With flooding, there’s potential for ‘historic levels’ of mosquitoes

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By Alma Gaul | Friday, June 27, 2008 3:23 PM CDT | () comments

Just last week, Ken Holscher got a call from someone wondering whether you can spray your yard with Listerine to kill mosquitoes.

As an entomology professor at Iowa State University in Ames, Holscher hears lots of offbeat home remedies for bugs, but that was a new one.

As floodwaters subside throughout the Midwest, soggy conditions have set the stage for a possible explosion of mosquitoes, and anyone intending to spend time outside the next few months likely will be wondering what they can do to protect themselves.

Shop any home and garden, hardware or big box store and you’ll find lots of products claiming to be the answer: citronella candles, chemical sprays and various devices such as the Mosquito Magnet, which says it works by attracting mosquitoes and then trapping them.

Holscher’s opinion on many of these products is “buyer beware.” Although you can read glowing testimonials on the Internet, scientific-based research to back up the claims often is lacking, he says.

Still, we aren’t defenseless. Holscher offers the following top four recommendations:

1. Protect yourself with a spray containing the chemical compound DEET, the most effective Environmental Protection Agency-registered repellent. A concentration of 25 percent active ingredient is sufficient for adults. The higher the concentration, the longer the protection is expected to last.

Two other ingredients have been recommended by the Centers for Disease Control and Prevention as repellents: Picaridin (found in Cutter Advanced and Avon Skin So Soft Bug Guard, for example) and oil of lemon eucalyptus (found in Repel by Cutter and OFF! Botanicals, for example).

Holscher wouldn’t recommend any of these repellents for babies or toddlers, though; it’s best to just keep them out of the mosquitoes’ way or cover them up so they won’t get bit.

2. Protect yourself by wearing loose-fitting, long-sleeve shirts and long pants. Loose-fitting is important because mosquitoes can bite through tight-fitting fabrics.

Holscher understands that some people don’t like body sprays or cover-up clothes, but that is the trade-off, he says.

Also, try to avoid going out at dusk and dawn, when mosquitoes are most active.

3. If you are hosting a big outdoor party in which you feel you absolutely must do something for your guests, then a day or two in advance of the event, spray your yard — shrubs, grass and low-hanging tree limbs — with a product containing a pyrethroid. This is a manmade chemical similar to pyrethrum, a natural insecticide found in chrysanthemum flowers.

Brand names include Tempo, Bug Be Gone and Home Defense.

You also can hope for a breezy day (or evening), and you can stock a supply of bug spray, towelettes or lotions to offer your guests.

4. Get rid of standing water on your property. Don’t leave water in your child’s plastic pool for more than a day, refresh your birdbaths and check to make certain you don’t have water sitting in your flower pots or rain gutters.

If there are areas of your yard where you can’t eliminate water — a chronically wet area or a pond without fish — you can treat the water with a larvicide such as Mosquito Bits or Mosquito Dunks that contains the naturally occurring Bacillus bacteria. It is considered nontoxic to humans, wildlife and pets, and it can be put in birdbaths and plant saucers.

As for whether there will be a bumper crop of mosquitoes this year, it all depends on the summer weather, Holscher says. If the ground that is flooded re-floods, there will be more mosquitoes. If the ground that is flooded dries out and stays dry, mosquito populations will be within normal ranges, he adds.

“Rainfall patterns from here on out” will determine the severity, he explains.

Mosquitoes “may not get as bad as people are thinking,” he says. On the other hand, “the potential is there” for historic levels, he adds.

Alma Gaul can be contacted at (563) 383-2324 or agaul@qctimes.com.

What’s your secret?

Do you have a favorite remedy for mosquitoes and gnats?

E-mail your ideas to agaul@qctimes.com; put “secret” in the subject line.