Here is some good information on replanting cotton and herbicides from Dooly County Ag Agent Ronnie Barentine I wanted to share from their Dooly County Extension blog:
Replant considerations where Warrant WAS used at planting:
If replanting cotton is necessary, one needs to consider the herbicides used in the original planting. Cotton is tolerant to the herbicides we use pre-emerge in cotton, with the exception of Warrant and Warrant Extra. Over time the active ingredient (acetochlor) in Warrant is released from the capsules that make it safe at planting. Once released, it can be very injurious to cotton.
Based upon research by Dr. Stanley Culpepper, use the following recommendations when replanting cotton on land that was treated with Warrant at planting:
- Cotton can be replanted 2 weeks after the original application if the land is strip tilled with ripper shank, before replanting. This will dilute the acetochlor.
- If no tillage is performed, wait 3 weeks before planting.
Replant considerations where Warrant was NOT used at planting:
Should replanting be necessary where soil-applied herbicides are used other than Warrant, it is best to run the planter back in the original drill without any soil preparation if soil conditions permit. If reworking the seedbed is necessary then the following procedures are suggested:
Strip tillage: Rerun the strip till rig which should include ripper shanks followed by planting. After replanting, apply a PRE herbicide mixture that includes both a non-selective herbicide to control emerged weeds/cotton and a residual herbicide. The residual herbicide should be different chemistry than that used with the original planting. It is likely the residual herbicide used with replanting may offer limited residual Palmer control; thus, the first early POST application must be made quickly after replanting in a Roundup Ready system (likely 10 d or less).
Conventional Tillage: For growers who do not have strip tillage implements, use shallow tillage such as light disking. Do not re-bed without first disking. Re-bedding without disking can lead to severe injury. The amount of time that has passed and the amount of rainfall that has occurred between herbicide applications and replanting will determine the need for additional herbicides.In general, additional herbicides will be needed when replanting but one should switch residual herbicide chemistry from that used during the first planting.
Glyphosate, paraquat, or Liberty must be included to control emerged weeds and cotton when replanting. Paraquat (Gramoxone, others) or Aim will control small emerged cotton. Liberty is also effective controlling cotton as long as it is not a cotton cultivar tolerant to Liberty.