• By Clay Perkins •
Questions continue to be asked on how to best manage junglerice, barnyardgrass and goosegrass in cotton and soybean.
Research earlier this spring looking at grass control after an initial glyphosate + dicamba application showed that if a follow-up glyphosate application was applied seven days later better than 90% junglerice control could be achieve (data below). Goosegrass control responded similarly (data not shown).
Junglerice control was less than 80% with a lone glyphosate application. A sequential application of glyphosate spaced seven days apart was needed to provide adequate control.
In addition, a follow-up application of Liberty + glyphosate provided very good grass control and would be a great fit in an Enlist cropping system.
Finally, this research has shown that we are seeing a clear shift towards increasing glyphosate tolerance in our junglerice, barnyardgrass and goosegrass populations.
Some ask about adding 9 or even 12 ozs/A of a 2 lb. clethodim product. In our research, adding a pint of 2 lb. clethodim greatly helps the control on all three of our most troublesome grass species.
Do not forget to add crop oil concentrate (COC) with your clethodim. We have seen that the clethodim is working slower this year than last year so be patient when evaluating the results.
Clay Perkins is a University of Tennessee graduate research assistant. He may be reached at clamperk@vols.utk.edu.