NUISANCE MOSQUITO CONTROL

Drier weather has reduced nuisance mosquito numbers over the last couple of weeks. Present populations of these mosquitoes may still annoy residents living around wooded areas when temperatures spike in the mid to upper 80’s or above.

CULEX MOSQUITOES

Culex mosquito numbers are again increasing as dry warm conditions favor the production of stagnant water that the larvae of these mosquitoes prefer. As is typical with increased numbers of Culex mosquitoes this time of the season the risk of West Nile virus infection to humans also increases. 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, catch basins, & other container sources) will be treated with the insect growth regulator methoprene (Altosid).

MOSQUITO VIRUS SURVEILLANCE IN ILLINOIS

The Illinois Department of Public Health (IDPH) reports: 15 counties with humans, mosquitoes or birds testing positive for WNV. There are 4 human cases (1-Cook:Skokie, 1-Kane, 1-Montgomery, 1-Macon County) of WNV (none in NWMAD territory) and 200 WNV positive mosquito samples reported from Illinois. Thus far IDPH has only reported 8 birds infected with WNV.

NWMAD has tested (RAMP) 557batches of mosquitoes for West Nile Virus. 40 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.

DIRECTOR’S NOTE: WNV infected mosquito abundance in Illinois is less extensive in 2008, thus far, as in previous WNV years with above average rainfall and cooler temperatures! Virus replication and mosquito activity slows down in cold-blooded mosquitoes during cooler temperatures and frequent significant rainfall tends to flush-out typical Culex stagnant storm water habitats prevalent in urban areas. This has lead to delayed WNV activity in NE Illinois. However, recent warmer temperatures and drier conditions the last couple of weeks are now again increasing WNV activity. It is possible if these warm & dry conditions continue (Aug-September), as they did in 2003, we could see increased infected mosquitoes and human infections. In such case, Culex mosquitoes would continue to be a threat until they stop blood feeding via diapause in preparation for hibernation. Currently the NOAA weather center is now predicting normal temperatures and precipitation for the month of September. If this prediction holds true then WNV infected mosquitoes will typically resolve by about the 1^st half of September.

ADULTICIDING (Night Spraying Operation):

NWMAD is now targeting WNV infected Culex as an adulticiding priority. Continuation of adulticiding is likely if virus activity continues to be demonstrated in the mosquito population and weather conditions are favorable.

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.