The following is the summary of mosquito activity in Iowa from the ISU Medical Entomology Laboratory; August 19, 2011.
Statewide, mosquito activity in Iowa has continued to decrease and is as low as it has been all year. Aside from flooding in certain locations, rainfall has been quite low, and mosquito numbers have followed suit. CDC traps in Council Bluffs in recent weeks have yielded extraordinarily high numbers of mosquitoes right at the front of the floods. However, even in places like Council Bluffs, traps across town from the flooding have caught low numbers that cause no alarms. This stresses the importance of assessing mosquito activity on a local basis; that is, in specific environmental areas as opposed to on a city- or county-wide level.
Although it is too soon to state for certain (and we won't jinx it), 2011 may very well be concluded as a lame year for mosquitoes in Iowa. We can liken mosquito activity right now to that of late September in most years, so the relative drought has hastened the decline of mosquito populations by about a month despite temperatures that are high enough to sustain high mosquito activity.
Mosquito diversity is highest toward the end of the season, so we are seeing plenty of Anopheles, Psorophora, and Uranotaenia species along with the typical Aedes and Culex species.
We are in the period of West Nile virus activity. Blood from sampled chickens has tested positive for WNV in Des Moines, Council Bluffs, and Sioux City so far this year.
Visit the Iowa Mosquito Surveillance website http://mosquito.ent.iastate.edu/ to see the updated, mosquito collection data for the year. The statewide averages of mosquito counts by week (including a comparison to last year's mosquito activity) are shown. Notice the dramatic difference between this year and last, when significant flooding resulted in thousands of mosquitoes being collected in single traps. Click on "County" on the left side of the page to see individual county data. Click "Year" to see historical data comparing yearly mosquito population trends.