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HSMOC Adjuvants – More Questions (06/25/15)

HSMOC Adjuvants – More Questions

HSMOC Adjuvants – More Questions

Question #1: I got a call this morning from someone that insists on adding HSMOC with straight glyphosate. He said he gets greater weed efficacy even with glyphosate alone. Can you clarify?

Question #2: I have MSO questions for the dry bean micro mix. 1. Have you done research on which MSO’s work best with the bean mix. I was told Scoil used to be best, I don’t think it is made any more. 2. Should I be using the HSMOC with the bean mix or the regular MSO? Regular MSO is about $17/gal and HSMOC is about $27/gal. Thank you.

Question #3: We are having a debate about adjuvants for use in a specific tank-mix:

AMS + Glyphosate + Sharpen + HSMOC     OR     AMS + Glyphosate + Sharpen + MSO + NIS.

The crux of the issue, as usual, is cost. At 1 pint/acre the HSMOC cost would be $5.63/acre just for the HSMOC compared to MSO + NIS ≈ $2.75 (1 pt/acre) + $0.88 (0.25% @ 10 gpa) = $3.63/acre.

Some HSMOC labels do not show surfactant content but others show 25% surfactant so at 1 pt/A they would give an adequate surfactant load with a loaded glyphosate. We have an HSMOC in our warehouse and were going to use it with the above tank-mix in place of MSO. So, our questions are: Should we use a standard MSO + NIS and save the $2.00/acre? Or is the HSMOC worth the added cost to potentially not antagonize the glyphosate? Or could we simply add a little more glyphosate to overcome potential antagonism from the MSO? Sorry for the long winded e-mail over a $2.00/acre debate.

Answer: 

I suggest reading the section on HSMOC in the weed guide? - See page 70 in the e-file below:

http://www.ag.ndsu.edu/weeds/weed-control-guides/nd-weed-control-guide-1/wcg-files/a5-adjuvants

The amount of emulsifier (surfactant) in HSMOC is very important but what is equally or even more important is the quality of emulsifier in the HSMOC. The emulsifier can either be glyphosate friendly or unfriendly (antagonize glyphosate). The emulsifier’s in HSMOC adjuvants differ and even if you add surfactant to MSO to create your own HSMOC, it may still antagonize glyphosate activity. Perhaps you might get lucky and choose a good one but I don’t know which are good and which are bad with glyphosate. In addition to MSO having a low NIS content, they almost all have glyphosate unfriendly emulsifiers. I have taken many phone calls the last few days about cost of HSMOCs and ways to reduce the cost and maintain high herbicide activity. Everyone is looking for ways to reduce adjuvant cost and the answer is – marketing is your department – I just test for efficacy. Sorry.

Regarding adding more glyphosate to overcome the antagonism from oil adjuvants…..a great scientist (Dr. John Nalewaja) once said the following, “The best adjuvant for Roundup is more Roundup”. High glyphosate rates can overcome the antagonism from oil and can be considered to diminish the need for the more expensive HSMOC adjuvants.

Rich Zollinger

Extension Weed Specialist


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