All posts by Larry Steckel, Extension Weed Specialist

Glyphosate-Resistant Johnsongrass Management

Johnsongrass Escaping Glyphosate Burndown

Large patches of Johnsongrass that have gotten through glyphosate burndown are now very prevalent in many fields. This is particularly noticeable in several southeastern counties of West Tennessee where some of the Johnsongrass has shaken off burndown and now is almost waist high in some cases. The main threat with Johnsongrass is in corn where there are few POST applied options. Continue reading


Ryegrass Weed Control in April

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Picture 1. Roundup PM 32 ozs/A 21 days after application

A good many reports from the field reflect what our research this spring has shown.  In short, clethodim is the herbicide of choice to control ryegrass.  Often clethodim tankmixed with glyphosate can improve the probability of better overall control.  Ryegrass control with glyphosate alone is much more hit and miss both in our research and in many fields this year (Picture 1). Continue reading


Cover Crop Burndown

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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 rain predicted over the next few days, one should be mindful that cover crop burndown can be tricky during periods of saturated soil conditions. This is particularly true with systemic herbicides where translocation of those herbicides to growing points can become limited. Continue reading


Ryegrass Burndown

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Corn in a ryegrass field

Ryegrass was a major issue last spring. For managing GR ryegrass, it is best to do it as early as practical and utilize a clethodim + glyphosate tankmix. This tankmix needs to be applied at least 30 days ahead of corn planting to use a clethodim rate that has any chance of controlling well established ryegrass. Continue reading


Lily Weed Family Burndown

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Blue flowers distinguish grape hyacinth from wild garlic

There have been questions on control of wild garlic, grape hyacinth and in a few cases, star-of-Bethlehem. These three weeds, in the Lily family, are often mistaken for each other as they all derive from bulbs and are low-growing perennials. Continue reading


Multiple-Herbicide Resistant Waterhemp in Tennessee

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Waterhemp that escaped multiple applications of Engenia + Glyphosate

Last year we reported on waterhemp in Montgomery and Macon counties that was resistant to dicamba.  We came to this conclusion from both research we conducted in the fields and the confirmation of those results by greenhouse research. The greenhouse research was conducted at Purdue University by my colleague Dr. Bill Johnson and his graduate student Claudia Bland. Continue reading


Fall Application Ryegrass Control

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Corn in a ryegrass field

Ryegrass has become a serous weed issue in some fields that past couple of years.  A major reason for this is that much of it is now glyphosate-resistant.  Even if clethodim is used rather than glyphosate often it is applied on ryegrass sometime in late March through April when the grass is too well established to provide consistent control. Continue reading