This year, I have heard too many farmers say they are waiting for new technologies to solve their weed resistance problems. My response? Upcoming traits will be beneficial for weed control, but none will be a silver bullet or a final cure.
In 2010 I wrote a column about glyphosate resistant weeds. At that time, there were 10 weeds resistant to glyphosate in 22 states. As weed resistance has marched north, we now have more than 15 weeds with multiple resistance among them in the United States.
While the weed resistance story has changed drastically in the past five years, my advice remains the same. Here is what I wrote back in that 2010 article, “With resistance, the first step is identifying whether you have it. If you are not achieving 100% control of the weeds in your RR fields, you need to address why. Was it a coverage issue, a skip, wheel tracks, weather issues or simply surviving plants? If you determine the reason is surviving plants, you have a problem. Just five plants remaining per acre in year one can lead to 400 plants per acre the following year. And by year three, there is potential for 32,000 plants per acre to produce resistant seed.” (October 2010 Dakota Farmer)
These staggering numbers have become a reality for some growers. Peterson Farms Seed has been carefully watching the weed resistance problem gain momentum as it moved into our part of the world.
7′ waterhemp plant found near Buffalo, ND
I have talked with a lot of farmers about planting LibertyLink soybeans for 2016. Liberty is the only non-selective herbicide we have available today in soybeans with no resistant weeds. We’ve worked with the LibertyLink system longer than anyone else in the region – we tested the very first LibertyLink varieties when they were introduced in 2006, and have been testing and growing them ever since.
Farmers must approach weed management proactively rather than reacting to a problem. Another excerpt from my October 2010 column that still rings true today: “The management strategy we need to embrace is using pre-emerge herbicides in corn and soybean fields because: a) early weeds do the most damage to yield; b) a pre-emerge gives timing flexibility with post-applied herbicides; and c) university data has shown yield increases by including pre-emerge chemicals in your program. Another option is tank-mixing other herbicides with glyphosate in your post-applied applications.”
The PRE program worked very well this year in both the Roundup Ready and LibertyLink systems. We need to use PREs in all crops available. Visually, most problem areas are soybeans fields, but I have also noticed some dirty non-soybean crops, which can increase the weed seed bank in our fields. Using companion herbicides adds additional modes of action to your weed management system and helps reduce the spread of these resistant weeds.
We may still be a year away from new technologies due to the export hurdles they have encountered. Even if we achieve some of these approvals, supply will be limited for 2016 planting. In the meantime, familiarize yourself with LibertyLink. Our independent research shows that yields are very similar between RR2Y soybeans and LL soybeans. LibertyLink soybeans are an excellent option with great agronomic characteristics to allow planting across variable soils.
Consider these tips as you’re making your weed management plan and variety decisions for 2016.