This has ,clearly, been the worst year for ryegrass in the state in both corn and wheat. There are a good many corn fields that are clean where the burndown was glyphosate + clethodim. Fields where dicamba was added in the burndown are, in most cases, the most infested with ryegrass. As mentioned in a previous blog, other than just going out and spraying the typical POST corn application and hoping that pushes the ryegrass on to maturity there is no real solution to controlling it.
The wheat fields that were consistently clean of ryegrass were those treated with either Anthem Maxx, Zidua or Axiom last fall. A good bit of the ryegrass population in the state is resistant to ALS-inhibiting herbicides which renders herbicides like Osprey, Finesse, and Powerflex harmless to ryegrass. Axial Bold has shown improved ryegrass control in spring applications over those ALS-inhibiting herbicides but it does not offer the consistent ryegrass control as those delayed PRE-applications of Anthem Maxx, Zidua or Axiom.
Johnsongrass is also a consistent problem in a good many cornfields. Glyphosate is just not providing any traction in the burndown on Johnsongrass and the POST in-crop applications are no better. In our most recent research funded by the Tennessee Corn Check Off program has shown that Steadfast Q or Accent Q can still provide good control of Johnsongrass when glyphosate fails.