The flush of perennial and annual weeds that appeared in late 2021 must be eliminated before seeding, not to mention the herbicide-resistant weeds that may germinate this spring. Here’s a look at some tools for the best pre-seed burndown possible.
“After harvest in late 2021, some growers across the Prairies saw a sea of green in their fields,” says Graham Collier, portfolio manager for Canada with Nufarm Agriculture. “The rain in some areas caused weeds to germinate, making it very important to plan out your pre-seed burndown carefully to get a clean start to seeding. Spring is very busy, so now’s the time to make comparisons between the newest products and plan your strategy for success.”
Increasing herbicide resistance across the Prairies is another critical factor in making the right choice of products for the best burndown possible before seeding cereals, canola, pulses and soybeans. “Growers need to be aware of all the tools at their disposal,” says Collier. “The number of weeds that are resistant to multiple herbicide groups is growing, making pre-seed burndown products with multiple modes of action an important option to reduce selection pressure for herbicide resistance and increase overall weed control.”
Products with these capabilities amplify the power of glyphosate and also slow herbicide resistance, explains Mike Bender, Nufarm’s technical services manager for Western Canada. On the flip side, products with a single active ingredient have a spectrum too narrow to control the growing range of weed populations out there right now.
“The widespread adoption of glyphosate-tolerant canola, and the alarming spread of glyphosate- and Group 2-resistant kochia, have dramatically reduced the effectiveness of glyphosate-only control programs,” Bender explains. “There’s no certainty anymore that the volunteer canola or kochia on a given farm can be controlled by glyphosate alone. So, we need to use control options that will protect the viability of glyphosate and glyphosate-tolerant crops, with modes of action that do not include only Group 2 chemistry and glyphosate. In BlackHawk®, we’ve combined a Group 14 herbicide in a pre-formulation with a Group 4, so it gives you faster, more complete weed control in burndown before cereals, soybeans and corn compared to glyphosate and Group 2 herbicides.”
Four tank-mix products with glyphosate
In addition to BlackHawk, Nufarm’s pre-plant burndown products include CONQUER® II, GoldWing® and ThunderHawk™. All four products can be tank-mixed with glyphosate and need no additional surfactants. The Nufarm portfolio has a pre-seed option for use across every crop in Western Canada.
“BlackHawk has been a solid burndown option for farmers when growing cereals for quite some time,” notes Collier. “ThunderHawk is a new option for the black and dark brown soil zones where growing conditions vary in the spring and longer residual control of volunteer canola is important.”
ThunderHawk has four modes of action (Groups 2, 4 and 14) when tank-mixed with glyphosate for use ahead of cereals. It controls Group 2-resistant weeds (cleavers, wild mustard, redroot pigweed and kochia), Group 4-resistant kochia, and glyphosate-resistant broadleaf weeds (kochia, all types of herbicide-tolerant volunteer canola). ThunderHawk can be applied before and up to two days after seeding barley, oats, and wheat (spring, winter).
“In BlackHawk®, we’ve combined a Group 14 herbicide in a pre-formulation with a Group 4, so it gives you faster, more complete weed control in burndown before cereals, soybeans and corn than glyphosate and Group 2 herbicides.”
Mike Bender, Nufarm
“When building out the product concept for ThunderHawk, we were looking for something that met three main objectives for pre-seed weed control in the black and dark brown soil zones,” Collier explains. “It had to be fast-acting on a wide spectrum of broadleaf weeds. Secondly, it needed to provide residual activity on volunteer canola. Then most importantly, it had to offer multiple modes of action to help manage weed resistance. This product will help farmers manage those tough weeds like narrow-leaved hawk’s beard, kochia and hemp-nettle, and get ahead of herbicide resistance in the black and dark brown soil zones where Group 2-herbicide resistance is growing.”
CONQUER II was designed for combining with glyphosate for burndown ahead of seeding canola. Seeding can take place immediately after an application or CONQUER II can be applied up to three days after seeding. It controls all Group 2-, Group 4- and glyphosate-resistant biotypes of volunteer canola, kochia and cleavers.
GoldWing is another option that contains two modes of action, Group 14 and 4. It provides exceptional weed control, use rate flexibility and outstanding crop safety when used prior to seeding or up to three days after planting pulses and cereals.
Beyond using herbicides with multiple modes of action, here is a checklist to ensure your weed control goes as well as possible this season:
- Change up your herbicide application timings or include an application timing you haven’t before.
- Check over your crop rotation to maximize the benefits that this can provide.
- Test survivors. After spraying, find any patches or individual weeds that were not controlled and have them tested for resistance through your provincial program. This not only helps weed management on your farm, but helps your peers and helps provincial specialists help everyone.
- Keep thorough records. Knowledge is power.
“With the right crop management practices and maximizing the best burndown tools possible,” says Collier, “growers will increase their peace of mind when they go to seed this spring.”
