NUISANCE MOSQUITO CONTROL

Nearly 5 inches of additional rainfall throughout the District Aug. 19-25th brings the monthly Aug. total to nearly 9.5 inches of rain. The 19-25th rainfall will produce another emergence of nuisance floodwater mosquitoes around the Labor Day weekend. These rains continue to create more floodwater production areas.

Crews are continuing to treat water areas with methoprene pellets which should provide protection till the end of the mosquito season. See Adulticiding control below.

DIRECTOR’S NOTE: Biting floodwater mosquitoes that that are very annoying will likely alarm the public as human WNV infections are also concurrently reported by health officials. Since it is unlikely that the residents of the District will be able to identify what mosquito species is actually biting them it would still be most prudent to encourage mosquito avoidance, control and self-protection to reduce the risk of infections. Please see NWMAD mosquito protection advice at: http://www.nwmadil.com/protecting yourself.htm.

CULEX MOSQUITOES

Culex mosquito numbers collected from gravid traps continue to be trapped at below average numbers than normally expected at this time of the season. It is likely that their numbers will increase if the warmer temperatures continue to prevail and as aging floodwater areas start to stagnate. 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 7 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 insect growth regulator methoprene (Altosid). Treatment of stagnating floodwater areas has been an intensive process given all the water out there. See adulticiding control below.

MOSQUITO VIRUS SURVEILLANCE IN ILLINOIS

The Illinois Department of Public Health (IDPH) reports: 25 counties with humans, mosquitoes or birds testing positive for WNV. There are 14 human cases (4-Suburban Cook County, 3-Chicago) of WNV and 655 WNV positive mosquito samples reported from Illinois. Thus far IDPH has reported 25 birds infected with WNV.

NWMAD has tested (VecTest/PCR) 672 batches of mosquitoes for West Nile Virus, St. Louis and Western Equine encephalitis. 95 WNV infected batches of mosquitoes have been collected in NWMAD gravid traps to date. Mosquito batches testing positive in the District are posted at the NWMAD website http://www.nwmadil.com/VECTEST1.htm.

ADULTICIDING (Night Spraying Operation):

West Nile Virus

As of the beginning of August, NWMAD has prioritized its night time adulticiding spraying in areas where mosquitoes have tested positive for West Nile virus and Culex mosquito numbers are elevated as indicated by surveillance traps. Much of the WNV activity, as in previous years, has been concentrated in the townships of Wheeling, Maine, Northbrook and Elk Grove. WNV activity currently has been reduced in the Culex mosquitoes as indicated by surveillance traps and virus testing of mosquitoes. This does not mean that virus activity and the possibility of human infections are completely absent in the District; just that the risk is lower than in previous WNV years at this same point in time. If above average temperatures return in September and flood area waters start to stagnate and produce more Culex mosquitoes the WNV risk could start to increase again.

Nuisance Floodwater Mosquitoes

The arrival of nuisance floodwater mosquitoes (Aedes vexans) due to rains beginning on the 5^th of August and subsequent record rains (for the rest August) has continued to exasperate this problem. Consequently, as of 8/21, NWMAD also began spraying for nuisance mosquitoes in the townships of Barrington, Hanover, Palatine and Schaumburg, as well as, the previously mentioned townships sprayed for WNV (the spraying will kill both types of mosquitoes). This adulticiding will likely continue until the problem is resolved.

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, tarp covers, 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.