URBANA, Ill. — Farmers going to the field this spring will be using a brand new type of soybean. Todd Gleason has more on why dicamba-resistant varieties will require them to exercise caution when making herbicide applications.
Dicamba is a very old herbicide. It has been in use for more than four decades. It kills broadleaf plants and one of the most sensitive of these says University of Illinois Extension Weed Scientist Aaron Hager has long been the soybean.
Hager : It is one of the most sensitive broadleaf species that is grown in Illinois. You can look in the literature and find studies that have been done now for forty or fifty years really trying to look at how soybean are.
Recent work out of Missouri indicates sensitivity down to a rate of one-twenty-thousandths of a field use rate. There are many things listed on the dicamba label that will legally bind farmers planting dicamba and spraying resistant varieties. Even pre-season prohibitions.
Hager : We will give one example. If we are look at the Extendimax label, which is a straight dicamba formulation from Monsanto, there is a requirement to have a buffer area. A downwind buffer area. The size of that buffer area would vary depending on the rate that is applied. So, an in crop application that would require half-a-pound of dicamba acid would require a 110 foot buffer. However, if we are using decamba now in this pre-plant or pre-emergence time frame, when we are allowed to go up to a full pound at that application, if we do that the buffer goes to 220 feet.
This is not a recommendation. It a restriction. There is a big difference says Aaron Hager and farmers planning to use dicamba on dicamba resistant soybean fields this season must understand the consequences.
Hager : These statements on these labels are not recommendations. These are things that must be followed every time these applications are made. So, for example, if you elect not to follow something like the nozzle selection type, or the height of the boom above the crop canopy, you are now violating this federal label.
This story has listed just a few of the restrictions; the downwind buffer, the nozzle selection type, the height of the boom above the canopy. There are others including speed, temperature, inversions, and predicted rainfall events. The point says Hager is that farmers choosing to use dicamba resistant soybeans this season and spraying them with decamba must read, understand, and follow the labels.
— Aaron Hager, Extension Weed Scientist – University of Illinois
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