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
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
Last spring a good many folks went back “old school” and applied glyphosate alone for burndown and saw very good results. This includes applications made when nighttime temperatures were below freezing (Picture 1).
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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
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
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
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
Driving across West Tennessee last week it is very apparent we have taken a step backward on Palmer amaranth control. Many fields that looked clean from the road in late July are now showing large Palmer amaranth escapes. Upon closer inspection the pigweed escapes are at least partially affected by the dicamba applications which resulted in them staying hidden from the road until the last couple of weeks. Continue reading