, etc. We must also take steps
not to overuse any one of these products against our local mosquito
populations, in order to avoid or at least postpone the appearance of insecticide resistance (which undercuts
effective control) among our target species.
Insecticide resistance can arise through overly-aggressively targeting
certain species or life stages with but a single product, such that the small
percentage of any species population that might be naturally resistant to
whatever insecticide is being used then greatly multiplies because of its
essentially insecticide “resistant” or immune nature, to then dominate future
generations of the target species (for which we would then have one less
control tool that will work). As such,
for avoidance of resistance problems alone, it is important to be able to use and
rotate a variety of insecticides in our control work, and to also adopt new
insecticides whenever possible and appropriate.
4) Why do you have to use
insecticides at all? Aren’t there better
ways to achieve control? What other
approaches do you use?
Modern insecticides are but a tool that mosquito control professionals
can call upon in their IPM programs to help reduce or suppress intolerable
numbers of mosquitoes. As with all pesticides, there is always the chance in using an
insecticide that something might go wrong, or that a product’s use might have
unintended consequences that are not foreseen. However, the development process for modern
insecticides, given the extensive and intensive product review and registration
process that is conducted by the U.S. Environmental Protection Agency (EPA),
helps to ensure to the extent practicable that today’s use and application of
modern mosquito control insecticides is done as safely as possible, and that
any risks from adverse impacts to humans, wildlife or environment are extremely
minuscule. In terms of risk-benefits,
problems that mosquitoes cause for quality-of-life, public health or local
economies are far greater issues than the deminimus or very small risks that
might be associated with infrequent exposure to mosquito control spraying. More information about the safety of our
mosquito control products is provided in FAQ #5 below.
Having said this, the Mosquito
Control Section still prefers wherever practicable to use non-insecticide
control methods, since the exceedingly small risks that might be associated
with mosquito control spraying obviously go to zero if or where no spraying is
done. The most practicable alternatives
to using insecticides are a category of control methods collectively called source reduction, which through various
approaches either eliminate mosquito-breeding habitats, or somehow control
mosquitoes in their pre-emergence larval stages. One example of source reduction was mentioned
in FAQ #1 above, whereby property owners practicing good water sanitation around
their homes or businesses can measurably help to reduce mosquito-breeding
habitats. Public education and
cooperation is the key to this type of domestic water sanitation source
reduction.
However, many breeding habitats are too large, or in too remote or
inaccessible areas, for private citizens to be able to provide much help for
source reduction, which is where the Mosquito Control Section must then
act. Because of the long flight ranges
of saltmarsh mosquitoes and the remote wetland areas where these mosquitoes are
often produced, the Mosquito Control Section devotes a lot of its efforts to
managing saltmarsh habitats for reduction of mosquito breeding, including using
a source reduction technique known as Open
Marsh Water Management (OMWM). The
OMWM method selectively excavates small, shallow ponds and ditches in
mosquito-breeding areas of the high saltmarsh, which in doing either eliminates
egg-deposition habitats for saltmarsh mosquito species (which require moist
muds for their egg-laying), and which provides permanent water habitats for
resident native fishes (e.g. killifishes, Fundulus)
that are voracious predators upon mosquito larvae. All OMWM wetland alterations are done under
regulatory oversight by the Delaware
Mosquito Control Advisory Committee (DMCAC), consisting of four federal
agencies (Army Corps of Engineers, U.S. Environmental Protection, U.S. Fish and
Wildlife Service, National Marine Fisheries Service), three DNREC agencies
(Division of Fish and Wildlife, Wetlands and Subaqueous Lands Section, Delaware
Coastal Management Program), and the State Historic Preservation Office.
Most OMWM alterations are not directly connected to daily tidal flows,
such that OMWM ponds and ditches do not typically drain or dewater marsh
surfaces of standing water bodies, nor excessively lower the marsh subsurface
water table. This helps to control
saltmarsh mosquitoes without insecticides in a manner that avoids the
previously detrimental ecological impacts of the old parallel-grid-ditch system, which were open tidal ditches
geometrically spaced about 150-feet apart, traversing much of Delaware’s tidal
wetlands (in both breeding and non-breeding areas), with intention to drain or
dewater marsh surfaces. The
parallel-grid-ditches were constructed by the Civilian Conservation Corps in
the 1930’s, and these ditches were periodically recleaned of accumulated
sediments into the 1970’s. The open,
tidal parallel-grid-ditches had adverse impacts on saltmarsh habitats by
draining many shallow ponds and mudflat areas that were valuable fish and
wildlife habitats, and in some areas through spoil deposition (from the ditch
excavations), or by lowering of the subsurface water table by low tide
drainage, caused undesirable vegetation changes (e.g. incursions of marsh
shrubs or reed grass, Phragmites, in
ditched areas). Furthermore, while the
old parallel-grid-ditches helped to reduce mosquito production in some areas,
they were still not effective enough to achieve the desired level of control
needed in many locations, because mosquito-breeding habitats between the
parallel-grid-ditches (particularly the small “pothole” depressions) were not
drained.
Today’s modern OMWM technique
avoids these problems by using specialized excavation machinery that does not
cause excessive increases in marsh elevations from spoil deposition (e.g. a
rotary excavator, which broadcasts excavated spoil as a thin slurry over the
marsh surface); by OMWM system design and excavated alterations that do not
lead to excessive lowering of the subsurface water table; and by actually
satisfactorily controlling almost all mosquito production in areas that are
treated. Furthermore, the installation
of OMWM systems as overlays upon old parallel-grid-ditch networks helps to
restore standing surface waters to the marsh valuable as fish and wildlife
habitats, thereby restoring some lost wetland values and functions. Unfortunately, OMWM cannot be used everywhere
saltmarsh mosquitoes breed, because of factors like not having marsh landowner
permission or cooperation (for a variety of reasons); by site access
considerations for heavy machinery; by other environmental considerations (e.g.
leaving intact the relatively little saltmarsh acreage in Delaware, and within
the entire Northeast too, that still remains undisturbed by any type of
alteration, such as what is found at Bombay Hook National Wildlife Refuge); or
by project size or project scale (it is not usually cost-effective to treat
small marsh areas or small amounts of breeding with OMWM, especially when there
are so many larger areas of the State’s coastal wetlands still needing OMWM
treatment). Wherever there are
problem-breeding saltmarsh habitats that cannot be treated with OMWM, then
judicious use of insecticides must be employed; and because of the scale of the
problems encountered in saltmarshes, usually treated through aerial spraying by
fixed-wing aircraft, and sometimes if more localized treated via
helicopter. Installing OMWM systems is a
labor-intensive, capital-intensive undertaking, but in the long-run is usually
more cost-effective than continual periodic treatments with insecticides.
