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The Good Earth
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

June 15, 2003

Both sides of the pesticide issue trot out impressive and contradictory results citing similar studies. Both suggest strategies for responsible and prudent care of our environments, which are quite different from the other.

For the record, I am not opposed to the use of chemical pesticides if warranted. However, with the exception of a one-time herbicide application over ten years ago, we do not use pesticides other than insecticidal soaps. (Our favourite herbicide is left over hot water from corn roasts poured onto the offending weed.)

One of the terms used to evaluate the need for intervention is threshold. A threshold is that point of infestation or occurrence of a pest with which you are no longer comfortable. This level varies with the individual. How you intervene, not when, is the crux of the issue. Do you use Merit (the trade name for imidacloprid that is registered for use on lawns) to control grubs? There are studies suggesting that imidacloprid (Gaucho when used on sunflowers, Admire when used on potatoes) has serious effects on honeybees. There is an equally impressive counter-study showing the opposite. It appears the discerning point is the residue level of the insecticide on pollen. The Canadian Honey Council requested that the Minister of Health and the Pesticide Management Regulatory Agency withhold the registration of imidacloprid until unbiased research is completed on the residual and sub lethal effects of systemic insecticides on honeybees. This request was denied because there have been no adverse reaction reports submitted by Bayer. The PMRA has indicated that they are monitoring the situation and will consider the effect of systemic insecticides on bees when determining new registrations.

For homeowners, is this a valid issue since we don't grow crops in our back yards? Are bees foraging on our lawn during suggested application times?

If broadleaf weeds have invaded your greensward do you use 2,4-D, which is the primary herbicide in most available formulas? How safe is 2,4-D? A Dupont study conducted over several decades involving workers manufacturing the product show an almost identical mortality rate and Non Hodgkin's lymphoma incidence to national averages. In other words, no effects.

An issue was raised concerning the safety of the "inert" components of these formulations. These are non-pesticidal compounds present in the mixture. For 2,4-D, the inert compound is water.

Here are my suggestions. Invest some time in your bit of this good earth and learn its characteristics. Follow integrated pest management outlines. Grow a proper lawn and you won't need to worry about a lot of these problems: read Landscape Ontario's guidelines for Healthy Lawns. If there is a weed you don't like, pull it out. If weeds persist, decide if growing a lawn is a viable option. Maybe your front yard should be a wild-flower meadow.

Identify the problem bug. Is it the real problem or indicative of something else? What is the most benign response? What happens if you don't do anything?

Most importantly, if you have a problem, contact a professional. You'll find them at nurseries; garden centres, organic societies, government offices and working for lawn care companies.

For me it boils down to a few simple questions. How much trust do we put in our governments and scientists and their abilities to keep our environment and us safe? (A lot) Should it be a blind trust? (Never) What would be the effects of a comprehensive pesticide ban? (Devastating) How will the homeowner respond to such a ban? (They will circumvent it.) What other methods would they employ? (Never fail to underestimate our ability to devise the most dangerous and stupid way to kill a pest. A Haligonian poured gas on the lawn and lit it.) How would you enforce such a ban? (You can't.)

Bottom line: it is a value judgement, yours.

Note to readers: if you are interested in any of the facts or references mentioned please contact me.

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