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The Good Earth

...West Nile Virus
by Dan Clost
by Dan Clost


First serious garden earned 25 cents from the Kemptville Horticultural Society when I was 12. Have been poor in horticulture ever since but rich in spirit.

Went to work writing the Good Earth column (over 500 articles published in newspaper, magazine, website and journal.) and learned that what was printed wasn't what I wanted to say and certainly not what Gentle Reader understood me to say. Subsequently have developed a certain clarity and economy of words.

Day job- nursery and production manager for a large nursery/garden centre
Side job- Garden restoration and renovations, design consultations, remedial pruning.
Night job- garden writer and communicator (overnight success in another 20 years)

Dan gardens in Canadian Zone 5b

August 17, 2003

Let's take a moment to discuss a potentially serious issue for anyone who spends time outdoors, especially gardeners. We've heard quite a bit about the West Nile Virus (WNV) and it is a cause for concern. According to Ontario Ministry of Health and Long-Term Care there have been 12 birds positively identified with WNV in Hastings County but no cases of human infection; although there have been a minimum of 305 cases in Ontario. There was also one group of mosquitoes within our area that tested positive for WNV. It's clear that WNV has reached our area and we need to be aware of it. It is important that we approach this issue with as much hard information from reliable sources as we can. Expect to see a spate of advertisements soon with prevention methodologies that may or may not be as accurate as the voice-overs want you to assume.

Here's a brief explanation from the MOH:

The West Nile Virus is a mosquito-borne virus that can cause encephalitis (inflammation of the brain). The virus was named after the West Nile region of Uganda, where it first appeared in 1937. West Nile Virus is spread to humans by the bite of an infected mosquito. Mosquitoes become infected by biting an infected bird. The virus is not spread by person to person contact. It cannot be spread from a bird to a human.

The presence of WNV in Canada was confirmed on August 22, 2001 in a bird submitted from Windsor-Essex Country.

As we all know, mosquitoes are everywhere and we have more or less learned to live with them. That laissez-faire attitude is no longer a viable option. We need to consciously take measures to reduce our chances of being bitten by these critters.

The easiest thing to do is to cover up. Lightweight materials make long sleeved tops and full-length trousers less uncomfortable than ever before. Insect repellents are useful but new cautions are being added. For example, one of the best-known products is DEET with a 30% concentration being considered strong. The recommendation now is that you limit applications to 3 times per day. The concern is that with our possible overreaction to WNV we might slather ourselves with products far beyond the manufacturers' recommendations. Read the Labels!! This is especially true with combinations of sunscreen and insect repellents.

You can avoid being out of doors during the times the female is actively feeding between dusk and dawn.

For those of you with water features in your gardens, don't panic. Mosquitoes need still or stagnant water in which to breed. If your system doesn't have water movement, just slip in a wee goldfish or koi. For those of you with vernal ponds, the frogs and toads will do as good a job. Don't leave or allow any standing water on your property if possible, apparently it only takes seven to ten days for a breeding cycle to complete itself. Standing water includes that forgotten coffee can behind the shed, the inside of a tire swing, gardening cans and so on. Take a close look around the yard for these seemingly innocuous items.

Get the bats and birds into the area. Look for a return of the purple martin houses. These can be do it yourself projects but make sure you get the proper dimensions.

Repellent plants, zappers, high frequency sound emitters, and citronella candles all have their proponents. They might have some effect on the insects but not enough to stop them from joining you for dinner. Caveat emptor.

Another promising avenue is the use of Bacillus thuringiensis var. israelensis (Bti) has proven effective. We are familiar with Bt as an organic control for various caterpillar type pests.

Don't let your worries prevent you from enjoying the upcoming gardening season but do take reasonable precautions.


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