Things you need to know about weed control

Now here is something you really don’t want in your field. No, I’m not talking about Kelly Bennett, portfolio marketing leader, cereal herbicides with Dow Agrosciences (pictured left).

I’m talking about the very robust wild buckwheat plant he is holding. Bennett, a Saskatchewan farm boy who has been with DAS for 25 years, made the very simple point, during a recent tour of DAS crop protection demo plots – the primary purpose of your herbicide program is to get rid of weeds like this wild buckwheat, as well as kochia, cleavers, hemp nettle, lamb’s quarters and probably a few dozen more common weeds that all can affect crop yields for Western Canadian farmers. You don’t want this mess robbing yields and snarling up your combine header.

The program usually starts with a pre-seeding burndown with a glyphosate product, but then follow that up with the proper in-crop herbicide treatment. Know your weed spectrum, use the proper product, at the proper application rate, with the proper timing and then as Bennett demonstrates (photo at right) more of your weeds are going to look like this instead.

DAS describes themselves as the Solutions People. They are not just selling chemicals, but weed control solutions. They are putting money into research and development, field testing and extensive demonstrations to find products that work and then show producers how well they work, often in comparison with other leading products.

As Bennett and Len Juras, former Sask Agriculture weed specialist, who is now a weed scientist with DAS, pointed out on this tour — there are no silver bullets out there. Glyphosate, when it was first introduced, was perhaps considered a silver bullet — the big fix for all your weed problems. Well, it isn’t. It is good and effective in a lot of situations but it can’t do it all. And just like every other herbicide or chemical on the market there is concern now about development of glyphosate-tolerant weeds. So even if one chemistry is good, you just can’t hammer the weeds year after year with the same product.

NEW APPROACH TO HERBICIDE TOLERANCE

DAS, like other companies, are now developing more dual action or tandem herbicide products. One objective of combining two products such as Simplicity and Attain, Simplicity/Frontline/24D, Tandem/24D ester, or Simplicity and a new version of Attain being called Octtain (registration is in the works), is to cover a wider weed spectrum and give producers more options. But, perhaps even more importantly is to combine two products with different chemistry effective on the same weed, to reduce the risk of developing herbicide tolerance. 

In recent years there has been a lot of emphasis by weed and chemical people on rotating herbicides — different modes of action — to prevent herbicide tolerance. Use a Group 2 herbicide this year to control wild buckwheat, for example, and then use a chemistry from a different group next year to nail any of those wild buckwheat plants that escape.

Now the preferred thinking is to combine two products so if a few smart weeds appear to be tolerant to one chemical, the other one will get them — sort of a one/two punch.

As Juras (pictured below, left) explains, researchers are finding there is a synergy in combining two products with different modes of action in one application. If one product is 75 per cent effective in controlling a weed, for example, and the other product is 80 per cent effective, by combining the two, producers are seeing 95 or 98 per cent weed control. It is not fully understood how or why it works, but the main point is that it does work.

Like developing new canola varieties, it is a long process in developing new herbicide chemistry. DAS has a Discovery Centre in Indianapolis where they may screen 100,000 different chemistries each year to find a few that may just have an inkling of potential for controlling a certain weed. Those few are then introduced into a research program for further testing in various parts of the world. Duds are booted right away, but with each trial, any that show greater promise are moved along and measured for every possible positive or negative impact on the crop or the environment. Getting a chemical from the Discovery Centre to a fully registered product ready for producers can easily take 10 years. The cost of the process doesn’t add up quite as quickly as the U.S. debt, but it is expensive.

And a final note on weed control — just when you might think

 all the bases are covered, something new shows up.In these two photos, Rory Degenhardt (right), an Alberta farm boy, also a weed scientist with DAS, shows a relatively new weed he’s found in certain parts of Saskatchewan called Marsh Willow Herb. It is not difficult to control but it is appearing. It likes bogs (i.e. much of Saskatchewan this year) but on the upside the leaves are edible. So it affords itself to an integrated weed control strategy — spray and/or snack.

Lee Hart is a field editor for Grainews in Calgary, Contact him at 403-592-1964 or by email at lee@fbcpublishing.com