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    NWMAD provides mosquito control to 242 sq. miles of northwest Cook County in the townships of: Wheeling, Palatine, Barrington, Hanover, Schaumburg, Elk Grove, Northfield  (NW 6 sq. miles) and Maine.  Night spraying, when scheduled, will begin at sunset and conclude around midnight.  Neighborhoods initially targeted for night spraying will be those areas where West Nile Virus infected humans, horses, birds and/or mosquitoes have been detected and areas with high Culex mosquito numbers.  Currently, NWMAD uses the following criteria for spraying for WNV during the night-time hours:  WEST NILE VIRUS SPRAY CRITERIA

NWMAD uses a rapid diagnostic test called the RAMP  for the detection of West Nile Virus in mosquito batches.  The test indicates if virus is present in the mosquitoes, and because the results are immediate, it allows us to modify our mosquito control priorities as needed.   A mosquito batch is a collection of adult female mosquitoes of the Culex variety that are thought to be the primary group of mosquitoes capable of transmitting West Nile Virus.  Typically, these mosquitoes are produced in stagnant water areas (i.e. catch basins, containers, un-maintained swimming pools, flooded construction foundations, flower pots, tires, ditches, etc).  Culex mosquitoes, unlike typical common, nuisance floodwater mosquitoes, increase rapidly in numbers during dry, hot summers in the Midwest. The aquatic larvae of this mosquito exploit stagnant water areas, which are better protected from evaporation, than open water areas. 

NWMAD will also utilize its night spraying program in severe nuisance mosquito outbreaks.  Typically, these nuisance mosquito problems are caused by our most common floodwater mosquito Aedes vexans.  This mosquito is produced in enormous numbers after significant rainfall.  District information and criteria for spraying at night for this mosquito is:  NUISANCE MOSQUITO SPRAYING

Residents are strongly advised to inspect their property for standing water problems that may produce Culex mosquitoes.  Report any new stagnant water areas (those that retain water for longer than 7 days) to NWMAD by clicking on the following link:  Report Stagnant Water.  Alternately, you can call us at (847) 537 2306 and use the voice mail reporting system by dialing 3 on a touch tone phone.   NWMAD regularly inspects and treats, if necessary, over 6500 catalogued mosquito production water sites in our District during the mosquito season.  Additionally, hundreds of temporary ditches, low areas, tire piles, new building foundations, are also inspected and treated as needed.  Catch basins are treated regularly throughout the summer specifically for Culex mosquito control.  Residents are also advised to follow  Illinois Department of Public Health guidelines to reduce the risk of mosquito-borne diseases.

NOTE:  Mosquito nighttime spraying is sometimes mistakenly blamed for damaging plants (especially common evergreen or conifer varieties).   This is extremely unlikely given the small amount of insecticide used during our night spraying programs.  Typically, evergreen plants are reported as damaged (browning or dead).  Generally, this damage is always due to harsh winter weather conditions and/or deicing (salt) products used on many road ways and first noticed in the spring time. Salt can damage plants in two ways; by direct contact and if leached into the soil by killing roots and preventing water uptake.  Residents are advised to not use deicers near plants and also to be aware that fast moving roadway traffic frequently makes salt airborne transporting it considerable distances from roadways causing damage. Drought conditions may also kill or cause severe damage to many plants during exceptional hot/dry years (i.e. 2005, 2012).   Typically, tree damage from drought is first observed by the browning of the outer edges of leaves when water is not absorbed by the roots.  In severe drought years damaged or dead branches in larger trees is not uncommon especially when community water restrictions are in place.  If salt or drought damage to plants is presumed residents are advised to increase watering to rehydrate and/or flush salt from the soil.  This may have limitations in heavy clay soils.  In such cases; residents are advised to contact their local arborist for additional help.