All posts by Larry Steckel, Extension Weed Specialist

Management of Large Horseweed in Soybean

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Horsweed recovering from 0.5 lb of dicamba

There have been a few reports of good sized (>12”) horseweed (marestail) putting on significant new growth after an Engenia or Xtendimax application. Though these occurrences have been relatively few they are a concern as the horseweed appears to be growing back with a vengeance (Picture right).

As we go into the double crop soybean planting stretch these reports are a good reminder to apply a good burndown on horseweed prior to even Xtend soybeans emerging. Continue reading


Final Verdict on First Field with Reported Poor Palmer Amaranth Control with Dicamba

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I blogged several weeks back on the poor Palmer amaranth control with Engenia in a field in Fayette County.  We followed up by applying another application of Engenia on the still green Palmer 14 days after the first application.   I am glad to report that all the Palmer amaranth were controlled 14 days after the second Engenia application. Continue reading


Will the Palmer Amaranth Die after an Engenia or Xtendimax Application???

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The question of the week is will the Palmer amaranth die that is still green after an Engenia or Xtendimax application? The situation is that many pigweeds in some fields have not grown after an Engenia or Xtendimax application but still remain green going on 10 days or more after the application.  The question is will these pigweeds start to regrow? Continue reading


Scout Cotton Fields for Palmer Amaranth Breaking Through Residual Control

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The very wet May has led to rapid degradation of the PRE applied herbicides in cotton.  In our tests at Jackson that were planted 21 days ago all the PRE applied herbicides have broken.  Some broke very quickly after application while others held on a little better, even with all the rain. Continue reading


Follow Up Questions on Reports of Poor Palmer Amaranth Control with Dicamba

The blog on inconsistent dicamba performance on Palmer amaranth has caused some follow up questions.

Is there any difference between Engenia, Xtendimax and Clarity for actual Palmer amaranth control? NO. I know from repeated research with all three that they all perform fairly well on a 1 to 4” Palmer amaranth.  They all often need follow up applications on Palmer that is larger than 4”.

Are PRE applied herbicides needed in Xtend soybeans?  YES. The folks to date who have had issues with dicamba performance were not using any PRE applied herbicides. It is hard to get good coverage in those thick mats of pigweeds where PREs have not been used.