Research has shown understanding the time interval between sequential post applications is one of many critical components for an effective weed management system.
The figure below compares 6″ Palmer amaranth response to sequential Liberty applications as influenced by interval between applications.
Obviously, one needs to apply Liberty when the biggest pigweed in the field is 3” for complete control and in this event a follow up application can be made when the next flush of pigweed reaches 3”.
With the challenging weather during 2020, spraying all weeds at 3” or less may not be practical for some fields; thus, when pigweed is too large to kill with the first application then the second application timing is important.
Do not make more than two Liberty applications in a season for resistance management purposes; follow the second Liberty application 10-12 days later with a lay-by directed application including conventional chemistry such as Diuron + MSMA + Crop Oil or Roundup + Diuron (add Envoke with lay-by if morningglory or nutsedge is an issue; check carryover restrictions)!
A few critical points from the label:
- One must have the following 24 (c) label in hand when making application (click on label picture to make larger);
- Liberty may be applied twice over-the-top of glufosinate-tolerant cotton as long as there is at least a 5 day interval between applications;
- Do not include tank-mix partners when making two applications less than 10 days apart.
- Do not apply more than 36 oz/A over-the-top of cotton per application.