Great Bend Tribune
Published August 6, 2017
Today’s column is in the form of a two-part story. Hopefully it will demonstrate the danger in not thinking long-term and trying to identify the unintended consequences when making farming decisions. Before we start, the goal here is not to identify villains, or heroes for that matter, but the need for everyone involved in agriculture to try and think in the very long-term and critically evaluate information. And for those of us past a certain age, this is the Readers’ Digest version.
By the late 1980s broadleaf weeds were developing resistance to the herbicide chemistries used to control them in soybean fields. Companies like Monsanto and DuPont were working on a solution. Both came up with a solution at approximately the same time. Monsanto through the magic of genetic engineering developed Roundup Ready ® technology that allowed this nonselective herbicide to spray over soybeans without harming, provided you followed directions, or killing them. Glyphosate, the active ingredient in Roundup, completely controlled not only troublesome broadleaf weeds in the soybean crop but also most grasses. And Monsanto promoted this as a way to eliminate pre-plant/emergence spraying with more expensive chemistries. To further help producers decide, Monsanto also dramatically slashed the price of Roundup.
DuPont developed STS technology to address the same issue at the same time. STS stands for sulfonylurea tolerant soybeans. This was a different mode of action from Roundup and involved several herbicides that were particularly effective at control but also at damaging/killing soybean plants and STS technology overcame that problem. An additional advantage was that these chemistries had residual activity while Roundup didn’t. They also looked at soybeans that were both Roundup and STS tolerant but didn’t release them then. They didn’t dramatically cut the price of their products nor did they promote it as being able to eliminate pre herbicide programs. They didn’t emphasize cheap control as much as good, sustained control.
Weed control scientists and extension specialists in the corn and soybean growing regions of the country weighed in with concerns. They stressed the need for pre-emergence herbicides for early season control. They had other concerns, especially the need to rotate modes of action (what kills the weed) but here was their major fear. Roundup had been around for almost twenty years by then and was used to control weeds in place of tillage. For example, Kansas wheat farmers used huge quantities of it for fallow weed control to conserve soil moisture. One of the benefits of rotating crops between grasses and broadleaves was you rotated herbicide mode of action. The mantra was to really control your grasses in the broadleaf crop and the broadleaf weeds in your grass crop. They liked what this technology did but that it needed to be used as part of an integrated herbicide program, not as a standalone. Based upon what had happened with early herbicides for corn and soybeans, they were afraid the overreliance on a single mode of action would create herbicide resistance in problem weeds that were already resistant to other herbicides.
As you probably know, cheap and easy Roundup won the day. It was not only cheap but it worked great after a few bugs were worked out and as the technology allowed for spraying over a longer time window. DuPont’s STS technology, which worked as good as or better than Monsanto’s didn’t fare well and within a few years Roundup Ready ® soybeans ruled the market. Next week: what happened and most of us don’t really know the whole story.
Published August 13, 2017
Today’s column finishes a two-part story regarding Roundup Ready® technology and the unintended consequences of long-term vs. short-term thinking. Remember Roundup Ready® soybeans crushed the DuPont STS competition. With the success of soybeans, Roundup Ready® corn soon followed and grew in acreage as did cotton, canola, alfalfa, and sugar beets. This initially worked well, saved farmers money on herbicides and allowed for decreased tillage. During this time other herbicide chemistries and seed technologies were being developed but except in wheat and later sorghum, crops without Roundup Ready® technology, had a hard time finding a market. Than what was a concern with weed scientists as discussed last week, weed resistance to glyphosate, started to rear its head.
At first there were just some reports that higher rates were needed or weeds were taking longer to die, and so on. The weed scientists started taking a look and through lab tests tried to determine what was going on, especially with pigweed. K-State weed scientists applied rates many times the labelled rate under controlled settings and found the pigweed wouldn’t die. Similar findings arose across the country. There were other factors in declining weed control such as improper application and low rates but the number of glyphosate resistant weeds was increasing rapidly. An international survey of glyphosate herbicide resist weeds indicates over 270 species as of 2016. The short term benefit, just as many weed scientists had warned was gone. What were the results?
- Minimizing or eliminating tillage for weed control became more difficult and many who had eliminated tillage started using tillage for weed control again.
- More expensive herbicides were available and their use increased. But in many cases, there weren’t good alternatives available or the control was incomplete.
- Producers are having to make more trips over the field to control problem weeds with different herbicides, tillage or a combination of both.
- Remember those STS soybeans DuPont developed that were outcompeted by Monsanto’s technology. They made a comeback and were even combined with the Roundup Ready® technology.
- Weed control of problem weeds has become more problematic and where these resistant weeds are present, decreased crop yield and quality. In certain cases, crop sequences have to be changed to deal with resistant weeds or extended fallow periods are used for weed control.
- Manufacturers of many older herbicides, including pre-emergent herbicides are seeing an increase in sales. Many of these while effective, are much more expensive.
- New technologies such as dicamba and 2, 4-D tolerant soybeans were developed for broadleaf control in soybeans.
This doesn’t mean glyphosate (Roundup) is still a valuable tool or the issue can’t be addressed but it will require added expenses, time, and increased management. The frustrating part for all concerned was that issue could have been avoided and we knew how. Next week’s column will discuss dicamba tolerant soybeans and the challenge they present.