Larvae & pupae of the floodwater mosquito (Aedes vexans) have been found, though, expected low nightly temperatures will prolong their developmental rate. Although this initial Ae. vexans brood was minimal due to the predominantly dry conditions through most of April; that has now changed. With an additional +2 inches of rain (more to come?) another larger brood will be on its way. Culex egg rafts have been observed in minimal numbers. Mean temperature for the month of April 2003 was 7.5 degrees cooler than April 2002. Additionally, April 2003 had more precipitation (+1.79 inches) than April 2002 in our District. In general, cooler temperatures and more precipitation favor higher production of floodwater mosquitoes (Aedes) over Culex. This, however, could change if temperatures increase significantly in May.

Crews have been treating off-road catch basins since the third week of April. This year we are performing catch basin treatments with a new 150-day residual methoprene (Altosid) insect growth regulator instead of the 30-day formulation used in the past. DIRECTOR’S NOTE: I wish to thank those cities/villages that responded to my October 2002 request to provide maps of off-road & backyard catch basins, subterranean vaults, pumping stations, flood control structures, tire pile locations and new building constructions! Your assistance will help our control efforts to further minimize the effects of West Nile Virus.

MOSQUITO VIRUS SURVEILLANCE IN ILLINOIS

Dr. Linn Haramis, Manager of the Illinois Department of Public Health (IDPH) Arbovirus Surveillance Program reports that the State’s dead bird surveillance program for West Nile Virus (WNV) will begin May 1^st. 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.

No mosquito batches have tested positive for WNV thus far in 2003. NWMAD will continue using the VecTest for detection of WNV and SLE in adult mosquito collections as it did in 2002. This year, however, we will be using an enhanced version of the VecTest that also provides for the detection of Eastern Equine encephalitis as well as West Nile and St. Louis encephalitis.

DEAD BIRD SURVEILLANCE:

NWMAD has received 3 dead bird reports. Since, the birds were not collected or severely decomposed and not submitted for testing it is not known what they died from. City and villages are encouraged to report dead birds to our District’s Dead Bird/Animal reporting web page which can be accessed at www.nwmadil.com. Knowing this information allows our District to better focus our control efforts (as it did in 2002). Enclosed with this newsletter is a memo provided by Dr. Linn Haramis (IDPH) for the shipping of dead crows or blue jays for virus testing in 2003. Please note that he states that anyone wishing to submit dead birds for testing should first contact your local health department for permission to submit it for testing. It is likely that IDPH will only test a limited number of birds as it did in 2002 to document the distribution of WNV. Also be aware of the proper precautions when handling bird carcasses as indicated in the memo.

NWMAD WEBSITE:

The NWMAD website (www.nwmadil.com) has been upgraded for easier use and will be adding additional information on homeowner mosquito control practices specifically addressing WNV control. The Mosquito Update newsletter is available at this site as well as information on the history of NWMAD, personnel contacts, mosquito information links, employment opportunities and spray schedules.

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. 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.