Other types of source reduction practiced by the Mosquito Control Section
include management of tidal flows and
marsh water levels to discourage or control mosquito production in coastal wetlands impoundments, which on
federal, state and private lands total over 10,000 acres of Delaware’s
>90,000 acres of coastal wetlands.
These impoundments are areas of marsh that are diked-off with levees, whose
interior waters are then managed by various types of water control structures
for multiple environmental goals and objectives, including flood prevention,
stormwater management, waterfowl production and hunting, habitats for wading
birds and shorebirds, estuarine fish nursery areas, crabbing and fishing,
saltmarsh mosquito control, nature study, canoeing, etc. Along with our other colleagues in the
Division of Fish and Wildlife, the Mosquito Control Section plays a major role
on State lands in helping to maintain and manage these valuable wetland
units.
It is not always possible (nor desirable) to manage tidal exchanges or
marsh water levels in these impounded units for only one purpose, so sometimes
it is not always possible to achieve satisfactory mosquito control in
impoundments through water management alone, which might then necessitate some
judicious insecticide spraying (using larvicides), usually with a helicopter,
but sometimes in more expansive impoundments by fixed-wing aircraft. Shallow
ponds and ditches can also be excavated within impoundment interiors to help control mosquito production,
but these features are often difficult to maintain because of the
unconsolidated nature of many impoundment bottoms, which then tend to rapidly
fill-in any excavations that were made, routinely requiring
re-excavations. However, where still
cost-effective to routinely do this periodic re-excavation, and in order to
reduce insecticide use, the Mosquito Control Section is committed to
undertaking this impoundment source reduction work.
Another type of source reduction performed by the Mosquito Control
Section involves the stocking of
mosquitofish (Gambusia) in
freshwater mosquito-breeding habitats, such as in stormwater management basins
that are often associated with subdivision developments or highway projects, or
in small natural or ornamental ponds.
Unfortunately, fish survival cannot always be ensured in many of these
locations, because of water volume or water quality problems, and often because
of too cold overwintering temperatures, eliminating the stocked fish. The rearing and distribution of mosquitofish
is also very labor intensive.
Additionally, stocking mosquitofish in some natural areas cannot be done
because of concerns about adverse impacts to native fishes through
interspecific competition, or because of concerns about predatory impacts upon
amphibians of special concern.
Unfortunately, there is not a freshwater “OMWM-equivalent” method for
dealing with non-tidal mosquito production problems found in freshwater
wetlands or wet woodlands. When source
reduction using mosquitofish cannot be employed, then these types of habitats
must be treated with insecticides (primarily larvicides), often done by hand or
ground-application equipment. Finally,
in regard to source reduction approaches for stormwater management basins,
there are considerations in a basin’s design and construction, and in
management of its water levels, that will help to reduce mosquito production,
all which are encouraged to be followed by developers or other agencies.
Other types of source reduction are possible, but unfortunately their
overall effectiveness is usually not satisfactory, or is often not up to what
one is sometimes led to believe will occur.
For example, encouraging on your property through nesting structures
colonies of purple martins (via
elevated, multi-chambered “houses”) certainly cannot hurt, but scientific
studies have shown that when mosquito production is evenly moderately high, and
the production problem emanates from expansive nearby areas, that these birds
are really not very effective at all in reducing mosquito infestations, even
for achieving the local relief that might be desired. Part of the problem stems from purple
martins being actively flying and feeding during daytime only, whereas many
mosquito problems are most pronounced during twilight periods or dark (the
birds might have more of a beneficial effect here on controlling daytime biting
greenhead flies, deer flies, or biting gnats).
If one is looking to encourage airborne predators to help combat local
mosquito problems, building bat houses to
encourage colonization by night-time flying bats is probably more effective;
but then one has to also tolerate having bats around, which aesthetically some
people (especially neighbors) might not like, not to mention concerns about
bats carrying and possibly transmitting rabies.
The electronic “zappers” that
are so popular in some neighborhoods have been scientifically shown to really
be of very little value in controlling mosquito populations, and have also been
documented to have adverse impacts on non-target insect species. Commercial
mosquito collection/killing traps, some which are rather sophisticated with
lights, fans and sources of carbon dioxide or other attractants (e.g. octenol),
might be marginally effective in some localized situations (e.g. Mosquito
Magnet, Mosquito Deleto). However,
because of their relatively high expense (several hundred dollars) and limited
areal effect (supposedly about ½-acre), these devices are really not very
effective for contending with larger-scale problems, and hence not very
practicable to consider using for large-scale needs or operations. But this is not to say that these devices
cannot provide some very localized relief in your
backyard setting, if not in terms of a noticeable drop in the numbers of
mosquitoes that are biting you, then perhaps at least for psychological relief,
in that you’re at least doing something to help kill some skeeters.
Finally, it should be noted that the mosquito control profession is
always on the lookout for more efficacious, cost-effective control methods that
also lessen any non-target impacts.
Various alternatives have been proposed or arisen, and many have been
tested, such as the introduction in the field of irradiated, sterilized adult
male mosquitoes or genetically manipulated mosquitoes to try to lessen
reproductive potential; the introduction of fungi, protozoans, nematodes or
other microbial pathogens to infect and kill mosquito larvae; the introduction
of mosquito species that as larvae prey upon other mosquito larvae (“cannibal”
mosquitoes); etc. However, while these
alternatives might look good in theory or in the lab, in terms of their
performance in the field, or in regard to their practicability for large-scale
operations, they have so far not been satisfactory. To this category might also now be added
trying to use ultrasonic sound waves to physically kill larvae by rupturing air
pockets or bladders within their bodies, which shows some promise in limited
size or tightly confined aquatic habitats (e.g. Larvasonic for treating storm
sewer catch-basins), but awaits further research in terms of control efficacy,
non-target impacts, and practicable utility.
