Mosquitoes
Least-Toxic
Options
Step One. Is it a Problem?
--------------------------------------------------------------------------------------------
There are many hundreds of species of mosquitoes. Only
a few species bite humans, including some that can cause serious health issues
if they are infected with disease-causing organisms. Mosquitoes also provide a valuable food source for birds,
fish and other aquatic life.
Mosquitoes develop through
several life stages before reaching the flying and biting adult
stage. Younger, larval stages are aquatic - living in water.
Mosquito eggs can live for a long time, hatching quickly when wet.
Larvae can complete development in as little as 48 hours,
resulting in a large, biting adult population shortly after rain or
irrigation.
WARNING: Mosquitoes
can carry diseases with serious consequences, including encephalitis,
malaria and West Nile virus. Professional help in
dealing with persistent mosquito problems is highly recommended! Use the
information on the web page at your own risk.
Step Two. Inspection ---------------------------------------------------------------------------------------------------
Reducing mosquito problems depends on
keeping biting adults out of living spaces, eliminating water sources for
larvae where possible and treating those that cannot be eliminated.
Once in the adult stage, mosquitoes can fly for a mile or more - so good
management should be community wide. Enlist your neighbors in your
mosquito inspection and prevention program!
As you inspect, make a list of any issues
or sites that cannot be corrected immediately. Mark those on a
map. Create and implement a follow up plan as soon as possible.
- Carefully inspect door, window and vent
screens for holes and gaps between the screen frame and structure.
- Inspect buildings and grounds for
standing or slow-moving water sources where mosquito larvae may be
developing. In warm temperatures, moisture may only be required
for 2-3 days to allow mosquito adults to emerge, so the best time to
inspect may be immediately after a rain or irrigation.
Sites that can be corrected to prevent
breeding and development include:
- puddles on roofs, canopies, playgrounds,
parking lots, driveways, lawns, playing fields, etc.
- compacted, heavily trafficked sites on
lawns and playgrounds may suffer from very slow drainage, allow
mosquitoes time to develop into adults
- clogged or poorly aligned gutters and
downspouts
- damaged structural elements that may
create a pool for water to collect
- damaged trees with holes or depressions
that collect water
- buckets, tires, flower pots or other
objects that collect water
Sites that can be treated to prevent
breeding include:
- storm water catch basins
- bird baths
- fountains
- ponds
- pools alongside faster-moving streams or
rivers
If you look carefully, you may be able to
spot mosquito larvae which are active swimmers often at or near the water
surface. However, if larvae are not present, don't assume it's ok to
leave the water source in place or untreated. Eggs may not have
hatched yet, larvae may have already completed development, or the
population may just be very low at the time you are inspecting.
Step Three. Prevention --------------------------------------------------------------------------------------------------
1. Exclude mosquitoes from living areas
with well-maintained screens on
windows, vents and doors. Keep doors and windows closed when not in
use.
2. Reduce habitat for mosquito larvae
by removing, covering or adding
drainage holes to any objects outdoors that may collect rain or irrigation
water, including dumpsters and trash cans. Discard trash or debris
such as old tires, cans, etc. from school and neighboring
property.
Outdoor fountains, bird baths, tree holes, clogged gutters,
dripping or leaking water bubblers or faucets, irrigation ditches, catch
basins, ponds or other stagnant or slow-moving surface water should also
be managed to eliminate standing water (or see treatment options
below).
Slow draining soil, where water stands for
more than 48 hours after irrigation or rainfall, should be improved to
increase infiltration rates with aeration and/or soil amendments.
Step
Four. Least-Toxic,
Non-Chemical Options --------------------------------------------------------------
1.
Biological controls include fish
that feed on mosquito larvae. These can be added to fountains or
other contained outdoor water sources. Gambusia
species are generally a more effective option than goldfish or Koi.
Be sure to choose species native or already established in your
region.
2.
Traps include devices made for killing any insect attracted to the
trap, such as electrocuting light traps, and specialized devices
designed specifically to attract and kill mosquitoes. The
general attract and kill traps are not recommended - they are
typically ineffective in reducing mosquito populations and bites, and
kill many beneficial insects.
Specialized
mosquito traps often include light, heat and scent attractants.
Brand names include Mosquito MagnetTM,
Mosquito Mega-CatchTM,
Sonic WebTM,
and many others. As of yet, there is no solid evidence to
support the use of these types of traps to reduce mosquito populations
and bites in school settings. The traps do catch mosquitoes,
some more than others, but it is unclear if that translates into
mosquito nuisance and health risk reduction.
In
any event, trapping should never be used as a primary strategy to
manage mosquitoes.
Step 5. Least-Toxic Chemical Options
Larvacides
are pesticides applied to kill mosquito larvae. This strategy
reduces the amount of pesticide applied because it focuses on breeding
sites where larvae are concentrated - before they reach the winged, adult
stage and can disperse widely.
Adulticides are pesticides aimed at mature, winged mosquitoes. This
strategy is less effective in reducing breeding and reproduction, and is
more likely to have negative impacts on other beneficial insects and
organisms.
Repellants
NEED TO ADDRESS THESE IF ONLY TO SAY WE'RE NOT LOOKING AT THEM. XX
Use with Justification-------------------------------------------------------------------------------------------------------
All pesticides can be hazardous and
should be used as a last resort, only when non-chemical measures are not
effective. Use of the following pesticide products may be
justified when non-chemical measures are not adequate to resolve a
problem. These products contain ingredients which meet our criteria for least
toxic. Warning.
Note:
For detailed product information, click on the product
name to link to the Pesticide Action Network Database. This option is
available for EPA- registered pesticides only.
The
following larvacides are least-toxic pesticides that may be applied directly
to mosquito breeding sites, reducing the possibility that pets or people might come in contact
with the pesticide.
The
following repellants are least-toxic according to our criteria:
Click here
to see a list of pesticides for mosquitoes that do not meet
our criteria for least toxic.
