Wetlands and Mosquitoes

Concerns about mosquito problems are often raised in relation to wetlands, especially due to the West Nile virus issue the past few years. However, contrary to popular belief, healthy, well-functioning wetlands can actually reduce mosquito populations. One common “belief” is that wetlands should be drained to control mosquitoes. However, mosquitoes have a very short life cycle (from four days to a month), and their eggs can remain dormant for more than a year, hatching when areas are flooded with water. Therefore, even if a wetland has been drained, it may still hold enough water after a rain to breed mosquitoes. An artificially drained area may actually produce more mosquitoes than it did when it was a natural wetland.

Healthy wetlands provide habitat for many insects and animals including natural enemies of mosquitoes. The predators keep the mosquito population low. Mosquitoes can become a problem, however, in areas that have standing water that do not support the beneficial predators that feed on mosquitoes, (such as old tires, birdbaths, and other containers that collect rainwater). Even hollow logs hold water and low spots in the ground can provide spots for water pools. And because these types of places do not provide good homes for beneficial insects and other kinds of wildlife that feed on mosquitoes, the mosquitoes can quickly reproduce.

The U.S. EPA and Indiana Departments of Natural Resources provide more information at http://www.in.gov/dnr/fishwild/publications/inwetcon/hlywet.pdf. Further information can also be found at the U of I Extension website www.urbanext.uiuc.edu/westnile/about.html.

June/July 2004: Prevent Garlic Mustard from Setting Seeds | Gypsy Moth: Know the Facts | Wetlands and Mosquitoes | Understanding Herbicides | Choosing Home Lawn Care Services