In collaboration with academic researchers and product manufacturers, we
are always seeking “new chemistries” or other improved technologies for
potential adoption for our control toolbox (e.g. insect growth regulators,
ovipositioning repellents, algal- or plant-produced toxins, population
autoinhibitors), perhaps leading to yet another generation of further improved
insecticides.
More information about the Mosquito Control Section’s options and choices
for dealing with mosquito production problems can be found on the Section’s
Internet website at www.dnrec.state.de.us/fw/mosquito.htm,
particularly on our Section’s Welcome webpage, in our Spray Policy, and in our
description of OMWM.
5) Are mosquito control
insecticides safe to use, and should I be concerned if I’m exposed to spraying?
The Mosquito Control Section only
uses insecticides that are registered by the
The hazardous warning statements and other safety precautions that appear
on pesticide product labels are
often a source of concern to folks who do not understand their context or
applicability, and as such sometimes present public relations problems for our
program. It must be kept in mind that
the EPA-approved warning or precautionary language on product labels is
targeted primarily toward avoiding having a human or other type of organism
have direct exposure (through ingestion, inhalation or dermal contact) to
full-strength, undiluted products, as well as what to do if such exposure has
occurred. The product label language is
also of primary utility to the spray applicators themselves, who most
frequently might routinely or accidentally have such exposures. It must be understood that the final
application of insecticides during our routine spray operations is always done
via a mode of delivery approved by the EPA, with applications made at
concentrations that are either always very diluted or at Ultra-Low Volume (ULV)
rates, and which are not done very frequently for any given site. As such, in real world use, these
application conditions have allowed the EPA to scientifically conclude that
when all product label language and instructions are followed, use of our
mosquito control insecticides “poses no
unacceptable risks to human health, wildlife or the environment.”
As part of the Delaware Department of Natural
Resource and Environmental Control (DNREC) within the Division of Fish and
Wildlife, the Mosquito Control Section is of course very concerned that there are no unacceptable non-target
impacts (to humans or fish and wildlife) whenever we must conduct our spray
operations. The first generation of modern insecticides
arose in the 1940’s, which included long-lasting products like chlorinated
hydrocarbons (e.g. DDT), and whose environmental persistence unforeseeably led
to problems for some higher-order consumers (e.g. egg-shell thinning and
reproductive failure in certain birds-of-prey), has now been replaced by much
shorter-lived second and third generation modern insecticides. This is not to say that all concerns about
the potential for yet unknown or poorly-understood non-target impacts, even
when products are used in strict accordance with all EPA-approved label
instructions, have completely faded for all modern insecticides – e.g. in the
last several years concerns have arisen about potential endocrine system
effects (“endocrine disrupters”) associated with certain types of pesticides
(or their accompanying synergists or other additive ingredients), which still
bear objective tracking and further scientific inquiry. However, it is fairly safe to say that the
benefits of judiciously using modern
pesticides to help meet important societal needs (e.g. mosquito control, rodent
control, disease prevention, crop production, food storage, timber production,
structural building protection, landscaping needs, etc.) far outweigh any known
risks for EPA-registered products, since the EPA’s product registration or
re-registration process over the past 30 years has taken almost all
previously-used “bad actor” pesticides off the market, and has not knowingly
let any new “bad actor” products into the market.
As such, in today’s era of heightened environmental concerns, almost all
remaining potential problems for human health or non-target organism impacts
caused by mosquito control spraying primarily arise from human mistakes or
application errors that might be made in the rate of application (e.g. spray
equipment calibration errors), the timing or place of application (e.g.
accidentally repetitively swathing the same area), or with other operational
aspects of performing spraying (e.g. spraying when too windy), all which can be
readily avoided when product label instructions are scrupulously followed, and
applications are made by dedicated, trained professionals. Mosquito Control Section staff and our
contractual spray applicators are all knowledgeable professionals certified by the Delaware Department of
Agriculture for using insecticides in proper and safe manner.
In closing our comments about this FAQ, it should be noted that a very
small segment of the public might be hyper-
or chemo-sensitive to the insecticide products that we use (as well as
perhaps also adversely reactive to other types of chemicals in the
environment), particularly our adulticides for which people are much more
likely to be exposed. Such hyper- or
chemo-sensitive individuals might experience allergic-like reactions to our
spraying, perhaps consisting of irritated eyes or throat, sneezing, coughing or
other mild symptoms. If you experience
such discomfort during or immediately after a mosquito control spraying, then
you are unfortunately one of the very few who might well be concerned about
exposures to our treatments. In the
unusual event that you are experiencing adverse health effects following
insecticide application, you should consult your personal physician or seek
other medical care. You will also find
information in FAQs #6 and #7 below that should help you (and us) better
contend with your individual problem, including how to avoid exposures to our
spraying.
More information about the insecticides we use and their safety can be
found on the Mosquito Control Section’s
website at www.dnrec.state.de.us/fw/mosquito.htm. The
phone number to contact the Section’s
administrative headquarters in
6) How
can I found out when and where mosquito control spraying might next be done?
If you want to know about when a
mosquito control spraying might occur in your area, for whatever reasons or
interest you might have, you can receive our spray announcements
automatically on your home or business computer (via e-mail notification over
the Internet) by subscribing to our listserver
at www.dnrec.state.de.us/DNREC2000/admin/maillists/maillists.htm. Because of many complicating factors
in planning, preparing and performing our often daily spray operations (such as
varying locations or intensities of mosquito problems that often aren’t known
by our field inspections until the last minute, but which then need rapid
response, or our having to contend with fluctuating wind or weather
conditions), the most advance notice that we can routinely give might be up to
24 hours lead time, but sometimes it might be as short as only 4 hours notice
(this short lead time obviously negates us being able to give any effective
advance notice of our spray plans in daily newspapers). You can also directly electronically access
the Mosquito Control Section's updated advance spray announcements at your
convenience, by contacting the Section’s
website at www.dnrec.state.de.us/fw/mosquito/ksspray.pdf for
If you don’t have a computer
or lack access to the Internet, or if you prefer not to use such electronic
approaches, you can listen to one of several radio stations that as public
service announcements often broadcast Mosquito Control's current plans for
upcoming sprays. On a daily basis we
submit our spray announcements to over 12 radio stations around the state, but
unfortunately we have no control over if, when or how often these stations
might run our spray notices.
