Results of the 2016 Weed Science Society of America weed survey for broadleaf crops, fruits and vegetables are in. Across all crops, Palmer amaranth was the most troublesome and difficult to control weed, and lambsquarters was most common. In soybeans, however, marestail and waterhemp were the most difficult to control, and waterhemp was the most common. All of these weeds except lambsquarters are difficult to manage in soybeans for a combination of reasons – complex biology, prolific seed production, extended periods of emergence, and a tendency to develop resistance to multiple herbicide sites of action. So if you’re still struggling with marestail (aren’t we all), you’re not alone. If you’re still struggling with lambsquarters in soybeans, we extend no sympathy here – take two residual herbicides and call us in the morning.
Reminders about some recent videos we made, etc. First, corn replanting is in full swing in areas due to the effect of previous cold and wet weather on stands. It’s important to kill the first stand of corn to make room for the second. If not removed, plants from the first stand essentially act as weeds in the second planting. Research we conducted with Purdue in 2009-10 showed that yield of the second planting was maximized most consistently when it developed in the absence of plants leftover from the first stand. The following video summarizes methods of killing the first stand.
We also made a follow up video on control of larger marestail with burndown herbicides. In this one, we walked through our research plots a couple weeks after most of the burndown treatments were applied, and reviewed effectiveness of the herbicide combinations we listed in the first video (which can be found in May 5 blog post below).
And finally, in the category of “not everything goes the way it was planned”, we have a few photos from our spray day at OARDC Western Ag Research Station last Friday. We planted all of our soybean plots last Wednesday, and needed to get the preemergence herbicides on as soon as possible to ensure they received a timely rain. Well it was too windy to spray the next two days and then the station received two inches of rain late Thursday, turning the place into mud. Knowing that there was more rain coming, we opted to go ahead and wade through the mud to get the plots sprayed. Had to wait for water to drain on some of it. Not ideal for sure but the use of backpacks and handheld booms allowed us to go where it would have been impossible for anything motorized to go. Stuff happens.
The warm winter and early spring resulted in some awesome weed growth in no-till fields, and larger than normal marestail for this time of the year. And the current spell of wet, windy weather is preventing field operations. This can create some significant challenges for burndown programs in fields not treated with herbicides last fall. Check out the video for some advice on modifying burndown programs to better handle large marestail. As always, contact us if you have questions.
The photos of marestail here were taken in front of my house, along the intersection of the driveway and front walkway. I have to suspect, given the proximity of these plants to where I exit the car every day, it’s likely that the marestail seed traveled with me from the OARDC Western Ag Research Station of another crop field. I have found marestail all over Columbus, though, and there is plenty along the Scioto River which is just to the west of me. So there is the possibility of seed traveling with prevailing weeds up the hill from the river. So far the marestail around the house have been resistant to glyphosate, and my solution has been hand weeding and glufosinate (this allowed me to learn also that a high rate of glufosinate will kill lawn grasses). One would think that resistance to glyphosate indicates the the seed came from an agricultural field rather than a native area, parkland, etc. Recent work by a graduate student here at OSU compared the frequency of glyphosate resistance in marestail populations from north central Ohio with those from southern Iowa, and also compared populations from agricultural versus non-agricultural sites. All of the populations from Ohio agricultural sites exhibited high level resistance, along with 60% of the populations from non-agricultural sites. While over 90% of the Iowa populations from agricultural sites were resistant to glyphosate, the number with low versus high levels of resistance was fairly even. And while 45% of the Iowa populations from non-agricultural sites were resistant to glyphosate, this occurred only at the lowest level of resistance for the majority. In the end there can be plenty of glyphosate use and selection for resistance in both agricultural and non-agricultural areas, depending upon how they are managed. Here in Ohio, it’s likely that a new infestation of marestail will be highly resistant to glyphosate, regardless of the seed source. I suppose that cleaning my clothes and shoes well after working in marestail-infested areas could have prevented these plants in my driveway. But I might have also needed a fine-meshed net on the west side of the house to prevent the influx of windborne seed. Just some of the reasons why marestail remains enemy number one in soybeans.
The world recently lost Judge Joseph Wapner, a man of integrity who brought evenhandedness and a gentle humor to the proceedings of The People’s Court. Along with judicial wisdom, he could have low tolerance for the many idiots who came through his court, and always found a way to bore right to the core issues. He probably would have had low tolerance for the recent dealings we had with two agrichemical giants over an herbicide ad one of them apparently ran in parts of Illinois. For the sake of anonymity, we can call these two giants, “large company S” and “large company D”. Both companies sell very broad spectrum, multi-component preemergence corn herbicide premix products, and of course both “large company S” and “large company D” believe their products walk on water and are truly superior to all other preemergence corn products. The ad in question, produced by “large company S”, showed combined yield results from a 2016 study conducted by OSU and Purdue that compared weed control and yield from various premergence corn herbicides. As shown in the ad bar chart and wording, the product of “large company S” resulted in a “yield advantage” compared with use of the “large company D” product. “Large company D” asked us to review the ad for accuracy. Upon reviewing the data from the two individual OSU and Purdue studies, we found that there was no significant difference in yield between the two products that walk on water in either study. Nonetheless, someone at “large company S” HQ decided to average yields between studies and create an ad that made it look as though there was higher yield for their product. We do have to respect the ability of “large company S” to fess up when we confronted them with this. Their response was essentially “yup you caught us. We ignored the statistics and just floated it out there anyway figuring that no one would notice”.
