Lucy Ray from Morgan County recently asked me about ryegrass control in conventional field corn. Here are my thoughts:
- I contacted several local GA corn seed reps to see what conventional hybrids with tolerance to ALS-inhibiting herbicides would be recommended in Georgia. The short list is as follows: Dekalb 68-37 or 66-02 or 111-30; Integra 6588; Dyna-Gro 57CC51; Pioneer 1608 or 17677; and AgriGold A645-16.
- Ryegrass is extremely difficult to control in conventional corn. Expectations should be fair/marginal at best. NO miracles here!
- Three postemergence herbicides are available for use in conventional corn that have some activity on ryegrass (again not great but all we got). These include Accent Q (nicosulfuron), Revulin Q (nicosulfuron + mesotrione), and Steadfast Q (nicosulfuron + rimsulfuron). These herbicides cannot be used if Counter is applied in-furrow for soil insect/nematode management.
- My suggested weed control program for this scenario would be as follows (reduced tillage/strip tillage):
- Prior to planting, if ryegrass and other winter weeds are emerged, split shot of Gramoxone 3SL (paraquat) @ 32 oz/A (~10 days apart) + COC @ 1% v/v (1 gal/100 gal). In the second shot, add Dual II Magnum 7.64EC (S-metolachlor) @ 16 oz/A for residual control of annual grasses and broadleaf weeds. This second shot of Gramoxone + Dual II can be applied before or after planting (but before corn emergence). The goal here is to start off as clean as possible.
- At V3-V5 stage of corn, apply either Accent Q 54.5WDG @ 0.9 oz/A or Steadfast Q 37.7WDG @ 1.5 oz/A or Revulin Q 51.2DF @ 3.5 oz/A + Atrazine 4L @ 64 oz/A + NIS @ 0.25% v/v (1 qt/100 gals). Remember these are not great (for ryegrass/crabgrass) but all we have for POST grass control in conventional corn.
