Part II: Second Harvest Aid Application
By Adam Hixson, BASF Technical Service Representative
Last month, I talked about using Sharpen® Herbicide in the first harvest aid application. Sharpen dries out the leaves on the cotton plant and crisps up any weeds, such as Palmer amaranth, morningglory and bindweed, that are in the field at harvest time.
However, after the initial application, moisture under the cotton and moderate temperatures can create the potential for regrowth. It typically occurs close to the main stem of the plant and can delay harvest. The fresh, lime green juvenile leaves may also stain the lint as it goes through the stripper or picker. This staining results in a low color grade, leading to dockage at the gin.
Where I think Sharpen shines is its ability to dry down and desiccate regrowth. One of the reasons I never like to go above 1 fluid ounce of Sharpen in the first harvest aid application is because this practice allows you to use Sharpen in the second application. Ten to 14 days after the initial harvest aid application, I recommend applying Sharpen @ 1 fl oz/A + MSO @ 1% v/v + AMS @ 8.5 lbs/100 gallons. We call this the “kill shot” to eliminate regrowth.
The second application also desiccates any mature leaves that were left in the lower canopy at the bottom of the plant. This is especially helpful if you’re dealing with a large cotton plant that had a lot of foliage on it.
Another benefit of using Sharpen in the second harvest aid application is its short pre-harvest interval that allows growers to harvest on their schedule. Five to 7 days after the second application is a good estimation of when you can start harvesting the crop. The timing is typically mid- to late October.
When using Sharpen in a second application, the major consideration is good coverage. I recommend 15 GPA minimum spray volume by ground and 5 GPA by air. Sharpen is a contact herbicide that must touch every leaf you want to desiccate or dry up. To achieve the best coverage, choose nozzles that produce medium-sized droplets.