NORTHWEST MOSQUITO ABATEMENT DISTRICT

147 W. Hintz Rd.

Wheeling, IL. 60090

Phone: (847) 537-2306

Fax: (847) 537-2583

www.nwmadil.com

Mosquito Update

August 4, 2008

PRESENT CONTROL STATUS:

NUISANCE MOSQUITOES

Nuisance floodwater mosquitoes (Aedes vexans) are starting to increase again due to rainfall 7/18-7/20 throughout the District (1.3-2.2”). This rainfall is not likely to produce floodwater mosquitoes in numbers experienced late June- early July due to less rainfall and drier soil conditions. Rainfall throughout July was disproportionate with more mosquito-producing floodwater areas on the northern portion of the District. Although control efforts have greatly decreased nuisance mosquito numbers, as typically encountered with these mosquitoes, nuisance problem areas may persist in heavily wooded areas.

Crews are continuing to treat infested water areas for the developing mosquito larvae with methoprene Larvicidal oil’s & MMFG.

CULEX MOSQUITOES

Culex mosquitoes are still comparatively low compared to prior WNV years normally typical this time of the season as indicated by gravid traps. Warmer temperatures continue to slowly increase numbers of these mosquitoes.

Residents of the District are still advised to inspect their properties for stagnant water filled containers that may produce these types of mosquitoes. Examples of mosquito production areas encountered by homeowners can be viewed at: http://www.nwmadil.com/breeding sites1.htm.

Crews are currently treating stagnant ground surface water sources with methoprene pellets, MMFG & Bacillus sphericus. Catch basin treatments are completed and a second treatment in now beginning. Culex pipiens larvae have been prevalent in ditches culverts and other stagnant water areas after rainfalls and these are being treated at the same time as the nuisance mosquitoes after rainfalls.

ADULTICIDING (NIGHT SPRAYING):

Crews have completed 1 pass of adulticiding through the entire District and two to three times in problematic areas in the northern half of the District. Night spraying was performed on 6/25, 6/26, 7/1, 7/8, 7/15 and 7/30. Heavily forested areas continue to be problem areas especially in the northern & southwestern portions of the District where we are also getting floodwater mosquito migrations in from areas outside the District. Unlike Culex mosquitoes, that don’t migrate long distances, floodwater mosquitoes may travel several miles in a single evening making them difficult to control. If Culex mosquitoes and West Nile virus activity increases adulticiding activity will continue.

MOSQUITO VIRUS SURVEILLANCE IN ILLINOIS

Mosquito batches testing positive for these viruses in the NWMAD territory will be posted at the following website address: http://www.nwmadil.com/VECTEST2008.htm . Currently NWMAD has tested 406 batches of mosquitoes for West Nile virus (WNV) and 7 were positive with WNV. Positive batches were detected in Arlington Heights, Buffalo Grove, Prospect Heights, Hoffman Estates, Streamwood and Elk Grove Village.

Compared to prior WNV years mosquito infection rates are low for this time of the year. Control efforts, cooler temperatures in the spring and flushing rains contributed to this. Typically, Culex mosquitoes and WNV activity are suppressed during floodwater mosquito years. However, warmer temperatures and dry conditions, if they persist, can quickly advance virus infections in mosquito populations.

No human cases of WNV have been reported in the State of Illinois in 2008.

The Illinois Department of Public Health has reported that 65 batches of mosquitoes tested positive for West Nile virus (WNV) in Illinois; 47 from Cook County. More information about WNV can be found on the state’s website www.idph.state.il.us/envhealth/wnv.htm or by calling 217-782-5830. The State’s website also has other valuable resource links on WNV, pesticides and mosquito control.

NWMAD WEBSITE:

Report 10-day standing water problem: http://www.nwmadil.com/water source rpt.htm

Report sick/dead birds or other animals: http://www.nwmadil.com/Dead Birds.html

Check night time mosquito spraying schedules: http://www.nwmadil.com/nitespry_map.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, loose fitting, 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 unnecessary 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 for 5 days or longer like: tire casings, birdbaths, flowerpots and barrels that may produce mosquitoes. Make sure rain barrels or other storm water runoff cisterns are fitted properly when installed, well screened, free of detritus or organic material and mosquito-proof. Neglected swimming pools may produce thousands of mosquitoes. Call the District to report large stagnant water areas that remain wet for more than 7 days.

Mike Szyska

Director

PLEASE FORWARD THIS INFORMATION TO APPROPRIATE DEPARTMENTS AND AGENCIES.