By Laura Jesse, ISU Plant and Insect Diagnostic Clinic
Flooding per se, does not lead to mosquitoes. It is the water that stands AFTER the flooding that creates opportunities for mosquitoes to breed. Heavy, frequent rainfall may lower mosquito population numbers because there is no standing, stagnant water in which the larvae can feed on grow (mosquito larvae do not live in running water).
It takes 7 to 10 days of standing water for the mosquitoes to develop, which is why we recommend to homeowners that they "flush" the bird bath at least once per week. We expect that with these drier conditions, the mosquito problem may increase in many areas across Iowa over the next few weeks.
Protecting yourself with a repellants containing DEET is the best option if you have to be outside during peak mosquito activity hours. Usually dusk, although mosquitoes can be active all day. Female Aedes vexans, a floodwater mosquito, usually rest during the day and seek out blood meals at dusk. This species can become prevalent after flooding, but is a species that has minimal involvement in the transmission of West Nile Virus.
Ken Holsccher, ISU Extension entomologist, wrote a more details article about mosquito management in the June 18, 2004 issue of the ISU Extension Horticulture and Home Pest News.
Laura Jesse is an entomologist with the Iowa State University Extension Plant and Insect Diagnostic Clinic.
The article was originally published in the June 16, 2008 issue of the ISU Horticulture and Home Pest News.