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Senior Advisor

Fall Spraying ?

First off --- Heres a copy and paste out of Penn State on fall spraying .


Does Fall Horseweed/Marestail Management Make Sense?

Posted: September 17, 2013

Fall herbicide treatments are an important component of marestail management programs.

Horseweed or marestail has finally reached western Pennsylvania.  We even had a report of a problem in soybeans in the northern tier which borders NY State.  Fall herbicide application for horseweed management is one option.  Dr. Mark Loux at Ohio State ( has written a number of articles about horseweed control and fall herbicide applications.  This is a summary of the main points:

  • Fall herbicide treatments are an important component of marestail management programs, although fall is not where the majority of the money should be spent on managing this weed.
  • The primary role of the fall treatment is to remove the marestail plants that emerge in late summer and fall, so that the spring herbicide treatments do not have to control plants that have overwintered and are potentially larger and more mature.
  • A field that is fairly weed-free following corn or soybean harvest may not require fall treatment. 
  • Fall treatments have been fairly consistent when applied up until December in Ohio.

 The core fall herbicide treatments include:

  • Glyphosate + 2,4-D (0.38 to 0.75 lb + 0.5 lb ae/A)   -  can be used in the fall prior to any spring crop and can even allow for establishment of a fall cereal/cover crop if desired.
  • 2,4-D + dicamba (0.25 to 0.5 lb ae/A each) – can be used in the fall prior to corn or soybean and can also allow for establishment of a fall cereal/cover crop if desired.
  • Metribuzin + 2,4-D -  can be used prior to corn or soybean.  The metribuzin can provide some residual weed control into late fall, but usually not spring
  • Canopy EX or DF (chlorimuron) + 2,4-D – can be used prior to soybean.  A fairly low rate (1 oz EX or 2 oz DF) works well, but a higher rate may be necessary for longer residual.   This is the only residual herbicide that provides substantial residual control into the spring and only for weeds that are not ALS-resistant. 
  • Basis or Simazine + 2,4-D – Both can be used prior to corn.  Basis or Simazine provide residual control of winter annual weeds into late fall/early spring.
  • Other fall treatments that include Autumn, Express, etc. with glyphosate and/or 2,4-D are also possible but they tend to be less effective than Basis or Canopy treatments on some weeds including dandelion.  Other residual herbicides such as Valor, FirstRate, etc. seem better suited for spring rather than fall application.

Contact Information

  • Professor of Weed Science
Phone: 814-863-1014
  • Program Development Specialist
Phone: 814-865-2242
Second --I  have been playing with this for 4 years now - the first year and second was just rying to find out what worked for me . the last 2 years it's been spray all acres in the fall -
The First year was only 1 QT. of 2-4- D -- The fert. companies all said -- Ken your wasting your time - there is NO residual in the 2-4 D - to my reply -  said then WHY do you say that I haveto wait a month in the  spring to plant - at the QT rate IF theres NO residual -- they just looked at me then started to laugh - well they said - you have a point - lol
Second year - I added Power max . Then the last 2 years I have used a product called weedmaster ( 2 modes of action of Dicamba with 22  oz.s of Power Max.
I have had good luck with this to help controll marestail - I have a neighbor that ues Basis Blend with Distinct -- and I will say it looks very , very good .
Just wondering if you guys are useing anything different that works good .
Have a good one
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5 Replies

Re: Fall Spraying ?

i used what the co-op called autumn-don't know what's in it but it worked great. sprayed in november and fields were clean until last of may when we finally got into the field

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Senior Contributor

Re: Fall Spraying ?

Have used canopy for the past 6 years, with good results. I tried valor on couple hundred acres in fall of
2010 but had break threw of marestail, went back to 100% canopy, fields usually clean of every thing till the first of May.
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Senior Advisor

Re: Fall Spraying ?

Call me old fashioned, but I have had good luck using 1# to 1-1/2# atrazine with 24oz. 6# Gly., 8oz. LV6 and 4oz. Dicamba on all acres going into corn or milo.  If I was planning soybeans, I would substitute Valor for the atrazine.  Generally applied in early to mid Nov. after all milo has been harvested.  If we receive adequate late fall or winter moisture to activate the atrazine, you can definitely tell in the spring which acres were sprayed and which ones weren't.


Trying something new this year on my winter wheat residual herbicide, instead of coming over the top in late Nov. or early Dec., I am tank mixing them with my corn stubble burndown chemicals to see if a 1 pass approach is effective.  Always something new here in the "New Indiana".

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Senior Contributor

Re: Fall Spraying ?

I use Jack Frost and 518 of invert. Works great for controlling weeds for me!
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Veteran Contributor

Re: Fall Spraying ?

Fall spraying, cover crops, tillage radishes...makes me glad we have a short growing season, four feet of frost, and 10 feet of snow. 🙂  

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