Frequently asked questions
can't I see any spray or hear any noise coming from the spraying truck
when it drives by my home?
The machines used in
spraying are much quieter than they once were. They are also designed
to put out insecticide droplets that are an average of 17 microns in
size. The droplets are small so that they can drift further. Once the
droplets are a few feet from the truck, they spread out and can no
longer be seen.
didn't your crews bring the spraying truck down my street tonight?
Several factors decide
the route our trucks take. Spray directions are first based on wind
readings taken every hour. For example, if there is a south wind, the
trucks will drive along the avenues (instead of the streets) so that the wind could carry the
droplets into backyards. Another factor that is taken into account is
the products can not be sprayed within 100 ft. of creeks and rivers. We
may also have residents in the area that have requested we turn off the
spray within a certain distance from their homes.
Can I eat vegetables from my garden after mosquito spraying takes place?
We recommend that you wash
fruits and vegetables thoroughly before consuming them.
labels for the products used in our spraying state that they "can be
applied over specific growing crops and range grasses prior to harvest
for the control of adult mosquitoes and biting flies within or adjacent
to these areas." Labels and Material Safety Data Sheets are available at
was thinking of purchasing one of those mosquito trapping devices that
use carbon dioxide to attract mosquitoes in your yard. Do they really
These devices can
provide some degree of protection, but do not rely on them for total
control. Traps used along with source reduction and repellents
will provide more relief.
- What about
using bats, birds, plants, fish candles, or bug zappers to control the
general, these things will not provide consistent or effective control
of adult or larval mosquitoes. Birds and bats do consume mosquitoes,
but they are opportunists, meaning they eat many different things and
consume whatever is most abundant at the time. But both bats and birds
combined still don’t consume enough mosquitoes for you to notice a
difference in the mosquito population. Citronella plants have been
shown to be ineffective, and the candles are only slightly better (the
light from the flame can actually attract more mosquitoes than it
repels). Bug zappers are not effective in reducing mosquito
populations, and can kill great numbers of non-target insects such as
don't you spray when the weather is cool?
used by Cass County Vector Control must be applied when the temperature
is at least 55 degrees and the wind is less than 10 miles per hour. This
product thickens when the temperature is below 55 degrees.
The mosquito count also plays a role in Cass County's decision of when
to apply spray.
- Can my dog and cat get West Nile Virus?
Yes, these animals can get the virus if they are bitten by an
infected mosquito. It is likely that they will make a full recovery if
infected. No specific treatment is available, but veterinarians can
treat symptoms of the virus.
- Can my pet transmit the virus to humans?
There are no documented cases of animal-to-animal or animal-to-human
- Are the pesticides that Cass County sprays to kill mosquitoes
Permethrin and sumethrin are the main pesticides used for
mosquito control by “sprayer trucks” in
They have many other uses, too. For example, both are applied to the
human head to treat lice and are found in products applied to pets.
The U.S. Environmental Protection Agency (EPA) licensed
permethrin and sumethrin for use in mosquito control after evaluating
them for potential human health and environmental effects.
We feel the benefits of using these products outweigh the
limited risks they might pose. Because mosquitoes can transmit the
life-threatening West Nile Virus and other illnesses, it’s very
important that we control the mosquito population. Permethrin and
sumethrin are an effective way to do this.
To learn more about the EPA approval process for pesticides
and mosquito control, visit
What is "larviciding"?
A larvicide is an insecticide used to kill or prevent the growth of
mosquito larvae. We use a variety of larvicides in our program, varying
from granular form, pellet form and briquet form. The term larviciding
refers to applying these insecticides directly to mosquito breeding
Larviciding is an
effective method for controlling mosquitoes because the mosquitoes are
concentrated in a small area.
- How do officials decide when to spray for mosquitoes?
The Cass County
mosquito control program focuses first on controlling mosquitoes before
they mature into adults. This is accomplished by treating breeding
sites with larvicide. If additional control is necessary, the decision
to adulticide is based on analysis of adult mosquito populations,
weather conditions, and citizen requests.
- How can I distinguish mosquitoes from
other insects that look similar?
Visit this Colorado Web site for a great answer to this question.
- How long can mosquitoes live?
Male mosquitoes hatch first and usually live six or seven days.
Female mosquitoes may only live for two weeks in the summer, but with
enough food could survive for five months
- How long can mosquito eggs live?
can survive for up to five years.
After a female mosquito
has taken a blood meal she lays her eggs on or near open water. She can
lay 200-400 eggs at a time. When conditions are right, the eggs hatch
into larvae. This stage of development lasts 4 to 10 days depending on
water temperature, species, and food availability. The larvae then
morph into pupae, which is the final aquatic stage. From the pupal
stage, the adult emerges and rests on the surface of the water until
their wings dry and they become strong enough to fly away and feed.
What is West Nile Virus?