CCC Blackleg and canola rotation

[wd9]

It may not be an issue as our almost continuous use of canola will quickly swallow up these limited resistances available for blackleg.

Should the CCC be more vocal or more steadfast, not sure the wording, in the minimum 3 year or more rotation rather than provide guidelines or almost quietly agree with a short rotation?

[JurkeCCC]

Good points.

The first one about resistance failing.
There is always a risk that a super race
of L. maculans may be selected that none
of our resistance genes work against.
But in reality, judging from the
experience in Australia (where blackleg
is much more severe), there are huge
swings in the L. maculans populations
from one race to another in a field
simply depending on which variety is
grown. There is data now showing that
resistance that did not work in one year
suddenly works great again five or six
years later. So the solution of rotating
resistance genes seems to give very good
control. The theory and the practice
seem to match up well under the very
harsh blackleg conditions of Australia.
There is no reason to think that it
would be any different in Canada.

Your second point about whether the CCC
should be providing tools for tight
rotations is kinda of a philosphical
point. But I think the CCC is taking the
right approach - our first
recommendation for blackleg control is
still to use a long rotation. The
message about rotating varieties is a
new one, so it likely is getting a lot
more air-play right now than the long
rotation messaging, I guess. But the
rotating varieties message is not our
first recommendation. Economics arguably
has the strongest influence on grower
planting decisions, (which the CCC has
no control over), so growers need to
have the information available if they
find themselves faced with dealing with
tightened rotations. But your point
about us being more vocal on the long
rotation piece is a fair one to make.

Thanks for the discussion, wd9.

Clint

[wd9]

Thank you Clint for taking the time to post this stuff. I appreciate it.