Don't raise mosquitoes in your yard!

Dave Robson

This year may be classified as the Year of the Mosquito. Or it might not be.

It's hard to predict insect populations year to year. Spring populations are easy to get a handle on due to winter conditions, but spring conditions have an effect on summer populations, summer weather affects fall insects, and so forth. You really can't predict problems for more than one season in a row.

However, warm winter conditions and plenty of spring rains mean mosquito populations may be heavy this summer. Breeding areas are numerous and larvae soon will be hatching.

Mosquito problems in your yard can be reduced by eliminating breeding sites. This is key to any type of mosquito control program. Fortunately, an ongoing program of eliminating these sites in your yard is easy and not very time consuming. However, it must be done regularly.

Mosquito outbreaks, in which large numbers of biting mosquitoes are present for several days, are the result of lowland flooding a couple weeks previously. Eggs laid in these low areas can be dry for months.

Heavy rains flooding these areas cause eggs to hatch, resulting in larvae that develop into adult, biting mosquitoes in about two weeks. If you have areas of your property flood for at least 10-14 days at a time, adjust drainage so areas drain better or maintain it as a permanent pond to allow you to reduce mosquitoes from these areas.

Permanent bodies of water, such as ponds, abandoned swimming pools, and garden pools should contain top-feeding fish to eat any mosquito larvae that try to develop. Gambusia, known as mosquito fish, most bait minnows, or guppies in water bodies will eliminate any mosquito larvae present.

If the water is shallow, the fish may die from heat or freezing and have to be replaced occasionally.

When selecting fish, realize Gambusia may be difficult to find since they do not overwinter here, guppies need water at least 60 degrees F. or warmer, and goldfish may not eat enough mosquito larvae to be effective. Minnows from a bait shop probably be the cheapest, most available form of season-long mosquito control.

Mosquitoes can also be controlled as larvae in water with insecticides. Bacillus thuringiensis israeliensis, a bacterium that kills only the larvae of mosquitoes and closely related insects, is available in some garden centers.

Other mosquitoes will develop throughout the summer in small amounts of water that may accumulate in birdbaths, old tires, tin cans, and other containers lying around the farm. It is essential these areas be managed properly. Removing them is the best.

If you can, get rid of these containers, pierce them so they do not hold water, or empty and dry them at least once a week so mosquitoes are not able to develop in them.

David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, Cooperative Extension Service, University of Illinois. You can write to Robson in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: (217) 782-6515. E-Mail: robsond@idea.ag.uiuc.edu

16 ILLINOIS COUNTRY LIVING JUNE 1998