Taken from Eclectic Gardener @ http://www.teachinggarden.org/
written by Alan R Hickman

While all the concern has been focused on the H1N1 flu bug, another organism, one which has recieved scant media attention, has been quietly gathering strength and taking its toll on basic food crops across eastern North America.

Phytophthora infestans likely means nothing to most readers; but, it is the organism which causes'late blight' of potatoes and tomatoes, and which triggered the Irish potato famine in the 1840/50's.

As a life-form, P. infestans belongs in that microscopic netherworld between animals and plants, not properly being one thing nor the other.

Now technically classified as Oomycetes, P. infestans was traditionally considered to be a fungus and it does respond to control by fungicides.

Like most disease and pestilence explosions, the makings for late blight outbreaks have been around since forever - suitable weather, plus infectious organism, plus, of course, politics.

The cool wet Irish climate was as close to perfection as any moisture-loving animalcule could dream of.

Add a nineteenth century population living in abject poverty, dependent almost solely on a single crop for food, and impose a political system offering no support, relief or hope, and it is only surprising that just one million died.

In the northeastern states and provinces, 2009 is being called 'the year without a summer'.

The overall low temperatures and the dewy predawn hours have been, if not exactly Irish, at least very conducive to happy molds, funguses and sundry other lovers of damp and humidity.

The sociopolitical connection to the current outbreak of disease results from what can only be described as a growing swell of paranoia related to things governmental and scientific.

When numbers of people refuse to let their children hear a school broadcast, because they believe that the President of the United States is going to indoctrinate the kids with communism, what other word is there but paranoia; viz. a tendency on the part of individuals and groups toward suspicousness and distrustfulness of others that is based not on objective reality.

A probable upsurge of late blight had been predicted by the various state-government departments of agriculture and by OMAFRA (Ontario Ministry of Agriculture Food and Rural Affairs), and warning had been served to growers that "applying effective fungicides is extremely important".

For the most part, fungicides work as a prophylactic; they need to be applied before the organism has taken hold.

Once plants show signs of infection, it is too late and the infected plants can only be culled.

The first reports of late blight in Ontairo came in early July and, since then, throughout the province a substantial acreage has been lost to the disease.

Peel Teaching Garden, tucked away in a back corner of the Brampton fairgrounds and far away from any large commercial potato or tomato operations, managed to dodge the bullet for quite awhile.

The potatoes came through mostly unscathed; but, a couple of weeks ago, the wind-borne spores had settled in and, in a matter of two or three days, the entire crop of large tomatoes had been destroyed.

The recent demand by some consumers for vegetables grown using so called 'chemical free' methods, and the outright banning of chemical pest-control products in some jurisdictions, has left large and small pockets of unprotected crops throughout North America.

As P. infestans is highly contagious and, under favourable wind conditions, can travel tens of kilometres in just a few hours, the degree to which these unprotected areas have exacerbated the spread of crop damage is open for debate.

For the future, OMAFRA is now advising farmers: "Fields should be selected away from potential sources of the disease such as backyard gardens where tomatoes and potatoes grow without the use of fungicides."

Home gardens have now become significant reservoirs for disease and pests.

In the greater scheme of things, a few thousand acres of lost production in Ontario won't create a famine - we can always import a few more tons of produce from Mexico - and Peel Teaching Garden's 900 square feed of tomatoes doesn't amount to so much as a burp in a hurricane.

On a local scale though, the picture is quite different.

Last year, the garden volunteers harvested 100 kilos of tomatoes, and, in 2007 , 200 kilos of tomatoes, for the Knight's Table kitchen and food bank; so this year's total crop-loss will put a major dent in the garden's contribution to the less fortunate in this City.

When faced with the threat of swine flu, you can wash your hands and get a flu shot and at least have the illusion of doing something.

Thanks to the influence that science-challenged pressure groups now exert on all levels of government, if you are a home gardener facing pest or disease problems, you can just wash your hands and go buy your produce at a grocery store.


RE: The Eclectic Gardener by Alan Hickman.
Response to this article from Bette-Ann Goldstein

As a backyard gardener in Brampton who avoids using fungicides, pesticides, and herbicides, I was very disturbed by you blaming me in your Sept. 23 column for the loss of your tomato crop to phytophthora infestans.

I didn’t have any sign of this disease in my tomatoes this season, nor did any of my friends and neighbours in Brampton and Caledon (none of whom use fungicides etc.) have it in their potatoes or tomatoes.

My research on the Internet says that it is usually spread by the use of potato culls from previous harvests, rather than spores blowing in the wind.

It’s puzzling that your potatoes escaped, while the entire tomato crop collapsed.

You have my sympathies— but such are the joys and disappointments of gardening.

High Temperature:
Actual: 22°C sun and cloud rain 2.3mm Wind WSW20km/h P.O.P.24%
Average: 19°C
Record: 31°C in 1959

Low Temperature:
Actual: 12°C mainly clear Wind NW16km/h P.O.P.20%
Average: 8°C
Record: -1°C in 1974