Tthe last new herbicide mode of action was the HPPD inhibitors like Calisto and Balance in 1985. There are no new modes of action on the horizon. We do not need just one new mode of action, we need at least two and they are not in sight.
I just returned from the national meeting for weed scientists. It was a great meeting with a lot of excellent presentations. While a major emphasis at the meeting was on herbicide-resistant weeds, I was disappointed by the lack of emphasis on proactive resistance management.
In fact, a prominent weed scientist, whom I have the utmost respect for, made the statement that it was too late for proactive resistance management — that the cows had already left the barn. If he is right, farmers had better be on the lookout for a new profession. We must be proactive… in every field beginning this year. We can attempt to salvage what we have and go forward with a different approach.
As a society, as an industry and as farmers we have simply gone down a path of using a herbicide until it did not work anymore and then figuring out Plan B. I have been right in the middle of it. We have always had Plan B available in the next new jug or in the next new trait.
However, the last new herbicide mode of action was the HPPD inhibitors like Calisto and Balance in 1985. There are no new modes of action on the horizon. We do not need just one new mode of action, we need at least two and they are not in sight.
Glyphosate has failed on the driver weeds due to lack of diversity in our weed management programs and the fact nobody has been willing to change programs until it was too late.
Now we have the LibertyLink, which is excellent technology. Preserving the effectiveness of glufosinate (Liberty or Ignite) and the LibertyLink technology is critical to weed control for the near future. What are doing with that technology? Essentially everything we can do drive it off the cliff before we get a chance to find out how really good it is. We are only switching to this technology after glyphosate has stopped working, continuing our pattern of using up one technology and going to Plan B. And first-year users often struggle because they try to use it like they used glyphosate in Roundup Ready crops —with no diversity in the program.
How long will the technology last under these circumstances? My fear is not long enough. We cannot seem to get to the next step — switching systems, adding diversity or switching cultural practices in fields where what you are doing is still working fine. Once the first signs of resistance appear it is a snowball effect from there.
In Arkansas and across the Midwest, growers tell me what they are doing and that it is working fine. I politely just say, “Then please change your program now.” If you are in to farming for the long haul, that is where you have to get to.
It so critical to preserve glufosinate, because that is what we have now as far as anything new. In the next five years or so there are three rounds left in the chamber. Traits for three herbicide groups (dicamba, 2,4-D and the HPPD inhibitors) are being developed. Hard work is going into all of them. We need all three to be successful. It remains to be seen if they can be intercropped or grown together on the same farms or in the same areas. If not, we continue down the road of using up one technology at the time. There were presentations at the meeting on waterhemp resistance to 2,4-D and to the HPPD inhibitors and the technologies are not even here yet.
We continue failing to demonstrate that we can be smarter than weeds. There is no one answer. The answer is crop diversity, tillage diversity, herbicide diversity, trait diversity and soil seedbank management in every field starting now.