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Weed Control Options In Mustard Still Limited

A fall application of glyphosate is of tremendous benefit in reducing the populations of perennials such as Canada thistle and dandelions, winter annuals, and even kochia

Venture YELLOW MUSTARD BROWN/ORIENTAL MUSTARD

Registered

Assure II

Avadex

Clethodim

Edge

Fortress

Poast

Trifluralin

Venture Not Recommended

Muster Gold

Muster Toss-N-Go Registered

Assure II

Avadex

Clethodim

Fortress

Muster Gold II

Muster Toss-N-Go

Poast

Trifluralin Not Recommended

Edge

For years mustard growers have struggled to manage broadleaf weeds in their mustard crop. Mustard is a relatively competitive crop, however there are few registered options in Canada to manage broadleaf weeds. Kochia in particular has become a major limiting production factor for many mustard growers.

Mustard isn’t seeded on huge acres, meaning it doesn’t attract big research dollars or attention by chemical manufacturers. It is a vicious circle: mustard is a small acreage crop which makes chemical manufacturers less likely to throw research dollars in to i, and the lack of weed control options in mustard makes producers look at other crop alternatives that have more herbicide options, thus limiting acreage. Western Canadian farmers are lucky to have a few dedicated researchers at Agriculture and Agri-Food Canada’s Scott Research Station on hand to evaluate products for potential minor use registration.

WATCH FOR GROUP 1 RESISTANCE

Mustard growers are familiar with the registered herbicides available to them. There are numerous herbicides available for wild oat control in all types of mustard, however, be aware that many of these products are group 1 products. If resistance to group 1 is a concern, control of wild oats can only be obtained by a granular pre-seed product.

The real weed control gap for mustard growers is for some hard to control broadleaf weeds. Unfortunately the list of weeds that mustard growers indicate as a problem is the same as those weeds with very limited control options available: kochia, wild buckwheat, Canada thistle, stinkweed and cleavers.

Because of the lack of weed control options available to producers, it is very important that producers plan for success for their mustard fields. A fall application of glyphosate is of tremendous benefit in reducing the populations of perennials such as Canada thistle and dandelions, winter annuals, and even kochia.

EVALUATING UNREGISTERED OPTIONS

Researchers and scientists are continuing to look at different products that may have a fit for mustard production in Saskatchewan. Trials concerning a number of products and application times have been conducted at the Agriculture and Agri-Food Canada (AAFC) Research Centre at Scott, Sask. The following chemicals are not registered or recommended for use on mustard. These trials are for evaluation purposes only. Scientists with AAFC in Scott are continuing to screen these chemicals to determine their merits for kochia control as well as monitoring any crop injury that may occur. Work like this is necessary

to build enough data to one day, potentially, receive minor use registration.

1) Lontrel

Lontrel has been applied in trials of mustard with mixed results. Although this is not a registered practice some findings have come to light:

Yellow mustard is more tolerant than either brown or oriental mustard Crop damage resulting in yield decreases were seen at 0.17 litres per acre (lowest registered rate on canola). Losses were 9 per cent on yellow mustard and 22-23 per cent on brown and oriental.

Less crop injury was seen when applied at the four-leaf stage compared to the 10 leaf.

SOURCE: Internet-Saskatchewan Mustard Development Com-mission Blackshaw and Loepkky, 1994

2) Authority

Authority (sulfentrazone) is a registered product on chickpeas for western Canada that has shown very strong control of kochia, wild buckwheat, and red root pigweed. FMC is currently pursuing registration in the United States for use on flax, field pea and sunflowers. According to Dan Ulrich, researcher at AAFC Scott, variable results have been seen in trials with mustard. Trials involving Authority for 2010 are being planned to help determine if this product has a fit with mustard production, specifically yellow mustard. Trials will be completed to determine best time of application (prior to crop emergence in the spring or in the fall), to evaluate kochia control, as well as potential crop injury. The application of Authority is also going to be evaluated on its own as well as in combination with Edge and trifluralin both in spring and fall.

3) Proponit

Proponit (propisochlor), manufactured by Arysta LifeSciences, is a product that is not yet registered for use in Canada, however it is approved for use on a variety of crops in Poland and Hungary. Plans are in place for 2010 at the research station at Scott to evaluate whether this product has a fit for application on oriental and yellow mustard in western Canada. This product will be evaluated as a post-emergent product. This product was looked at in 2009 with little control seen on kochia, wild buckwheat, and lamb’s quarters. According to Ulrich they will continue to screen this product in 2010 in combination with Muster to determine both kochia control as well as crop tolerance.

4) Cadet

Cadet is another product that will be screened for trials at the Scott research centre in 2010. Cadet (fluthiacet-methyl) is a product that is registered in the U. S. for use on corn and soybeans. Cadet will be looked at for use as a post-emergent product and evaluated for broadleaf weed activity.

Although herbicide options for mustard crops in Saskatchewan are limited, it is encouraging to see the research work that is being completed in Scott as part of the Minor Use registration program. The efforts surrounding these trials seem to be concentrated on looking for answers for controlling one of the most bothersome weeds in mustard, kochia. All of these products that are being screened are of different chemical groups which may offer some reprieve to controlling the high percentage of the kochia populations that are resistant to group 2 chemistries.

Although our registration process in Canada can be very long and arduous, it is exciting to see work continuing on a small acreage crop like mustard to address real production problems that producers are facing. Stay tuned later this fall to hear if any of these products are showing merit for controlling kochia in our mustard crops.

Bobbie Bratrud owns and operates Bratrud Ag Advisory Services (www.bratrudag.ca)with her husband Mark. They also farm at Weyburn, Sask.

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