We also have a toll-free phone line at 1-800-338-8181 that you can call as
often as you like, to listen to our taped spray announcements that are
updated daily.
If you live within an
incorporated city or town, by our Spray Policy we routinely notify designated
local officials in advance of almost all of spray operations occurring within
city or town limits. In turn, municipal
officials might then try to provide further advance spray notifications to
their constituents, so you might want to check with your local city or town
officers.
Finally, with
the terrorism events of “9-11” (September 11, 2001 in New York City and
Washington, D.C.) now causing much heightened concern about many security issues, it is important
for the public to know that when they observe our low-flying aircraft or “fog
trucks” going about our business of spraying mosquitoes, “it’s just us” doing
what we’re charged to do. In order to
help accomplish this awareness for the public and other agencies too, we now
routinely also inform the Delaware Emergency Management Agency (DEMA) about our
spraying operations.
7) If I don’t want to be exposed to mosquito control
spraying, what steps might I take?
No matter what the scientific evidence indicates about the safety of the
Mosquito Control Section’s using modern mosquito control insecticides, nor no
matter what learned professionals might say, there will probably still be
people who for whatever reasons will still want to avoid having any exposure to
our insecticides (and yet somewhat ironically, many of these same people will
also want mosquito relief, if not openly seeking such, at least not objecting
to such when it is achieved). But such
desires for no spray contact or exposure are by no means insincere or
completely unfounded. From a medical
standpoint, there is a very small segment of the public who might be hyper- or chemo-sensitive to exposure
to some of our insecticides (particularly for some of our adulticides, for
which exposure is much more likely than having contact with our larvicides), resulting in
allergic-like reactions for these people that might involve eye or throat
irritation, sneezing, coughing or other symptoms – e.g. some people with asthma
might be more sensitive here. Despite
what the EPA has determined regarding the overall safety of our mosquito
control products for a vast majority of the public, we recognize that there are
a few individuals who might have mildly adverse physical reactions to the
products we use, and as such we attempt to accommodate these individuals the
best we can, while still delivering quality-of-life and mosquito-borne disease
prevention services for the vast majority of the public.
We also try to accommodate to the extent practicable, in keeping with our
best serving the needs of the general public, those organic gardeners or produce growers who by the conditions of how
they want to grow or market their agricultural products try to do so in as
pesticide-free manner as possible. And
through the Delaware Department of
Agriculture and the Delaware
Beekeepers Association, we also have a working agreement and notification
protocols with commercial beekeepers,
whereby through some mutually proactive measures they can be kept appraised of
our pending spray operations, to help avoid any adverse impacts to their
beehives or colonies.
Individuals who for whatever reasons are still concerned about exposure
to the insecticides applied by the Mosquito Control Section, particularly for
adulticides, can take some common-sense steps to avoid direct exposure to our
spray applications, such as temporarily leaving an area about to be sprayed, or
by remaining indoors and closing doors and windows, and shutting off window air
conditioners, during and immediately after insecticide spraying. The general
times and locations for knowing about the Section’s pending spray operations
can be determined through various media devices and other means as described in
FAQ #6 above.
The Section will also consider special requests to
establish a “No-Spray Zone,” where
mosquito control adulticides (insecticides applied to control adult mosquitoes)
are not applied to your location.
Decisions on granting No-Spray Zone requests are made by the Mosquito
Control Section in consideration of a citizen’s or resident’s stated purpose for making such a
request; whether such a request can be practicably accommodated by our
application equipment and within our application operations; and whether not
spraying your location will unreasonably deny your neighbors or your community
of their desired mosquito control services.
In regard to the last factor, our
possibly granting a No-Spray Zone will result in no mosquito control treatment
either for your neighbors or other properties within several hundred feet of a
No-Spray Zone’s epicenter, which then obviously in some situations could
become contentious, and lead to some “neighbor” problems not always easy to
resolve.
By our Spray Policy, requests for No-Spray Zones by
citizens or residents living within an incorporated municipality (city or
town), applicable only to use of adulticides, must be made to the Mosquito Control Section by a municipal official (on
their constituent’s behalf), with the municipality then obviously being in
concurrence with such a request, and with the municipality also providing all
the information required for the Mosquito Control Section to make its decision. As such, a citizen or resident of a
municipality wishing to have a No-Spray Zone established around his/her
residence or property should first contact an appropriate municipal official
and obtain the municipality’s support or concurrence. Conversely, in unincorporated areas, citizens
or residents wishing to request a No-Spray Zone, again applicable only to use
of adulticides, may do so by directly contacting the Mosquito Control
Section. In all cases for unincorporated
areas, only the actual property owner
can make the No-Spray Zone request (i.e. not a renter, tenant, vacationer,
visitor, etc.).
Information requested to be provided in a No-Spray
Zone request, whether coming from a municipal official for a citizen of a city
or town, or from property owner themselves in unincorporated areas, is pretty
straight-forward, involving items such as name, address, and phone number of
property owner making the request; purpose for making the request; description
and map showing property’s location; names, addresses and telephone numbers of adjacent
property owners; whether the request is for aerial spraying, ground spraying,
or both; etc. It is necessary to
complete a No-Spray Zone request application each-and-every year that such
consideration is desired. This is
because a property’s ownership might change from year-to-year,
or the desire or necessity for having a No-Spray Zone might also change from
year-to-year, and as such there will be
no automatic carryover of a previous year’s request for a No-Spray Zone. It is the responsibility of the municipality
or individual desiring a No-Spray Zone designation to provide such notice to
the Mosquito Control Section in timely manner on an annual basis, which if at
all possible should be made by March 1 of each-and-every year when such
consideration is desired.
