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Understanding fungicides blocks increased wheat production

New chemistries require new learning curve.

November 13, 2007
By Ralph Pearce


18aDuring the summer of 2006, those keen on seeing an increase in Ontario wheat
production were buoyed by forecasts for new uses, new export opportunities and
higher demand from millers and processors.

Yet a lack of familiarity with fungicides and their perceived value to wheat
production likely will impede growers as they try to increase their acreage
across the province. That, according to Pat Lynch, field agronomist with Cargill.
It was June 2006 when he made that statement to a gathering of wheat growers
and dealers and 12 months later, he maintains that growers understand how to
use herbicides and insecticides, but are still unclear on fungicides.

"In some ways, you have to look at fungicides as fire insurance, where
you pay the premium, and then a good day is that 'I didn't have to use my fire
insurance because there was no fire'," he explains. "Similarly with
a fungicide, if you spray it and there's no difference between the check and
the spray, that's the good news, because there was no disease. The fungicides
that we are working with now are protectants, so if we spray before the disease
comes in, or if the weather afterwards is not conducive to that disease, we
see nothing."


Another point where the perceived value of a fungicide suffers is its inability
to eradicate a disease, nor do they have the residual effect of many herbicides.
"If you put on a fungicide, you're buying days or maybe a few weeks of
protection," says Lynch, who is based in Stratford, Ontario. He also notes
there is a level of familiarity with weeds that does not yet exist with diseases.
"Many growers have a concept of an annual weed, of a perennial weed, of
a grass or a broadleaf, but we're just on the edge of starting to get some disease

Weeds vs. disease: different worlds
To be fair to growers, Mike Cowbrough insists the agri-food industry is at the
same point with diseases and fungicides as it was 20 years ago with weeds and
herbicides. And he agrees with Lynch's assessment of familiarity with weeds
as opposed to insects and diseases. As weed management specialist with the Ontario
Ministry of Agriculture, Food and Rural Affairs at the University of Guelph,
Cowbrough concedes growers have become accustomed to dealing with weed control,
including identification and a basic understanding of modes of action.

"We know the impact that weeds have on yield; they're very obvious and
they are easier to scout for," he says, noting that yield losses in an
untreated field can climb by 70 to 80 percent. "With insects and disease,
we'll never get that high unless there's a catastrophic effect and then it's
more of a quality issue, and that's a lot more difficult to illustrate, sometimes."

Changes are prompting a shift in perceptions of fungicides; changes in climate,
in agronomic practices and the migration of pests and diseases are likely to
force growers to learn more about fungicides, their properties and applicability.
Soybean aphids have become an annual pest issue for growers throughout much
of Ontario and western Quebec; bean leaf beetles are showing signs of increasing
their frequency and severity, while take-all in wheat, leaf and stripe rust
and fusarium are all suggested to be on the rise. "Traditionally, the crops
have been fairly easy to manage around the insect and disease side because they
didn't have an impact," relates Cowbrough. "But the bigger question
from my perspective is why are we seeing more of these problems? Is it rotation?
Is it climate? Is it management?"

With many of the diseases and insect pests, the causes can be traced to regional
influences, including soil type or environment. Yet weeds are not particular
to soil type or environment, where pests and diseases are.

Nothing new for herbicides, plenty to come in fungicides
Another factor that will play into the uptake of fungicides is the continued
availability of new chemistries. Early in the 2000s, various researchers cautioned
growers that limited returns on investment were affecting research and development
on new herbicides. In short, there were no new glyphosates or Group 2 herbicides
to help growers. Such is not the case with fungicides, and as diseases and insect
pests continue to migrate north and east, development of new fungicides will
become increasingly important to more growers.

Lynch talks about the move of some crop growers into the horticultural sector,
with a resulting learning curve where fungicides are concerned. Where there
is a particular worry is in the licensing of newer chemistries already in use
in parts of Europe and the US. "Some of the fungicides that are available
to other growers in other parts of the world are superior to what we have here,"
says Lynch, adding that Canadian growers are losing money to bureaucratic restrictions.
"Our licensing system will not allow some of those other fungicides to
be used in Canada."

Two groups, two approaches
As someone who regularly tests fungicides for their efficacy, Dr. Art Schaafsma
agrees with Lynch's assessment, adding there are two distinct groups of growers
in Ontario. One side considers wheat to be little more than a rotational crop,
content to reap the best price from Chicago, while the other group sees it as
a crop that derives special premiums and opportunities. What sets the two apart
is a value assessment on the crop.

"There are enough wheat growers that will put it in and see what happens
and they might, on the advice of a supplier, spray or have somebody look at
their wheat," explains Schaafsma, a professor at University of Guelph's
Ridgetown College campus. "Then there are those who understand what wheat's
worth to them, and understand fungicides, so they've made the evolution."

There are some who insist fungicides are part of a new learning curve and that
time is a rare commodity among growers that challenges their adoption of new
chemistries. Yet, Schaafsma insists he knows of several larger-scale producers,
including one that has added a livestock component to his cropping practices.
And he has made the adjustment where fungicides are concerned. "It's a
matter of understanding the value," concludes Schaafsma.