Farmers need more options to conquer herbicide resistant weeds


The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion and analysis.

There are two things that I think just about every weed scientist can agree on:

  1. herbicide resistant weeds make weed management more difficult; and
  2. the key to battling herbicide resistant weeds (or any weeds, really) is to use a diverse weed management program.

One aspect of a diverse weed management program is herbicide diversity. . . . But this leads to the question:

How diverse are US herbicide programs?

. . . .

. . . [T]he diversity data suggests that herbicide resistance traits (either through biotechnology or conventional breeding methods) can either increase or decrease herbicide diversity depending on how they are used. These data don’t support the claim that herbicide resistant crops, as a whole, have made the weed resistance problem worse (or better). . . .  Glyphosate seemed to supplement alternative herbicides in corn rather than replace them, as occurred in soybean. Presumably, those alternative soybean herbicides were still available, but they were not being used.

Herbicide resistant crops provide an additional tool for farmers to use. Whether or not that tool is used to effectively combat herbicide resistance or exacerbate the problem depends on many other factors. Economics, crop rotations, previous experiences, weed spectrum, etc. all play a major role in how farmers select and use herbicides. My guess is the reason other soybean (and cotton) herbicides didn’t see continued use after the introduction of glyphosate resistant varieties was that glyphosate was simply a much better herbicide. . . . If we’re serious about increasing herbicide diversity, then farmers need more effective tools, not less. But we need to do a better job of using them appropriately…

Again, it is important to remember that reliance on herbicides to solve herbicide resistance isn’t a winning proposition in the long-term. But increasing herbicide site of action diversity is generally agreed to be one important component for herbicide resistant weed management. If we agree that herbicide resistant weeds are a problem, and that we’d like to continue using herbicides for the foreseeable future, then the increased herbicide diversity observed in corn, rice, and wheat should probably be considered, on balance, a good thing.

Read full, original post: Herbicide Diversity Trends in US Crops, 1990-2014

  • Farmer with a Dell

    Hmmm. this article recites popular contemporary weed science concerns accurately enough. I agree we need a couple more unique herbicides and some intelligent strategies for rotating them to greatest long term effect. I am pleased to hear an agroecologist endorse this practical observation!

    Oh oh, I can’t help it…story time: We used to find value in paying some attention to controlling introduction and spread of weed seeds. I well remember diligently grubbing out hedgerows, clearing up rock piles and tiling overgrown sinkholes that harbored weeds and little else to commend them. We also exercised the most exquisite care to avoid buying hay with certain weeds and in harvesting our own feed crops before weeds could go to seed — if we failed, the next spring you could tell every pass the manure spreader had traveled the previous winter by the path of green weeds popping up across our fields. Dad and uncles were hell on combine operation in our beans and small grains to prevent tracking weed seeds from farm to farm, field to field. Not all custom combine crews could pass muster.

    I guess it’s been 20 years now since academics last concerned themselves with these basic realities…

    We first looked to controlling weed introduction and spread, making our herbicide strategies so much more effective. That’s what we meant back in the day when we talked about “clean farming” (so long ago and so obscure I cannot find an example on the internet to link here!)

    All the same, those fundamental concepts are of increasing importance as we install lavish permanent weedy buffer strips along every stream, marsh and mud puddle. We also are seeing more neighboring farms being left idle, or transitioned to organic management and part-time hobby operations where weeds are neglected, the seeds blowing onto our downwind fields and being tracked in by wildlife

    I would think “agroecologists” would be all over this systems concept of weed control. Now that agroecology claims credit for singlehandedly inventing crop rotation and cover crops, isn’t it about time to invent clean farming techniques for weed control? As long as wooden wheels are being re-invented, this is another good one to have in the quiver. Unless it clashes with a yuppie agenda somewhere or it simply isn’t sexy enough to make a proper soundbite.