In the meantime, it was pointed out to us that while trying to occupy most of the high moral ground here, “large company D” was known to be cutting recommended rates of their product that walks on water in certain areas to be more cost competitive with the “large company S” product. And in the end “large company S” essentially reminded us of the possibly also somewhat dubious approach of “large company D” in selling product and stated “the attorneys for large company D can contact our attorneys if they want to pursue this further”. We believe in the legal world these are known as the “wait – but they did this” and “nananana poo poo – just try to get us” arguments. Both very effective at times we’re sure. However we can’t help thinking that in this case even Judge Wapner’s response might have been, “Bailiff, kick these people in the a** and get them out of my court”. (In the interest of honesty, which is what this blog post is about, we should say we borrowed this last quote from a Doonesbury comic strip. Always wanted to use this somewhere.)
We have been doing this for 25+ years, and have observed numerous instances where companies manipulated data somewhat or ignored statistics to create the story they want. This manipulation can be the only reason why herbicide ads for a given product always show that product as either more effective or providing higher yield than the competitors’ products. In all fairness to companies, it probably doesn’t make much sense to run an ad that shows the opposite. In fact, we had this same discussion with “large company S” a couple of years ago, with regard to another of their ads. The ad also showed a bar chart where their preemergence corn product that walks on water outyielded the competitors’ products in an OSU trial. Checking our data, it was apparent that there was no significant yield difference, but you never would have known this from the ad, where the bar for their product was a different color and substantially taller than the other bars. Because different colors of course do indicate that significant differences occurred regardless of what the statistics showed. Which leads us to ask “large company S” (and everyone else really), if you’re going to ignore the statistics that in fact show whether real differences occurred, why even bother to have independent researchers such as OSU and Purdue conduct the study? Why not just make up the results so that everyone knows your product is truly the best?
We really have better things to do than try to police ads where our data are misrepresented. It’s not a very rewarding activity. We don’t want to say it’s a mistake to ever trust the yield results shown in herbicide ads – no wait – let’s go with that – it’s a mistake to ever trust yield results shown in herbicide ads. And hey – just a reminder – experimental design and statistical analysis procedures exist for a reason. If we ignore them, then all we’re left with are “alternative facts”, right?
It’s a brutally competitive herbicide sales world out there. Stay ethical my friends. RIP Your Honor.
Labels for XtendiMax (Monsanto), Fexapan (DuPont), and Engenia (BASF) are available online at CDMS and other label sites. Fexapan is the same formulation and label as XtendiMax. They are provided here also in case it’s helpful. For each product there is a main label and then also a supplemental label with directions specific to soybeans. Both labels should be reviewed by applicators, especially with regard to stewardship to prevent off-target movement. The soybean label alone does not provide all of the necessary information on this. Below the links to labels are links to: 1) an OSU Powerpoint pdf that summarizes some of the label information; and 2) a new USB Take Action infographic on spray drift prevention. Any other product of any kind that will be mixed with XtendiMax, Fexapan, or Engenia must be approved and listed at the corresponding websites, along with any nozzles used for application.
It’s been a “fun” couple weeks to be a weed scientist. While on vacation we were getting calls about new Palmer amaranth finds and had to make the recommendation to mow down one field of soybeans in SW Ohio to prevent an even bigger mess next year. Another field in that same area had enough plants to justify localized mowing where the plants were. The initial introduction of Palmer appeared to be due to purchase of a combine from Georgia, which was used in several operations. Early this week we visited several soybean fields in NE Ohio that had also been mowed down due to dense Palmer infestations after an OSU county educator talked to the growers. A couple more fields nearby probably should have been mowed down as well. Photos of some of the mowed and unmowed fields below. A central thing about Palmer amaranth has been reinforced through all of this. The message that we got from our counterparts in the south several years ago when Palmer started to rear it’s ugly head here was – “you have to get across to growers that if seed production is not stopped when there are just a few plants, this weed will take over a field faster than any other weed they have dealt with.” This is due to the extremely prolific seed production that can be well upwards of 200,000 seeds per plant. And this was readily apparent for the fields that had to be mowed down. We know that Palmer was in these fields last year, but apparently not at a level to raise concern. And this year it’s essentially game over. Be warned. It’s also apparent that mowing of large plants with seedheads will usually have to be followed with some type of aggressive tillage that cuts up plants well so that they cannot recover and still produce seed. We also observed plenty of new Palmer plants emerging still, and this season-long emergence is another trait that makes it so tough to manage.