A lot of people are worried about it and that's good. But it might be holding some people back from trying a water garden. To be honest, water gardens are going to be a healthier environment than flower pots filled with stagnant water or tires or crooked gutters or other things they may already have around the house. In a water garden, a pump is circulating the water so it's not stagnant. And if they have fish, fish will eat mosquito larvae.
What if someone has a small pond without fish?
The best thing we have is Mosquito Dunks (Summit Chemical, $8.97 for a six-pack). They're little doughnuts treated with Bt (Bacillus thuringiensis), a bacteria that kills mosquito larvae. They're organic so you can safely use them with fish or plants.
You just throw one in a small pond or anyplace you get stagnant water, like a gutter, which people often don't think about. Each Dunk treats 100 square feet. You can break them into pieces for small fountains or ponds. The package says they work for 30 days or more. You can also put them in rain barrels, animal watering troughs, unused swimming pools.
But you don't want to throw Dunks in when you're just starting a water garden. Remember, chlorine kills bacteria. It takes about 24 hours for chlorine to burn off, so wait a day at least before you put one in.
How about bird baths or other small containers?
Dump them and put in fresh water every day or every couple of days.
If you have a water feature with a pump, won't the circulating water eliminate the possibility of mosquito larvae?
Even if you have water circulating all the time, you're not 100 percent in the clear. Waterfalls can create moist areas under rocks and water can stand in areas next to the waterfall. Hose down the area around the waterfall every once in a while.
How long do you need to run the pump?
If you could, 24 hours a day. But some of these fountains and other water features are so shallow that, with evaporation on a hot day, you could burn out the pump. I'd say to run it for a while at least once a day. If you don't have fish or plants, you can add chlorine or bleach, which has chlorine in it. If you're going away on vacation, put in some chlorine or a piece of a Dunk.
Any other steps you should take?
If this is really going to bother you, if this is going to be on your mind all the time, don't get involved with water gardening. But if this is something you've always wanted to do, don't be afraid to live a little. Take some precautions and have fun with it. Don't let this mosquito win.
Correction/Clarification: (Published May 13, 2003) A question-and-answer column Saturday on water gardens and the West Nile virus failed to credit the source of the information. It came from Steve Katona, a water gardening expert at Home Depot in Ohio Township.
E-mail this story 