Based upon the information received, the Mosquito
Control Section will then make an approve/no-approve decision within a few
weeks of receiving the completed application form. In almost all cases, particularly when a medical case of hyper- or
chemo-sensitivity is involved, the Section will try its utmost to
accommodate the No-Spray Zone request, weighing the good that granting such a
request will do for the individual making the request, versus what might be
lost in the way of quality-of-life or public health threats to others (in our
not being able to treat adjacent or nearby properties). This is by no means always an easy decision
to make. And finally, in event of a declared human health emergency caused
by outbreak of mosquito-borne disease, the Section reserves the right to cancel any No-Spray Zone
status that it might have granted, and to proceed with undertaking whatever
spraying might be necessary to protect the general public’s health during a
disease outbreak. However, the Section
will attempt to provide advance notice of such cancellation to those people who
might now be having their No-Spray Zone status cancelled or temporarily
lifted.
Additional information on how to request a No-Spray
Zone can be obtained by contacting the Mosquito
Control Section in
8) What personal protection measures can I take to
help avoid mosquito bites?
Probably the simplest action whenever possible is to try to avoid areas or times where mosquitoes are most active, such
as near coastal marshes, wet woodlands or other swampy locations. But as was pointed out in FAQ #2 above, many
mosquito species are long-distance fliers, and as such will often come find
you.
If you happen to live in a mosquito-prone area or have occasion to visit
such, then your next line of defense is try to stay indoors if possible during peak mosquito activity, which
for many species is near dusk, during the evening or night, and into early
morning. Using and keeping your door and
window screens in good repair is an obvious
measure. [In many areas, folks who are
fortunate enough to have screened-in porches are very grateful they do!] Wherever mosquitoes might still be a problem
inside a residence, the old practice of using mosquito bed-netting could be
resurrected. However, some particularly
troublesome species, such as the common saltmarsh mosquito or the Asian tiger
mosquito, are also very active daytime biters -- since many people must be
outside and active during the day, the avoidance measures above don’t have much
application.
The type of clothing you wear can also help to reduce mosquito
bites. If it is not too hot or
uncomfortable, consider wearing
long-sleeve shirts and pants when outside.
Wearing light-colored clothing
also helps (in particular, avoid red colors).
If the mosquito infestation is truly bad and you must remain outside,
you might want to consider using a fine-mesh head net or a “shoo-bug jacket.” Using yellow light bulbs for outside lighting
might also help.
Avoiding outside activities that require a lot of exertion and hence
generate a lot of carbon dioxide, a powerful natural mosquito attractant, is
also advisable in mosquito-infested areas.
Physical exertion also produces body heat and lactic acid in sweat,
which are also attractants for mosquitoes.
Also do not use strong-smelling perfumes or cologne, nor fragrant soaps,
shampoos or hairsprays.
Probably the most common remedy for contending with having to work, live
or recreate outdoors in mosquito-infested areas is the use of some type of chemical repellent. Scientific studies have shown that by far the
most effective types of repellents are commercially-available, over-the-counter
products that contain the chemical DEET (e.g.
OFF, Cutter, Muskol, Ben’s, 6-12, Sawyer).
Other types of repellents are also available, including certain brands
of cosmetic creams that might have some repellent effect (e.g. Avon
Skin-So-Soft), or various “natural” oils, spices or other extracts (e.g.
eucalyptus oil, lemongrass, pennyroyal, allspice, bay, camphor, cinnamon,
citronella, geranium, lavender, nutmeg, peppermint, pine, thyme). However, most scientific evidence shows them
to be of comparatively little or only marginal effectiveness – nonetheless, the
bottomline here is to use whatever you think or “know” works best for you.
There is a very small percentage of people who
might have some adverse health reactions to high concentrations of DEET (e.g.
50-100%), so as a general rule it is recommended that adults use repellents containing a DEET concentration of 30% or less,
and for children the concentration should be 10% or less. Do not
use DEET on infants under 2 years old. From
the standpoint of health precautions, it is better to more frequently apply
formulations with lower DEET concentrations, versus infrequently applying
formulations with higher DEET concentrations.
Be sure to follow all application instructions on a repellent’s label.
Another type of chemical defense is to spray clothing with permethrin, a
synthetic pyrethroid (e.g. Permanone), which actually functions here as both an
insecticide and a repellent, and is also used to help prevent tick
problems. If permethrin is used, it
should be applied only to clothing and never directly to skin, and all
instructions for use must be closely followed.
Finally, there are other measures that you can take
around your home or property to reduce mosquito bites that were discussed in
FAQ #1 above (i.e. practice good water sanitation),
as well as perhaps taking some measures discussed in FAQ #4 that have much
lower abatement effects (e.g. purple martin colonies, bat houses, electronic
zappers, mosquito collection/killing traps) -- at the risk of repetition, the
true effectiveness of these latter methods is quite dubious. Some people also find that burning certain
materials (e.g. citronella candles,
sticks or coils) to be of some limited help in keeping mosquitoes away from
their personal airspace. It is known
that Native Americans tried such smoky approaches (e.g. “smudge pots”) to
achieve some skeeter relief (if they could stand the smoke and smell), but
during seasons of peak mosquito activity some tribes were also in the smart
habit of relocating their villages to less mosquito-prone sites. For most modern Americans this type of ready
residential movement is no longer an option, which is part of the reason for
our Section’s existence and mission.
9) What do I do if I find a sick/dead wild bird that
might have
As discussed in FAQ #2 above, the recent arrival in
First, a determination (to the best of one’s
ability) should be made as to what species of bird you have. Crows, blue jays and birds-of-prey
(hawks, eagles, falcons or owls) have shown to be the most susceptible species
to WNV, and are therefore the primary bird species collected. Of these species,
crows seem to be the most commonly affected and reported. Crows can be identified by their large size
(approx. 12-16” in total length, or about the size of a football), matted black
color (even their eyes), large beak (1-2” long), etc. Blue jays are smaller than crows, with mostly
blue, black and white feathers.
Birds-of-prey can be recognized by their large, sharp claws and hooked
beaks. These are the only bird species (when found singly or in numbers less than
five) that should be reported to the
Mosquito Control Section. However,
citizens should feel free to report occurrences of 5 or more specimens of any
bird species.
