Features Agronomy Weeds
Effectively control volunteer canola

Getting tough on hard to control weeds is not easy. In 2007, a new herbicide gave a ‘one two’ punch to seemingly immovable weeds, such as volunteer canola, kochia and dandelions. A packaged tank-mix of glyphosate and carfentrazone, a new chemistry, provides quick burndown while also controlling volunteer glyphosate tolerant plants.

“We view CleanStart as a premium product for high value crops, such as canola, potatoes, sunflowers and peas,” says Brent Zacharias, the marketing manager for Nufarm, the manufacturer of CleanStart. “There was a need for better weed control prior to seeding, particularly in reduced tillage or no-till operations, and because CleanStart can be used in advance of seeding, the field will be ready for putting in the new crop.”

CleanStart fulfills the need for better volunteer canola control before seeding. Photo By Bruce Barker.

The improved weed control, faster burndown and lack of residue caused some excitement in the fields in the spring of 2007, he adds, and supplies of CleanStart quickly sold out. The label indicates that CleanStart is registered for use prior to barley, dry beans, canola, chickpea, corn, flax, lentil, oats, pea, potato, sunflower and wheat.

A product like CleanStart was needed, according to Eric Johnson, a researcher with Agriculture and Agri-Food Canada at Scott, Saskatchewan. “Growers needed something to control volunteer, particularly herbicide tolerant, canola,” he says. “There are other options available, but we found this tank-mix is a much safer product for following broadleaf crops.” He explains that when he tested CleanStart, he applied it at a high rate before seeding lentils and any residue that was found was negligible. However, he still cautions growers to use CleanStart wisely and be sure to apply it at the right time to get maximum control.

Carfentrazone is a new Group 14 chemistry and, as such, is the first herbicide in this group that is available to western Canadian growers. It has proven effective on kochia, which is resistant to Group 2 products. “Because of the new chemistry, CleanStart can help break resistance cycles,” Zacharias explains. Registered weeds include those controlled by glyphosate, plus rapid burnoff of chickweed, dandelion, shepherd’s purse, tansy mustard and all volunteer canola including herbicide tolerant varieties.

Nufarm worked with growers to learn how CleanStart could be used most effectively. There were three key areas that growers reported to be imperative when using the new product. Carfentrazone is a contact herbicide and growers who tested the product recommended that a fine droplet size be used to ensure complete coverage of the weed. “We’re working on improving our recommendations for 2008 based on this information,” Zacharias says. “By using a finer droplet size, we can see a 30 percent improvement in control.”

The grower-testers also suggested, as does Johnson, that weeds be no more than four inches tall when spray is applied. For dandelions, the recommended stage was at the three inch rosette stage. “CleanStart has to be applied when the weeds are small,” recommends Johnson. “It’s just not as effective when applied after the four leaf stage in canola.”

The growers who tested CleanStart observed that seeding could be done soon after application, which encourages earlier crop establishment. “There was 90 percent or better control within three to seven days after application of CleanStart,” explains Zacharias. He adds that the ‘speed factor’ was a ‘crowd pleaser’ as growers were able to get to the important task of seeding sooner.

As with any new product, it is important to use it properly, although issues with resistance developing are minimized because two chemistries are in play. Johnson says, due to its specialized nature, it is unlikely CleanStart will be used concurrently, which will also help reduce the chances of resistance developing to the new chemistry. “This is an effective product when used appropriately,” comments Johnson. “Growers have to be aware of the timing of application.”

It is always exciting when new products are introduced that live up to their initial promotional materials. Based on the enthusiasm of the growers who tested it, CleanStart looks poised to fulfill its promise. -end-