Bill Johnson wasn't surprised when a farmer told him that he applies Sharpen and Authority, and that the two labels speak differently when it comes to mixing each product with the other.
In fact, Johnson already knew what they say – Sharpen says don't mix with Authority, and the Authority label doesn't even address it. Sharpen is made by BASF; FMC makes Authority.
Johnson, Extension weed control specialist at Purdue University, says companies take different positions when wording their labels. Here's another example. Since the product first appeared, the Sharpen label has changed. To cover the product in a few instances where unusual circumstances led to damage, the Sharpen label says it must be applied 28 days before planting.
If you applied Sharpen within a week of planting, or even after planting, you're not alone. Just know that you are on your own if something goes wrong, because the label specifies something different.
Johnson says the most graphic example in differences on labels is in generic 2,4-D labels. The chemistry is marketed under a number of different brand names.
"Many of those vary widely in the amount of time required after application before you can plant, especially ahead of planting corn," he says. In fact, he says the labels have been all over the board on this issue.
They're starting to gravitate toward about a week before soybeans, but there are still differences, Johnson advises. If you're going to use one of these products in the future, you need to know what the label for the brand that you are using actually says in terms of plant-back restrictions.
If something goes wrong in terms of crop injury, the label will be the position that counts, and not that some other brand, even if it's the same chemistry, allows something different, he notes.
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