Secondly, it should be determined if the bird has been dead less than 24 hours. Current testing techniques require that specimen birds be fresh for accurate virus detection. A relative scale such as “the bird was not in your yard when you left for work in the morning, but was there when you returned home in the evening” would be fine for knowing the bird is probably less than 24 hours old. Dead birds that are infested with maggots, or which have deeply sunken eyes or whose feathers are in poor condition, are specimens that have probably been dead for too long for any worthwhile analyses.
After the above criteria have been met, the bird
should be covered if possible by a bucket, box, trash can lid, or other type of
covering to protect it from further degradation by sunlight, direct heat,
flies, scavenging animals, etc. As a
general precaution when handling any dead animal, it is recommended that you do not have any bare-handed contact or
otherwise directly handle the bird, even though from what is known about
WNV you could not contract the disease by doing so. [To date, there has been no indication of any
animal-to-human or person-to-person transmission of WNV.] A call should then be placed to the Mosquito Control Section under the
following guidelines. If the bird is
found in New Castle County, call 323-4492 during weekday hours between
10) What are human health problems/symptoms when a
mosquito-borne viral disease
is contracted? And what is the probability of my becoming
infected or sick?
As mentioned in FAQ #2 above, the primary
mosquito-borne disease concerns in
A large majority of people infected with WNV apparently might never know
they’ve been infected, in that they feel no adverse effects whatsoever (i.e.
they’re asymptomatic), or they have only mild overall discomfort that’s not
severe enough for them to seek any medical attention; however, this is
relatively benign reaction is rarely the case with EEE.
When symptoms are first felt for either WNV or EEE, early indications of
infection include headache, mild fever, body aches, malaise, and occasional
swollen lymph glands, all which are flu-like symptoms (as such, if you live in
an area where mosquitoes are abundant, you might want to be somewhat suspicious
if you or someone you know comes down with a “summer flu,” and seek medical
care). These early symptoms might occur
from 7-10 days after receiving an infectious bite, and might come on slowly or
quite suddenly. [The most probable time
of year in
Since arboviral encephalatides are
viral diseases, trying to use antibiotics to treat WNV or EEE is not effective,
and no effective antiviral drugs have yet been discovered. For full-blown encephalitis, the best that
physicians can do is try to treat the symptoms and problems associated with
brain swelling, deal with associated complications where treatable (e.g.
bacterial pneumonia), and hope for the best.
No human vaccines yet exist for WNV or EEE, although several efforts are
now underway to develop a vaccine for WNV.
Fortunately, transmission of EEE to
humans is naturally a relatively rare event, and
modern mosquito control programs along the East Coast work hard to make such
events even rarer. A major impetus for
the start of modern mosquito control programs in the Mid-Atlantic region was
the 1959 EEE outbreak in Cape May County, New Jersey that occurred around Labor
Day, leading to the deaths of over 20 victims and hospitalizations of over 100
people (along with some severe economic consequences for a tourism-based area
too). Even with a subsequent expansion
and increased effectiveness of mosquito control programs in the Mid-Atlantic,
localized EEE outbreaks have occurred since then, not only in New Jersey but
also in eastern Massachusetts, Rhode Island, upstate New York, southeastern
Virginia, and northeastern North Carolina. Fortunately, the numbers of human
cases in these EEE outbreaks were relatively low. The most recent documented human case of EEE
in Delaware occurred in the mid-1980's -- the Mosquito Control Section takes
considerable pride in our keeping things this way, such that EEE does not have
major impacts on Delawareans, with the chances of you contracting EEE
exceedingly small.
To date (start of the 2002
mosquito-breeding season), there have been no human cases of WNV in Delaware,
but since the introduction of WNV in the New York City area during the summer
of 1999 (causing 62 hospitalizations and 7 deaths at that time), the virus has
spread and proliferated throughout the Northeast, and has rapidly moved south
to Florida and Louisiana and west to Wisconsin and Illinois. Within our region during the summer and fall
of 2001, there were 12 human cases of WNV in
Additional information about the
human health problems/symptoms of WNV, or concerns for its possible
contraction, can be obtained by calling the Division of Public Health (Epidemiology
Branch) at its office in
11) There
are a lot of biting flies around here that I don’t like (or gnats, or ticks, or
wasps, etc.). Can’t Mosquito Control do
something to get rid of them?
While the Mosquito Control Section frequently receives calls for help not related to mosquito problems, unfortunately the answer here is NO (even if you get mad at us). By our enabling State statute, for pest management purposes we are charged with and only allowed to take actions that control mosquitoes. Given the varied and vast amounts of mosquito-breeding habitats in Delaware and the long flight ranges of some mosquito species, plus the State’s high human population density, coupled with the intolerable quality-of-life and human health threats that severe mosquito infestations can cause, our just battling mosquitoes gives us plenty to do – trying to attend to any other pest problems would be beyond our capabilities in terms of time, staffing, budget or other resources, and legally not in our authority to do anyhow. But this doesn’t mean that we still can’t provide you some advice or guidance, which we do below.
There are many species of biting flies in Delaware – greenhead flies in or near saltmarshes; deer flies where forested edges or shrubby areas abut marshes or open fields, especially along the coast; horse or stable flies around farms; and shore flies that can be quite annoying ankle-level biters along our beaches. Biting gnats (punkies or no-see-ums) at times can be very annoying, especially in late spring and early summer along tidal wetland margins or near other watery/muddy areas. In recent years the public has become much more aware of tick-borne problems because of the emergence and widespread nature in Delaware of Lyme disease, spread by the very small deer tick, which can also transmit human granulocytic ehrlichiosis (HGE); other tick-borne concerns in Delaware are associated with the wood or dog tick, as a carrier of Rocky Mountain spotted fever, and the lone star tick, capable of transmitting human monocytic ehrlichiosis (HME). Calls will also come to us for what to do about problems with bees, hornets, wasps, yellow jackets, velvet ants, etc., which can be a special concern to those individuals susceptible to anaphylactic shock from their stings. We’ll occasionally get questions about chiggers (“red bugs”), or if the spider that somebody saw in their storage shed was a black widow. We’ve also taken queries as far afield as gypsy moth spraying, or dealing with concerns about rabies transmission. Even calls about bats in the attic, skunks under the porch, snakes in the crawlspace, beavers flooding the driveway, or moles in the lawn have come our way. Without spending an inordinate amount of time trying to explain to the public that we’re not the agency or personnel to call about such problems or issues, we still courteously and patiently try to point these often distraught callers in the right direction, concerning both what we can and can’t do, and who they might want to contact next.
