A few reminders based upon my phone calls and e-mails over the last few days (click on Figures to view in larger format).
Herbicide Resistance Info
1. Revenge spraying large pigweed plants is not a viable option for growers who have been untimely due to rainfall or other circumstances (Figure 1). Options for escaped weeds include hand-weeding or using a 50% solution of paraquat in a non-selective applicator (NSA) (Figure 2).
A NSA is more effective in peanut than soybean due to the height differential between the crop and weed (i.e. more of the weed gets treated in peanut). Check out page 215 of 2017 UGA Pest Control Handbook for more information about the use of NSA in peanut.
2. Options for controlling Florida beggarweed in peanut at this time of year include a postemergence application of Classic, paraquat in a NSA, hand-weeding, or mowing.
Our data has shown that when grown under weed-free conditions, Classic can cause 7% to 11% yield reductions when applied to GA-06G. Thus, growers who want to use Classic must weigh this potential yield loss against the negative effects that large beggarweed plants can have on fungicide deposition and harvest efficiency as the season progresses.
If beggarweed populations are dense enough to impede fungicide deposition and/or cause a digging nightmare, the use of Classic is justifiable. Check out page 214 of 2017 UGA Pest Control Handbook for more information about the use of Classic in peanut.
3. Field corn producers with pigweed and tropical spiderwort/Benghal dayflower (TSW/BDF) problems need to seriously consider a post-harvest control strategy (Figure 3 and 4).
Post-harvest control programs for field corn are presented on page 86 of 2017 UGA Pest Control Handbook. Post-harvest control programs for TSW/BDF are discussed on page 73 of 2017 UGA Pest Control Handbook.