Recent Updates

Crunch Time for Weed Control

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Picture 1. Goosegrass escaping multiple glyphosate applications. Tipton County. Mid-June 2022

As the calendar turns to June weed management concerns change from ryegrass and horseweed to the summer annuals goosegrass, junglerice and Palmer amaranth.

Tennessee growers are in a real crunch time to control these three summer annual weeds. Big percentages of the corn, soybean and cotton crops all need some kind of POST application right now. The planter technology that can plant three different crops across large acreages very quickly has one drawback. The sprayers often cannot keep up to most every acre needing to be sprayed just as quickly. Continue reading


Herbicide Stewardship

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It is crunch time for weed control in our row crops.  When every minute counts to get herbicide applied it is tempting to cut corners on herbicide stewardship.  The forecast would suggest that Tennessee will be entering a bit of a dry spell.  Herbicide drift is even harder for crops to recover from when drought stressed so please take time to use best management practices applying all herbicides but particularly products that contain dicamba and 2,4-D. Continue reading


Yield potential by planting date, managing for earliness

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Although many in the state have finished planting, several are touching up wet spots or the occasional drowned out field.  Unfortunately, others have seemed to catch two-fold the rainfall of the rest of the state and still have a large amount of ground to cover before they’ll near completion. In this article, I briefly discuss several important factors to consider during the replant or late plant scenario and provide a little data on yield potential by plant date. Continue reading


Corn Herbicide Maturity Cut-Offs

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How large can corn be before glyphosate could potentially cause injury? The glyphosate label states it can be applied up through the V8 corn growth stage. My experience has been if glyphosate is applied to corn larger than that it can at times cause ears to be barren.  This phenomenon is difficult to predict ahead of time as it can vary due to maturity of the corn at application, hybrid and weather.

Crop stage and/or crop height is used to determine the cutoffs for a given herbicide.  Often the label states the limits at whichever (crop stage or crop height) comes first.  Crop stage can easily be done by counting the number of leaf collars that are fully exposed (ex.  4 collars = 4 leaf) (Picture below).

4 leaf (collar) corn – V4 stage

Postemergence Corn Herbicides Crop Height Cutoff Crop Stage Cutoff
Accent 20 inches 6 leaf
Atrazine (Bicep, Degree Xtra, Acuron, etc.) 12 inches
Buctril 8 leaf
Callisto* 30 inches (without atrazine)
Capreno* 20 inches 7 leaf (without atrazine)
Corvus 2 leaf
Dicamba (Banvel, Clarity) 8 inches (1 pt/A) or
36 inches (1/2 pt/A)
5 leaf

Distinct 24 inches
Glyphosate – RR corn only 30 inches 8 leaf
Halex GT 30 inches 8 leaf
Hornet 24 inches
Armezon/Impact 8 leaf
Laudis 8 leaf
Liberty (Ignite) – LL corn only 24 inches 7 leaf
Diflexx 36 inches 6 leaf
Realm Q 20 inches 7 leaf
Resource 10 leaf
Resolve Q 20 inches 7 leaf
Roundup PM – RR corn only 8 leaf
Status 36 inches 10 leaf
Steadfast Q 20 inches 7 leaf
2,4-D 8 inches

*Note that if atrazine is added to herbicides such as Callisto or Capreno for example, the cutoff would be reduced to 12 inches.


Corn and Soybean Tolerance to Flooding and Submergence

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Excessive rainfall over the weekend (5/12 and 5/13) in the North Western river counties has resulted in several calls this week concerning flooding and standing water in corn and to a lesser extent in soybean. Crop response will depend on the length of time the crop remains submerged and varies between corn and soybean. With rain still in the forecast for the next few days, here are a few agronomic considerations to be aware of. Continue reading


Ryegrass Issues Persist and Johnsongrass Management

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Ryegrass Infestation in Corn

Ryegrass infestations still persist in some fields.  In cotton and soybeans, clethodim can be used now to push this weed on to maturity. In corn, other than just going out and spraying the typical POST corn premix and hoping that pushes the ryegrass on to maturity there is no real solution to controlling it. Continue reading


Nutrient Deficiency – Nitrogen

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This is the first of several installments dealing with commonly observed nutrient deficiencies in corn and soybean.  Each week, a new macro or micro nutrient will be posted and discussed. The main objective of this series will be to discuss for each nutrient: (1) visual symptomology of deficiency, (2) plant and leaf tissue deficiency levels, (3) common causes of deficiency, and (4) in-season corrective measures. Continue reading