We recommend that for many
non-mosquito pest problems a first point-of-contact be the University of Delaware Cooperative Extension
Service, with the Extension Service having offices in all 3 counties. Expert agents in the Cooperative Extension
Service can give you advice about how to handle that wasp or hornet problem, or
how to lessen biting fly problems (e.g. they can give you a handout showing you
how to construct a fly box trap for reducing greenhead fly populations adjacent
to saltmarshes). If you bring in the
tick that you found crawling in your bed or that you pulled off your leg, or a
specimen of any other type of unknown insect, spider, or invertebrate critter
of interest that you might have in-hand, they can usually have it identified
for you. The Extension Service is also
the obvious place to call for questions about garden or ornamental plant pests,
as well as agricultural crop pests. The
Extension Service phone number to call in
For additional questions related to agricultural,
forest or ornamental plant pests, including concerns about gypsy moths, one can
call the Delaware Department of
Agriculture offices in
12) Describe
the Mosquito Control Section. How many
people work for you? Who are you
folks? Where do you work? What do you do in the winter? Who do you work with? Who are your partners? What’s your budget?
The Mosquito Control Section is
part of DNREC’s Division of Fish and
Wildlife, and has a staff of 19
people working full-time year-around
to deal with
Aerial spraying of insecticides, whether done by fixed-wing aircraft or helicopter, is all contractually performed by private professional aerial applicators, who throughout our control season are available on short-term standby basis to meet our spraying needs. When and where to perform aerial spraying and what products/rates to use are solely the calls of our Mosquito Control staff, and as such we do each spraying’s technical planning and follow-up for quality control checks, as well as provide general oversight throughout each spray operation. While these private aerial applicators are not actually part of our Section staff, by the nature of what we must do, we have very close working relationships and interactions with our contractors at all times. All truck-mounted spraying (ground “fogging”) is directly performed by Mosquito Control staff.
The
Section has three facilities from which we conduct our statewide program. There is an administrative office in
Mosquito Control Section personnel have statewide responsibilities for controlling mosquitoes wherever they present problems to people, in urban, suburban or rural settings. Our staff work up-and-down the state from Wilmington to Odessa to Smyrna to Dover to Milford to Georgetown to Selbyville; and across-the-state from New Castle to Hockessin, Delaware City to Newark, Port Penn to Middletown, Kitts Hummock to Hartly, Bowers Beach to Felton, Slaughter Beach to Harrington, Lewes to Greenwood, Rehoboth Beach to Bridgeville, Bethany Beach to Seaford, and Fenwick Island to Laurel. Because of the millions of summer vacationers, visitors and tourists coming to Delaware’s beach resort communities, coupled with lots of nearby prime saltmarsh breeding habitats, the coastal strip from Lewes to Fenwick Island and areas around the Inland Bays are given special attention, but this doesn’t come at undue expense for meeting the statewide control needs of our many other constituents too. Special attention is also given to mosquito control on Delaware’s two National Wildlife Refuges, with mosquitoes produced from Bombay Hook National Wildlife Refuge capable of causing problems for people all along the eastern side of the Greater Dover-Smyrna area; and mosquitoes produced from Prime Hook National Wildlife Refuge capable of doing the same for people in the Milford-Milton-Lewes area, including the bayfront communities from Slaughter Beach to Broadkill Beach. [Indeed, it is only by our having excellent working relationships and cooperation with the U.S. Fish and Wildlife Service that the Section is able control Refuge-produced mosquitoes while the skeeters are still on-Refuge (at least for the most part), much to the relief of residents and visitors up to several miles away from a Refuge’s borders.] Overall, our “Mosquito Control District” encompasses about 2000 square miles, providing control services to about 800,000 residents and millions of summer visitors.
While the Mosquito Control Section’s active field surveillance/monitoring and insecticide treatment programs last for about 8 months, from around mid-March into mid-November, the Section continues to work hard year-around doing a variety of tasks. For example, source reduction work, such as Open Marsh Water Management (OMWM) and coastal impoundment management in particular (as described in FAQ #4 above), occurs all year long, weather permitting. Wetland habitat restoration or enhancement projects, often done in collaboration with our colleagues in the Division’s Wildlife or Fisheries Sections, also occur throughout the year. The 4 “winter months” from mid-November through mid-March are also the time of year when the Section is able to accomplish a lot of tasks that we simply don’t have the luxury to get done during the “heat” of our annual “skeeter wars” – e.g. this is time of year for short-term and long-term strategic planning, implementing facilities improvements or upgrades, taking inventories, making major machinery repairs, doing routine maintenance to insecticide spray gear or scientific equipment, performing research analyses, writing reports, tending to personnel matters, preparing permit applications, drafting contracts, attending scientific/technical meetings, making budget projections, etc. We often find that our spring woodland-pool control program, which kicks-off in mid-March, is all too soon upon us once again. There truly is no “downtime” for us throughout the year.
