All posts by Larry Steckel, Extension Weed Specialist

Early-Season Weed Concerns in ThyrvOn Cotton

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Picture 1. Palmer amaranth and goosegrass that emerged at 1 to 2 lf cotton and then escaped Post Application of Engenia + Glyphosate fb/Liberty + Glyphosate. Picture August 2022. Madison County TN

My understanding is that some cotton planted this year will contain the ThryvOn trait.   According to UT entomologist Sebe Brown these varieties will likely not require any POST foliar insecticide application for thrips.  This is great as far as management for that pest but from a weed management perspective this could be a problem. Continue reading


Mitigating Potential Herbicide Mixing Issues

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This time of year as we move to burndown behind the planter we typically get some reports of mixing issues when either glyphosate or Gramoxone is added to the tank with residual herbicides like atrazine, metribuzin, Cotoran, Caparol, fomesafen or a pyroxasulfone containing product.  What happens is the white herbicides will often clabber up and stop up screens and strainers in the sprayer. Continue reading


Thinking ahead: Vine Control in Corn

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2022: Burcucumber growing over top of mature corn

Practically every September some growers are dismayed at the vine infestations present at corn harvest.  Often, these weed infestations emerged after PRE applied or early POST applied herbicides had played out.  They grew very little until August and as the corn dried down and light became more available those established weeds started rapidly growing. Continue reading


Ryegrass Management in Corn

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There were a number of reports of ryegrass escaping burndown in fields that either will soon be planted to corn or just had been planted to corn.  Thankfully this issue seems less of a problem than a year ago.  In most cases the ryegrass escaped glyphosate + dicamba early burndown.  Paraquat application has the best probability of controlling ryegrass that has escaped early burndown. Continue reading


Application Time of Day Affects Gramoxone Performance on Some Weeds

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With the planting season started, many people are thinking about using Gramoxone (paraquat) as a burndown for many weeds present at planting.  Gramoxone is a very good broad-spectrum herbicide that has been the go to for burndown of many winter and summer annual broadleaf weeds. With Palmer amaranth starting to emerge, Gramoxone is the only sure thing that will control it. However, it is less consistent controlling some weeds like horseweed (marestail). Continue reading


Early Burndown Results

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Picture 1. Left Untreated – Right 40 ozs Roundup Power Max 3 Applied March 17, 2023

We have had the opportunity to observe field and demo burndowns around West Tennessee.  In general, going back “old school” and applying glyphosate alone provided very effective burndown.  This includes applications made back in mid-March when night time temperatures were below freezing (Picture 1). Continue reading


Importance of Using Effective Residual Herbicides in Soybean and Cotton

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2022 Palmer amaranth escape Engenia + glyphoste PRE/ followed by Engenia + Glyphosate applied POST. (Picture 1)

Increase in input costs and lower relative commodity prices compared to last year may tempt some to forgo using a PRE this spring.  Since glyphosate and dicamba have actually gone down in price, it may be tempting to try this combination near planting, then hope that dicamba will provide enough residual weed control to hold until those herbicides can be applied again early POST.   Continue reading


Cover Crop Burndown Time

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Good soybean stand in cover crop cereal rye

It is cover crop burndown time. There is no one size fits all recommendation for cover crop control.  It really depends on the environment and the cover crop species in the field.  With respect to environment, cover crop burndown can be tricky during periods of long stretches of saturated soil conditions. This is particularly true with systemic herbicides where translocation of those herbicides to growing points can become limited. Continue reading