Dr. Prostko shared some questions received over the last few days:
Select 2EC @ 8 oz/A or Select Max 0.97EC @ 16 oz/A (or generic equivalents) + 1% v/v COC would be a good choice for this problem. Remember that ryegrass stage of growth is important (Figure 1) and that temperatures below 50 F can significantly reduce control. Higher rates of paraquat (3.5-4.0 pts of 2 lb ai/gal) can also be effective but 2 applications (10-14 days apart) may be needed.
|Figure 1. Influence of clethodim timing on ryegrass control.|
2) What is the best nozzle to use for soil applied residual herbicides?
Generally, nozzle type is not as critical with soil applied residual herbicides when compared to postemergence herbicides. For many years, I used a flat fan nozzle (11002DG) for all my weed control trials. Recently, I started using an AIXR11002 nozzle as my standard. I have also applied soil residuals with a TTI-02 nozzle. I have not observed any reductions in the performance of residual herbicides when using these larger droplet nozzles. Check out Figure 2 for a quick look at the coverage provided by these different nozzle types. However, I would suggest that growers refer to the nozzle manufacturer for more specific information about the potential performance of nozzles with soil residual herbicides.