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
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.
The vines in question are often perennial in growth habit like honeyvine milkweed, redvine, hedge bindweed and burcucumber. There is really no in-crop option that will provide good perennial vine control. The best one can achieve with an in-crop application is enough vine suppression to minimize harvest issues.
Perennial vines are best controlled with herbicide applications after harvest. The most consistent tactic is to allow the vines to grow back for a week or so after harvest and then apply dicamba and/or 2,4-D. Tank mixing in glyphosate can also increase vine control. For best results go with rates at the higher end of the labels. Continue reading
The two best fall-applied options for ryegrass and poa in wheat are Anthem Flex and Zidua. Pyroxasulfone is providing the grass control in both these herbicides. Anthem Flex can be applied as a true PRE right behind the press wheel. Keep in mind there is some chance of wheat injury from this new use pattern if a rain occurs shortly after planting. As such, if rain is in the forecast wait and apply it later as a delayed PRE or early POST. Continue reading
I have had the opportunity to visit fields where dicamba application/s failed to control Palmer amaranth and observe the success and failure of follow-up weed control tactics. On the positive side, where more timely and diverse weed control tactics were employed Palmer amaranth control was often a success. In a couple of cases, timely Liberty applications on Palmer amaranth escapes often provided 70 to 80% control. Follow-up hooded applications followed by cultivation increased Palmer control in these fields to greater than 95% (Picture 1). Continue reading
A recent new “weed” issue in XtendFlex cotton is volunteer XtendFlex soybean (Picture 1). Recent research has shown that Envoke at 0.125 to 0.15 ozs/acre provides very good control as soon as 7 days after application (Picture 2). Continue reading
Poor performance of dicamba on Palmer amaranth was again the theme of the last ten days. There have been numerous reports typically with attached pictures of large patches of Palmer amaranth recovering from dicamba application/s (Picture 1). Continue reading
JACKSON, Tenn. – The University of Tennessee Institute of Agriculture will host the annual Weed Tour this Wednesday, June 21 at the West Tennessee AgResearch and Education Center. The guided tour will feature about 40 weed management research tests in cotton, corn and soybean. This tour will qualify for Commercial applicator 3 points in categories C01, C04, C10 and C12 as well as CCA 3 points for Crop Management.
Weed Tour runs from 9 – 12:00 a.m., with registration opening at 8:30 a.m. A light breakfast will be served. Continue reading
Just when it appears that ryegrass has become our most problematic weed, Palmer amaranth goes into “hold my beer and watch this” mode. In the last 10 days we have fielded numerous reports on dicamba failures to control Palmer amaranth. Just this past week we were able to visit a number of these fields. Continue reading