Mosquito Numbers Down: How Low Can They Go?

Below is the summary of mosquito activity in Iowa from the ISU Medical Entomology Laboratory. Mosquito surveillance in Iowa has been ongoing since 1969. During the summer months, the Iowa State University Medical Entomology Laboratory, in cooperation with the Iowa Department of Public Health and the University of Iowa Hygienic Lab, monitors mosquito populations and mosquito-borne diseases in Iowa.


The Iowa mosquito collection data for the year are available online at the Iowa Mosquito Surveillance website.  The statewide average mosquito counts by week (including a comparison to last year's mosquito activity) are shown.


Summary for the week of August 19, 2013


The Iowa Mosquito Net data show that statewide mosquito counts are as low as they've been since early June. If we had to give a mosquito forecast for the rest of the year we would predict that mosquitoes will remain in low abundance in the upcoming months, fluctuating slightly from week to week through September and coming to a close in October.


However, this is not definite. The mosquito species that we encounter most often (Aedes vexans, Ae. trivittatus, and Ae. sticticus) will try to squeeze in as many generations as possible as long as weather permits. This means that if temperatures remain as warm as they are right now and if we receive enough rainfall, we could see a late-season resurgence. Small amounts of precipitation will do very little to mosquito populations right now because the ground is dry enough that it will soak up whatever rain it receives, failing to result in the standing water that mosquitoes need to breed.


Although mosquito numbers are low across the board, the West Nile virus vector species do a great job at maintaining a baseline level of abundance throughout late summer and early fall.  Because we are in the midst of West Nile virus "season," these species (Culex pipiens and Culex tarsalis) can be more important than what their numbers indicate.


To that end, keep up your mosquito control practices. Reduce mosquito breeding by emptying containers of standing water, and keep mosquitoes at bay with insect repellent.


Mosquito trap catch data from the ISU Medical Entomology Laboratory, August 23, 2013.Mosquito trap catch data from the ISU Medical Entomology Laboratory, August 23, 2013.


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on August 23, 2013. The information contained within may not be the most current and accurate depending on when it is accessed.