Renewable Farming

Updates from a crop consultant on control of resistant weeds for the 2017 season

Last week was important for anyone who wanted to gather as much ag knowledge as possible. There was an ag consultants’ late-fall tech seminar in Ames, the big ISU Extension-sponsored ICM Conference was held on Nov. 30 and Dec. 1 on the campus, and the national ACRES U.S.A. EcoAg Conference was held in Omaha. 

Dec. 9, 2016  By Bob Streit — At the consultants’ meeting we got to listen to a number of presenters give us their company’s rundowns on what new herbicide tank mix or mixes they were going to be introducing and selling this next season.

Most of the talks repeated the mantra that were very few brand new products. Instead it was mostly a litany of what new combinations the major companies had assembled and were hoping to market in the coming year. The one actual new product as a new fungicide family contained in the Thrivent product from Syngenta.

It apparently lasts much longer than the Strobe or Triazole products.

In the area of weed control, the major theme was that the use of residuals herbicides was expected to be increased even more this year. The common recommendation was going to apply them sequentially during the season so there would be no herbicide gap that any weed species was going to exploit by having a new batch of seeds germinate and emerge while people were not paying attention.

I never thought I would hear this spoken: One of the reps mentioned that in their company’s greenhouse, they were trying to develop 2,4-D and Banvel tolerant weeds — and they were able to in three generations.

The takehome message was this: Expect strong selective pressure and enough heterozygosity in many weed populations to help force resistant genotypes.

Use overlapping residual herbicides, and in the case of Palmer, try not to let it germinate.

At the upcoming Dec 13 meeting in Ames, sponsored by SprayTech, one of the guest speakers will be Dr. James Norsworthy, an Extension plant scientist from Arkansas. He is well acquainted with Palmer and will provide advice on how to manage for it. Another speaker will be a noted plant pathologist/physiologist now retired from Purdue. We will also get to listen to Sue Martin and her marketing advice.

At that conference we will also get educated at their new mineral-based spray products that fill dual roles in controlling weeds and diseases. If this sounds interesting there still be room for a few more attendees.

Call Carol at (515) 231-6710 to see if any room at the Gateway in Ames is still available.


One topic from the IICCA discussion was about plant safteners, how they work and their value. While they have been used in crops for several years not many growers know much about them and how they function.

The first modern one was called 1,6 Napthalic hydroxide. It came from a company in Manheim, Germany and protected plants against most ALS herbicides. This included Scepter and Pursuit and it worked miraculously well.

However, there were differences in performance between the German- and Chinese-made products so it never got commercialized. Some got bottled as F-80. It worked by increasing the activity of the P-450 system.

Scepter eliminated the formation of three amino acids, so F-80 restored their production within the plants. Interestingly enough that same product was also used in the paint industry to coat metals before powdered paint dust was applied and baked on machinery.

Now we see Bayer’s safteners, which had root in the old Rhone Poulenc company’s library, widely used in several companies’ herbicides. DiFlexx, Status, Balance Flex, Rimsulfuron-based herbicides and Corvus are those that use them. One of them can be applied to the soil and foliarly and one only foliarly.

This allows their use on susceptible germplasm, of which there are several families that are more susceptible than average to ALS chemistry.

One of the big admonitions from the different reps was to always read the labels to see what is and is not an allowed application.

The big ISU Extension Conference, the Acres EcoAg Conference, and the two-day Farm News Ag Show in Fort Dodge were held last week with good crowds at all. I will discuss them more next week.  Stay warm in the meantime.

Bob Streit is an independent crop consultant. He can be reached at (515) 709-0143 or