More Mixing Comments

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Tank mixing questions:

I am beginning to get a lot of these relative to either postemergence herbicides or Apogee with fungicides. Take a look at 2015 Peanut Information for a general discussion. In all cases we have looked at fungicides do not impact broadleaf herbicides like Ultra blazer, Cobra, Basagran, Storm, Cadre, or 2,4-DB. Clorothalonil, Headline and Abound will affect grass control with clethodim. Crop injury from chlorothalonil has been observed when applied with crop oil concentrate, and adjuvant needed for most clethodim formulations and sethoxydim (Poast). I have not observed decreased grass control with Provost or Folicur.

There are some newer fungicides we have not looked at in terms of mixtures, but we plan to do some of that later this summer with Texas panicum. My recommendation has been to apply Apogee as a standalone treatment because of the crop oil concentrate and nitrogen that are needed for it to perform well. We did work a long time ago that showed that the combination of crop oil and nitrogen was better than nitrogen alone. The nitrogen is absolutely critical and crop oil concentrate alone is inadequate. When mixing with other products we have never seen less row visibility. It has certainly been years since we did that work, with Headline the last new fungicide we looked at in any detail. We may get back to some of these this year. The concern has often been the crop oil and how it affects fungicide deposition. Products that are needed at the base of the plant or on limbs for stem rot and sclerotinia blight might be compromised with crop oil or nitrogen and the combination of these. If you always leave in the nitrogen and leave off the crop oil you will get good performance but there will be times when the combination will work better. I suspect the nitrogen will have less impact on fungicide deposition that the nitrogen. But again, Apogee is expensive and I would want it to perform well for the money. Also have people look closely at the label for gallons per acre and adjuvant suggestions. They should go by that. In all of our work adding a pyrethroid has not had an impact on weed control or Apogee performance. We have not looked at Steward.

Manganese is compatible with many herbicides other than 2,4-DB and we have not observed reductions in performance of either component when mixed. Boron is compatible with most pesticides I am aware of. Don’t mix boron and manganese. The adjuvant can affect absorption of boron and sometimes I have been concerned about increased injury from elevated boron if the mixture has surfactant or crop oil in it. I would apply manganese only if I saw symptoms (although 75% of growers make a routine application) and I would apply boron in all cases. These tag along nicely with fungicides.

I’ll send more comments as time goes by.

Article first appeared as North Carolina Peanut Note (PNNC-2015-081)

Written By

Dr. David JordanExtension Peanut Specialist (919) 515-4068 david_jordan@ncsu.eduCrop and Soil Sciences - NC State University
Updated on Feb 23, 2016
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