NUISANCE MOSQUITO CONTROL

Nuisance mosquito numbers remain low averaging below our annoyance threshold numbers in our New Jersey light traps. Floodwater mosquitoes are likely to increase after the 4^th of July holiday due to rains June 26^th-28^th. Numbers will be moderated due to the previous dry conditions recovering from the drought of 2005. However, biting mosquitoes are expected to be more noticeable!

Crews continue to treat floodwater areas with Bti and methoprene.

CULEX MOSQUITOES

Culex mosquito numbers continue to increase due to the warmer temperatures. Elevated temperatures accelerate Culex development in stagnant water areas as well as the risk for WNV. Residents are strongly advised to inspect & eliminate all stagnant water areas from their properties that may produce these mosquitoes every week through the months of July-September. Any container that holds water and organic debris for greater than 10 days can produce many of these mosquitoes.

Stagnant water mosquito producing sites (detention/retention ponds, ditches, building foundations & container sources) will be treated with the microbial insecticide Bacillus sphaericus and the insect growth regulator methoprene.

MOSQUITO VIRUS SURVEILLANCE IN ILLINOIS

NWMAD has tested (VecTest) 355 batches of mosquitoes for West Nile Virus, St. Louis and Eastern Equine encephalitis. Twelve infected batches of mosquitoes were collected 1-Elk Grove Village, 1-Schaumburg, 1-Buffalo Grove, 2-Bartlett, 3-Wheeling 1-Des Plaines, 1-Palatine, 1-Rolling Meadows, 1-Arlington Heights gravid traps were positive for WNV via the District’s VecTest assay. Samples will be shipped out for confirmatory testing by Illinois Natural History RT-PCR testing and additional Culex collections and testing follow-ups will be performed.

As of this writing, the Illinois Department of Public Health (IDPH) reports: 20 counties with mosquitoes or birds testing positive for WNV. There are 34 WNV positive mosquito samples reported from Illinois (http://www.idph.state.il.us/envhealth/wnvsurveillance06.htm). Mosquito batches testing positive in the District are posted at the NWMAD website http://www.nwmadil.com/VECTEST1.htm.

Director’s note:

Numbers of infected mosquitoes at this point in time are similar to what we observed during the 2005 drought year in northwest Cook County, however, recent rainfall amounts now resemble 2002 precipitation levels. Relatively small rainfall amounts are not likely to wash out Culex mosquito larvae from typical ground surface stagnant water sites but significant rainfalls will flush out them & underground storm sewer systems. It is possible that weekly, minor rains will prevent evaporation of ground surface stagnant water sites and result in increased Culex numbers this year due to additional stagnant water habitats created. Currently, temperatures have been cooler than what was experienced during 2002 & 2005. As you may recall significantly cooler temperatures in 2003 & 2004 resulted in fewer human WNV cases. Warmer temperatures are required to accelerate mosquito development, biting activity, viral activity and numbers of Culex pipiens considered to be the primary human vector of West Nile virus.

ADULTICIDING (Night Spraying Operation):

Due to the detection of WNV infected Culex mosquitoes we are likely begin our night time adulticiding program weather permitting. Areas to be sprayed will include portions District territory where infected mosquitoes were collected and where higher densities of Culex were sampled.

Nightly spraying schedules can be viewed at the following website: http://www.nwmadil.com/nitespry_map.html. Alternately, a recorded phone message describing our scheduled nighttime spray program can be reached at (847) 537-2306 and pressing “5” on your telephone keypad. More information regarding our Adulticiding program may be viewed at: http://www.nwmadil.com/Night Spray info1.html

REDUCING THE RISK OF MOSQUITO BITES:

Avoid outdoor activity if possible from dusk to dawn when the mosquitoes bite the most. If you do go out wear light colored protective clothing and insect repellent (always read label warnings and directions). Make sure mosquitoes do not enter homes through unscreened or broken doors or windows. Residents are encouraged not to create mosquito harborage areas. Make sure tall grassy areas are trimmed and other vegetation is cut back. If plants must be watered do so in the morning so the vegetation and soil has a chance to dry making it less attractive to mosquitoes. Empty any containers holding stagnating water like tire casings, birdbaths, flower pots and barrels that may produce mosquitoes. Un-maintained swimming pools may produce thousands of mosquitoes. Call the District to report stagnant water areas that remain wet for more than 7 days. Additional mosquito avoidance/control practices may be found at the District’s website: www.nwmadil.com.

Mike Szyska

Director

PLEASE FORWARD THIS INFORMATION TO APPROPRIATE DEPARTMENTS AND AGENCIES.