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New herbicide registrations in forage and turf seed crops

Minor Use registration is working in forage and turf grasses.


November 15, 2007
By Bruce Barker

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On small acreage crops, where herbicide companies have little hope of recovering
their herbicide registration expenses, herbicide choices are often limited.
As a result, a new Minor Use registration process was set up by the Pest Management
Regulatory Agency (PMRA) to streamline the herbicide evaluation process. While
the new process is only a few years old, at least in forage and turf grass the
process is working.

"The whole idea is to try to get registration of products, or add crops
to labels, in crops where it doesn't pay pesticide companies to do the work,"
explains weed specialist Dan Cole with Alberta Agriculture, Food and Rural Development's
(AAFRD) Crop Diversification Centre North at Edmonton. "We have a turf
seed group that is quite active in western Canada in developing applications
for minor use, and we have been relatively successful."

Cole and others in the group, including scientists at Agriculture and Agri-Food
Canada, the British Columbia, Saskatchewan and Manitoba departments of agriculture,
forage seed associations and industry, work through a planning process that
first identifies which weeds are issues in forage and turf grasses. For example,
immature cleavers seed is difficult to clean out of grass seed. Herbicides that
have the potential to control cleavers are identified, such as Prestige, Attain,
Spectrum and Unity.

The next step is to compile herbicide tolerance information from the Canadian
Weed Science Society (CWSS) and other sources. The group may also conduct its
own trials if necessary.

Forage seed crop Herbicide
Tall fescue –
established
Prestige for control of a wide range of annual broadleaf
weeds including cleavers, and perennials like Canada thistle and dandelion.
Tall fescue –
seedling and established
Attain for control of a wide range of annual broadleaf
weeds including cleavers.
Annual ryegrass – seedling Assert for control of wild oats, stinkweed and mustard.
Alfalfa
seedling

Tropotox Plus for control of a wide range of annual
broadleaf weeds and suppression of Canada thistle.
Alfalfa
seedling and established
Odyssey for control of a wide range of annual broadleaf
and grassy weeds including cleavers and stork's bill.

Cole cites two examples where trials were invaluable in screening herbicides
for forage seed crops. The first was Ally herbicide, which can cause very noticeable
stunting to established timothy, but seed yields may not be affected.

On the flip side, although Accord does not usually cause visible injury to
chewings fescue, there can be a significant reduction in seed yield. It should
be noted that Accord is no longer available in western Canada, but the example
shows the value in the research conducted by the group.

Based on the compiled data, if a herbicide looks promising, the group will
apply for Minor Use registrations. The pesticide company has to provide a letter
of support for the registration, and will usually agree to the registration
once PMRA and the pesticide company have had a chance to review the data.

Cole cites an example where Achieve used on established meadow brome grass
averaged nine percent crop injury in five trials, ranging from zero to 19 percent.
"If the research shows that crop injury rises above 20 percent, you have
to be careful because that is a good indication there will be injury in the
field. Nine percent injury over five trials looks pretty good, though."

Recent registrations to forage seed crops
In the past three years, five new Minor Use registrations were added to herbicide
labels for use in forage crops grown for seed. Cole says the registrations are
proof that the system works for farmers.

Cole says that the group has submitted data on seven further Minor Use applications.
The group submitted a Minor Use application to get timothy grown for seed added
to the Curtail M label, for control of annual broadleaf weeds as well as Canada
thistle and dandelion.

In addition, the group supplied data for six other submissions that were already
underway through the Minor Use Herbicide Priority System. The Priority System
identifies the more critical minor uses and fast-tracks them through the system
by having the trials conducted to collect any missing data needed for registration.
This brings new registrations to market more quickly, providing they meet all
necessary regulatory requirements.

These submissions include Prestige and Spectrum herbicides for use on timothy
for seed; Prestige, Attain and Spectrum for use on creeping red fescue grown
for seed; and Spectrum for use on tall fescue grown for seed.

The forage seed group continues to develop and compile data for further herbicide
submissions. They are researching PrePass for use as a pre-seed burndown prior
to planting grasses. Weeds controlled would include many annual broadleaf and
grassy weeds, plus dandelion seedlings up to the five leaf stage.

Other work is also in the development stages and Cole is optimistic that they
will be able to continue to expand the herbicide choices in forage and in turf
grasses grown for seed. "In the end, the new Minor Use process should save
us money and will help to add forage seed crops to labels, which will provide
the tools required to grow them more profitably in western Canada." -30-