We recently rated our Italian ryegrass screen in the greenhouse for glyphosate and clethodim resistance. The first two runs were conducted on 13 populations across 11 counties in West Tennessee. Continue reading
Practically every fall some growers are dismayed at the vine infestations present at corn harvest. Often, these weed infestations emerged after the 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
My understanding is that Tennessee may have as many as 100,000 acres of canola planted this fall. Weed management in canola can be difficult, but is fairly straight forward for 2 reasons. Continue reading
Italian ryegrass is becoming one of the most troublesome weeds in the Mid-South for many reasons, including herbicide resistance. Herbicide-resistant Italian ryegrass is particularly problematic due to its ability to survive applications of glyphosate and clethodim. The most effective way to control ryegrass is to prevent emergence by applying residual herbicides in the fall. Tennessee has many relatively hilly fields, which raises concerns about soil erosion without some winter plant coverage. Although fall residual herbicides are effective for controlling ryegrass, the limited time available during the busy harvest season often makes applications impractical. Continue reading
Pigweed problems are nothing new for growers across the region. With Palmer amaranth having confirmed resistance to five herbicide modes of action in Tennessee, control options continue to be limited. Historically, bleacher (Group 27 HPPD inhibitors) applications have provided sufficient control, especially in corn. In recent years, there has been growing concern for the level of control observed when using these products. Continue reading
Serious infestations of goosegrass have proven to be way too persistent in many cotton and soybean fields (Picture 1). Many are getting frustrated with the lack of control seen with tankmixes that contain glyphosate and/or clethodim. Some have asked if maybe some of these grasses have developed resistance to glyphosate and/or clethodim. Continue reading
“We are going to run out of money before we run out of pigweed” one veteran West Tennessee weed manager stated last week. That really sums up where we are now in many fields. These are fields where frequent rain has made timely POST applications very hard to get done or in fields where timely applications were made but herbicide resistance limited the control. Fortunately, that does not describe every field as many are relatively clean. Overall this year though, it is clear we will have to live with Palmer amaranth in more fields than we would like. Continue reading
Herbicide-resistant Palmer amaranth observations and calls have started. Most recent calls have been from some who have switched from Xtend to Enlist crops. They are finding that the sketchy pigweed control in Xtend crops they experienced in previous years is also problematic in an Enlist crop. This would be consistent with our research that has often shown that Palmer amaranth that is resistant to dicamba is cross resistant to 2,4-D. Continue reading