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Autumn is a new herbicide from Bayer CropSciences that is available for use as a fall-applied herbicide prior to corn planting. Autumn can also be applied up to 30 days before corn planting in the spring. Autumn is not labeled for use on areas that will be planted to soybeans. Autumn is an ALS-inhibiting herbicide which contains the active ingredient iodosulfuron. It should be applied at a rate of 0.3 oz/A. Autumn should be applied with a crop oil concentrate at 1% v/v and a nitrogen fertilizer.

In our research with Autumn last year, we observed good control of henbit and common chickweed with fall applications of Autumn or Autumn plus 2, 4-D (Table 1). Similar levels of henbit and chickweed control were also achieved with Basis plus 2, 4-D and Princep plus 2, 4-D. The addition of 2, 4- D increased control of annual fleabane and corn speedwell compared to applications of Autumn alone. For the price, I generally recommend the addition of 2, 4-D to your fall herbicide to enhance burndown activity and broaden the spectrum of winter annual weeds controlled. As illustrated in Table 1, Princep plus 2, 4-D provided the best control of corn speedwell, which is one of our toughest winter annual weeds to eliminate. We also observed some residual control of waterhemp after corn planting with each of these fall treatments.

Although we have not evaluated these weeds in our trials, other university researchers have also observed good field pennycress, shepherd's-purse, purple deadnettle, marestail, and dandelion control with applications of Autumn plus 2, 4-D in the fall. With some of these species, like purple deadnettle and marestail, the addition of 2, 4-D will increase control significantly compared to applications of Autumn alone.

Kevin Bradley
573-882-4039