In carrying out our mosquito control activities, the Mosquito Control Section often comes in contact with, or has the opportunity to work with, many other programs within the Delaware Department of Natural Resources and Environmental Control (DNREC), not just within our own Division of Fish and Wildlife (DFW), but within all the other DNREC Divisions too. For instance, the Mosquito Control Section is the lead DNREC agency for the Department’s “Northern Delaware Wetlands Rehabilitation Program” (NDWRP), in which the Department has undertaken a long-term commitment to try to restore over 10,000 acres of degraded, urbanized coastal wetlands at over 30 sites along the lower Christina-Delaware River corridor. We are close partners with our Division’s Wildlife Section in undertaking Phragmites control projects, and with our Wildlife and Fisheries Sections for coastal impoundment management. In going about our day-to-day business, we also routinely interact with our Division’s Natural Heritage Program and our Non-Game and Endangered Species Program, to help ensure that our control activities do not adversely impact species or habitats of special concern, and wherever possible in our marsh management work that steps are taken to protect or enhance biodiversity. In undertaking our wetlands management work, we interact with DNREC’s Division of Air and Waste Management (DAWM) for marsh restoration projects in association with the Department’s undertaking Superfund site restoration projects, to help the DAWM achieve resource compensation for third party-caused natural resource injuries. We also interact with the DAWM in regard to trying to regulate or better control problems that are caused by scrap tire piles -- their providing prolific mosquito-breeding habitat is but one of several problems. We interact with DNREC’s Division of Soil and Water Conservation (DSWC) regarding the design and management of stormwater management basins, to try to lessen mosquito production problems while still retaining other good attributes of these desirable man-made features. We also interact with the DSWC’s Delaware Coastal Management Program and its Delaware National Estuarine Research Reserve about a variety of coastal zone policy issues and operational practices. Mosquito Control works closely with DNREC archaeologists in the Division of Parks and Recreation (DPR) to help ensure that our excavation activities don’t jeopardize historical or cultural resources, and that anything we might find actually adds to our knowledge of this resource base. The Mosquito Control Section also works closely with DNREC’s Division of Water Resources (DWR), Wetlands and Subaqueous Lands Section, in regard to wetlands permitting needs and a host of associated wetlands regulatory issues (including wetlands protection initiatives), and in regard to water quality concerns. For purposes of public information and education and media outreach, we work closely with DNREC’s Information and Education (I&E) office.
Besides interacting with our sister agencies within DNREC, we also have interactions with several other state agencies. For example, in regard to pesticide use and state regulatory issues, we interact with the Delaware Department of Agriculture’s Pesticide Compliance Section. To help avoid any problems with our spray operations affecting commercial beekeeping operations, the Mosquito Control Section has developed a set of procedures and protocols with the Delaware Department of Agriculture (State Apiarist) and the Delaware Beekeepers Association, designed to prevent or alleviate any problems. As part of the Mosquito Control Section’s virus surveillance/monitoring program, the Section contracts and works with the Delaware Division of Public Health Laboratory for analyses of our mosquito collections, sentinel chicken blood samples, and dead wild bird specimens that we collect and submit. To help the State get a better handle on dealing with West Nile Virus problems and issues, the Mosquito Control Section is an active partner in the State’s tri-Department “West Nile Virus Work Group,” which besides DNREC also involves the Department of Health and Social Services (Division of Public Health, Epidemiology Branch) and the Department of Agriculture (State Veterinarian). To help address concerns about any possible human health or environmental non-target impacts of our insecticide use, we work closely with the Division of Public Health’s Environmental Health Evaluation Branch. Concerns about potential impacts to historical or cultural resources in our undertaking OMWM or wetlands restoration work also cause us to interface with the Division of Historical and Cultural Affairs’ State Historic Preservation Office (SHPO).
On the federal side, in addition
to our interactions with the U.S. Fish
and Wildlife Service that we already mentioned above (regarding mosquito
control needs on our two National Wildlife Refuges), we also interact with the Army Corps of Engineers regarding
mosquito control problems occurring on the Corps’ dredge disposal sites. As
mentioned in FAQ #4 above, all of our Open Marsh Water Management (OMWM)
wetland alterations are done under regulatory oversight by the Delaware Mosquito Control Advisory
Committee (DMCAC), consisting of four federal agencies (Army Corps of Engineers, U.S. Environmental
Protection, U.S. Fish and Wildlife Service, National Marine Fisheries Service),
three DNREC agencies (Division of Fish
and Wildlife, Wetlands and Subaqueous Lands Section, Delaware Coastal
Management Program), and the State
Historic Preservation Office (SHPO).
The Mosquito Control Section is a very active participant in the American Mosquito Control Association (AMCA),
which is a scientific/management organization of over 1500 professionals from
hundreds of mosquito control programs around the country and world (from over
70 countries), academe, government, and industry. Through active participation in the AMCA, the
Section has the opportunity for input and influence regarding national or
regional issues with several federal agencies –
e.g. U.S. Environmental
Protection Agency, U.S. Fish and Wildlife Service, Department of Health and
Human Services (Centers for Disease Control), and Department of Agriculture.
In regard to legislative issues, our participation in the AMCA also
provides us with additional avenues of communication with Congress (primarily
through AMCA-coordinated actions with our two Senators, our Representative, and
their legislative aides). Besides
interacting at the national level via the AMCA, the Mosquito Control Section is
also a member program in the Mid-Atlantic
Mosquito Control Association (MAMCA), and we also interact with our
colleagues in the New Jersey Mosquito
Control Association (NJMCA). Our
professional staff are also members of other
scientific organizations such as the Society
for Vector Ecology, Estuarine
Research Federation, Society of
Wetland Scientists, and Ecological
Society of America.
In undertaking our control work, the Mosquito Control Section also has
considerable interactions with the private
sector, in that indeed this is our primary constituency (i.e. the
public). Our Open Marsh Water
Management (OMWM) projects are undertaken only after first having the
permission and cooperation from the private landowners who own much of
Depending upon available funding, the Mosquito Control Section also helps to plan, coordinate and participate in applied mosquito biology or mosquito control research projects with faculty or research associates of the University of Delaware’s Department of Entomology and Applied Ecology. We also interact with faculty or research associates of the University of Delaware’s College of Marine Studies for conducting applied research regarding wetlands ecology or management.
The Mosquito Control Section operates on an annual General Fund budget of about $1.7 million dollars per year, which includes a recent annual supplement of $150,000 per year to help us contend with increasing spray demands and to better address West Nile Virus (WNV) problems; and for the past 3 years we have also received about $100,000 per year in federal funds from the Centers for Disease Control, to help with WNV surveillance/monitoring, laboratory testing, and applied research. In comparison to mosquito control programs in many other areas around the country, whether the comparison is done on a per capita basis or an areal basis, Delaware’s statewide control program is one of the least expensive, and as such is apparently done quite frugally -- we feel that our approach delivers a very good return-on-investment for our citizens, being accomplished in very effective and environmentally-compatible manner.
If you
have further questions about the Mosquito Control Section, please call our administrative headquarters in