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Custer’s Last Stand or Using Wipers or Mowers For Late-Season Weed Control in Peanut Fields (Prostko)

At some point, peanut growers must realize that it is futile to continue spraying herbicides over the top of their crop.  Either the weeds are too big and/or pre-harvest intervals cannot be followed.  In that case, there are 2 last resort weed control options for troublesome fields.  These include the use of either a non-selective applicator (i.e. wiper) or a flail mower.  Flail mowers (vertical blades) are preferred over rotary mowers (horizontal blades) because they uniformly distribute debris rather than dump it on one side of the mower (which can cause major digging problems).  The main goal with these weed control methods is to increase fungicide deposition and/or improve harvestability.  At this time of year, it is really way too late to recover any weed competition related yield losses.  Here are a few things to consider for both options.

1) A 33% or 50% solution of paraquat (depending upon formulation) is legal to apply in a non-selective applicator for the control of Palmer amaranth.  Check out page 223 in the 2021 UGA Pest Control Handbook for more specifics (tractor speed and weed heights are very important).  This treatment will also work well on Florida beggarweed and sicklepod.  No other herbicides are labeled for this type of application so don’t bother asking me about Liberty or dicamba (FYI, they don’t work well in these applicators either!!!).  I have tested several types of applicators over the years and prefer any of the ones pictured below. You can also check out the following slide set for more information about the research I have conducted on non-selective applicators (https://www.gaweed.com/slides/prostko-swss-2011/index.html).

2) I have used a flail mower to clean up my weedy test plots for many years.  I usually set the mower to remove about 2″-3″ of the peanut crop in addition to topping any weeds that are there.  Generally, 1 pass with the flail mower is OK but 2 passes are better (opposite directions). Check out these pictures from earlier today.

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