Sunday, May 01, 2005

Are you breeding mosquitos?

We've had a lot of rain this year. And it seems that most people have watertight containers in their yards which have caught some rainwater -- often something along the side of the house or out in a neglected corner. Mosquitos have been breeding in most of the yards I've worked in the last several weeks -- those "wrigglers" in an unused garbage can or an open plastic storage box on the side of the house. They can complete their entire life cycle in a matter of days!


Photograph from Mosquito Ecology on the Web site of Los Angeles County West Vector Control District

Maybe you even have an old tire that has caught some water ... I urge you to check around and make sure your yard isn't producing mosquitos. Most people who are don't know it.

There were over 700 reported cases of West Nile Virus in California last year, a new disease carried by mosquitos. There are few human fatalities, mostly elderly or other particularly vulnerable individuals. But it's not pleasant to be sick. Apparently the disease kills horses! I've been hearing ads on the radio for a vaccine.

Use any captured rainwater to water your plants, especially those under the eaves or indoor plants. Any mosquito larvae in the water will die quickly once out of the water -- they are fully aquatic organisms. The nearly mineral-free rainwater helps leach out the salts that build up in the soil from using irrigation water. Captured rainwater is wonderful for irrigation, but one should take care to isolate it from mosquito breeding opportunties!

By the way, something NOT to do: watering your plants with swimming pool water. One client had a megapot planted with a giant chain fern (Woodwardia fimbriata) which has not made normal growth and often seemed burned. I found out why when I was watering it in his presence -- he suggested I do the easy thing and refill the can with water from the swimming pool! Turns out he was consistently filling the watering can with water from his swimming pool, which was so handy, closer than than going to the faucet on the side of the house! Apparently chain fern stands up to considerable abuse, for this has been going on for a couple of years! And no wonder it was much smaller than I expected it to be, and so often presenting burned fronds! Also surviving but not thriving under this abuse was a Vancouveria and western dog violet. Tough plants.

Swimming pool water, with its heavy load of chlorine, is not good for irrigating plants!