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southern MN | Soybeans are extremely sensitive to dicamba. When little, they can outgrow damage. Later in the season they take on much more damage.
Dicamba volatilizes much more in hot mid summer when beans would be sprayed. Not as much when it’s cooler, typical corn spraying time.
Corn doesn’t really like dicamba so much, so we were using low rates and had to spray when the corn was little. The trained beans can take it heavy dose and latter into their growing season so the rates are much higher, more product out there to volatilize.
There is some speculation that Monsanto concentrated so hard on making a product that will not drift; what they ended up with was a product that lingers a long time it doesn’t break itself down or volatilizations as fast, and is more likely to catch a temperature inversion a day or two later and sneak out that way.
The early rules to spray with no wind and so forth again put many people spraying exactly when a temperature inversion was most likely to form. Since then they have changed the rules so that there really is no proper time to spray you just have to ignore the rules if you want to use the product.
Temperature inversion is when fog forms, or heavy dew forms and is more common later in the growing season, not early when corn spraying. These are the worst times for a volatile product like dicamba, as it can be rewetted and gas off and forms a cloud that moves very slowly (little to no wind in a dew or fog) and as an intact cloud over neighboring fields.
Put it all together and the risks of something going bad is just so much higher the farther into summer you go.
Paul | |
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Dicamba Question
