In this update from Pioneer, agronomist Dan Emmert discusses early season weed control. He says the best thing we can do is prevent those weeds from emerging, especially when it comes to waterhemp and Palmer amaranth.
“When a seedling is emerging, it has one growing point. By the time that waterhemp is 2 inches tall, there are 7-9 growing points on it. When it gets to 6 inches tall, there are over 30 growing points. So, if we want to completely kill the weed, we have to kill every single one of those growing points. The easiest way to do that is to lay down a good herbicide with some pre-emergence activity and not just do that at planting but come back again about a month later and with your post application include another residual.”
So, with fields that were planted the first week of April, that time is now.
Emmert says as he was walking fields last week, he saw quite a few very small seedlings that were breaking through the residual because of how dry it was prior to last week’s rains.
“As things dry out and as we’re able to get back into the field, getting that post-emergence herbicide on before those weeds get too tall and are harder to kill, it’s going to be very important. And not just laying down that residual, but also including effective modes of action beyond just glyphosate or Liberty as we try to take out those waterhemp that have already emerged. With that, it includes using at least 15 gallons per acre of water, the right surfactants, and also the right nozzles to make sure that we’re getting adequate coverages of those small weeds.”