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Mosquito Control Ardsley, 8/2/17

Post Date:08/02/2017 9:35 AM

The Montgomery County Health Dept.(MCHD) is proposing  adult mosquito control within the highlighted areas of the attached map, due to West Nile Virus positive mosquito collections in the area.  The spraying will take place on Wednesday, August 2,  2017 with a Thursday, August 3,  rain date.  The application will begin at approx. 8:15PM and will end at approx. 10:30PM.  All spraying will be performed by MCHD personnel using a MCHD identified truck mounted ULV sprayer.  Individuals listed in the Pesticide Hypersensitivity Registry and Registered Apiaries within 500 feet of the spray area will be notified by MCHD. 

-Montgomery County Department of Health and Human Services


 Montgomery County Health Department (MCHD) Frequently Asked Questions regarding Mosquito Spraying

Why is my neighborhood being sprayed?
The Montgomery County Health Department conducts sprays in areas where WNV infected mosquitoes threaten human health. It is well documented that reducing populations of mosquitoes decreases the possibility of being bitten by an infected mosquito.

How does MCHD determine which areas are being sprayed?

If mosquito surveillance and testing show that there is a threat to human health, MCHD may initiate a spray to control adult mosquitoes. MCHD does not conduct nuisance mosquito control or take requests from the public for mosquito spraying.

How do I get my neighborhood tested?
The MCHD conducts adult mosquito surveillance throughout the county. However, we are always looking for additional areas to test. If you believe your neighborhood needs to be tested and would allow MCHD to conduct surveillance on your property, please contact the MCHD office closest to you.

Do the pesticides used during the spraying hurt people and pets?
MCHD conducts spraying carefully and follows all state and federal requirements. Most people and their pets do not have health effects during or after the spraying. Some people are more sensitive to the pesticides and are notified before the spraying occurs. If you have effects from the spraying, please contact your doctor.

Who is actually doing the spraying?
Spraying is conducted by certified MCHD personnel. On occasion, the Pennsylvania Department of Environmental Protection (DEP) will assist the MCHD with mosquito sprays.

Should I remain indoors during the spray?

It is the recommendation of the MCHD to stay indoors during a mosquito spray event and remain indoors for 15-20 minutes after the truck sprays your immediate area.

Should I close my windows and turn off air conditioner (a.c.) units?
MCHD recommends closing windows and turning off fans that bring outside air into your home. If your window or central a.c. unit can be switched to only recirculate and cool air within your home, it is safe to leave it on.

How far does the spray travel?
The spray can travel up to 300 feet from the source and still be effective on mosquitoes. Depending on the wind and air currents, spray residual could travel farther but not in concentrations that would be effective for mosquito control.

Should my pet remain indoors during a spray?

The mosquito control products used by the MCHD are considered safe for animals and pets when used properly. However, if you wish to limit your pet’s exposure, keep them indoors.

Should I take special precautions for my garden?
There is nothing you have to do to fruit or vegetable gardens. MCHD recommends washing your fruits and vegetables prior to cutting and/or consuming them.

Should I take special precautions for my swimming pool?
Your swimming pool and items in your yard should not be affected by mosquito spraying conducted at the proper label rates. Mosquito control products are applied at ultra-low volume (ULV) rates, generally below one ounce/acre, and rapidly break down in sunlight. However, some people choose to cover pools and other items as a precaution.

How are the pesticides applied?
All adult mosquito control events conducted in Montgomery County are performed with ultra-low volume (ULV) application equipment mounted on a truck, ATV or hand held. Residents can refer to press releases issued by the MCHD to find out what equipment is being used for a specific spray.

Why do you choose to spray at that time?
Mosquito sprays only kill mosquitoes that are actively flying during the spray event. We start at dusk, because research has shown that the mosquitoes involved in WNV transmission begin activity at dusk and are the most active for the next three hours.

How many species of mosquitoes are there?
There are currently 62 species of mosquitoes in Pennsylvania. Many of those can be found in Montgomery County. Thankfully, only a fraction of the mosquito species found in Montgomery County are a potential WNV threat. The MCHD targets those species that pose a risk of spreading WNV.

Will the spray kill all of the mosquitoes in my neighborhood?
Mosquito sprays will only reduce the population of mosquitoes in a given area. There are many factors that contribute to the success of any mosquito spray. Truck mounted sprays are limited by the vehicle’s ability to access all of the areas within a selected spray zone. Weather conditions, such as temperature and wind speed, will also affect how successful a mosquito spray will be. Only those mosquitoes actively flying during a spray event have the potential to be killed.

Are there any weather conditions that will postpone a spray?

Rain, winds under 1 MPH and over 10 mph. or temperatures below 55°F will each cause the postponement of a mosquito spray event.

Does MCHD notify residents in advance of mosquito spray events?
The MCHD notifies residents in several ways. A press release is issued for all adult mosquito sprays in Montgomery County at least 48 hours in advance. Individuals listed on the PA Department of Agriculture, Pesticide Hypersensitivity Registry and registered bee keepers within 500 feet of a spray area are personally notified prior to the event. Residents who would like to be notified of when spraying will occur should sign up for ReadyMontco. Press releases and maps of the control area can also be found on the MCHD website located at:
All local municipalities that are within a mosquito spray area are consulted and given detailed information about the spray.

How do I find out more information about the MCHD West Nile Virus (WNV) and mosquito control program?

More information regarding the MCHD West Nile Virus program can be found at:

Spray Area Map:

Mosquito Spraying Map

DUET Information downloadable PDF


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