While you're sleeping, mosquitoes are making babies. Every third night each adult female lays 100 to 300 eggs on the surface of any standing water. It's an astounding reproductive rate that makes every gardener's job clear: wherever possible, make it hard for them to find still, standing water. Here are some useful strategies:
- Get rid of all unnecessary water collectors in the landscape such as empty plastic containers, old tires, etc., and fill tire depressions in the driveway. Park wheelbarrows upside down. Clean gutters. Fill tree stump holes with sand. Control irrigation so that water doesn't stand for more than a few days. Empty, clean and refill birdbaths every three to four days.
- For container water gardens or ponds, add Bti (the israelensis strain of the naturally occurring bacteria Bacillus thuringiensis) to control mosquito larvae. (This strain also works against fly larvae, too.) You can find Bti in most large garden centers, sold as "Mosquito Dunks" or "Mosquito Bits."
- Aerate ponds and stock with mosquito-eating fish such as Gambusia affinis ("mosquito fish"), minnows and goldfish. Keep your lawn mowed regularly and fencerows trimmed; tall grass and weeds are great daytime hiding places for adult mosquitoes.