But those seeds were not yet ready for the drydown process required for a seed to survive the freezing winter and germinate again in the spring. "So, when the season ended and the corn dried down in the fall and went through freezing temperatures, those seeds were likely killed and very, very few of those would have survived," Goggi explained.
That's why when Iowa State University weed scientist Bob Hartzler recently experimented with a germination test on some fallen corn ears from a derecho-damaged field, he found only about 6% of the corn kernels on the ears sprouted. Those sprouted kernels were likely from corn plants that were able to limp along until they reached black layer in the damaged field, which allowed them to safely dehydrate and survive the winter, Goggi said.
However, even those derecho-damaged fields that didn't get disked down until after the corn seed was mature and had dried down aren't likely to produce vigorous volunteer corn plants, Goggi said.
"Plants that were bent or damaged could have produced seeds," she explained. But those seeds wouldn't have developed fully because they wouldn't have had enough sugar from photosynthesis. "As a result, they are likely not vigorous seed, but of course they can still germinate if they are in the ground with good conditions," Goggi said.
Ultimately, growers should still brace themselves for a high number of volunteer corn plants this spring, Anderson said. "We're hopeful that this means we won't see the astronomical numbers of volunteers we would have thought," she said. "But populations will still be high. Even if only half a percent of the corn that was knocked down comes up in the spring, that's still a lot more than we would normally see."
WHAT KIND OF HERBICIDE-TOLERANT CORN WILL YOU FACE?
Most growers of commercial field corn are aware the hybrids sprouting in their field next year will likely be glyphosate tolerant. But, for growers who plant Bt-traited corn targeting above and below-ground insects, there is a good chance their hybrids will also be glufosinate tolerant.
Several of the Bt traits expressed in corn hybrids are genetically linked with the glufosinate-tolerant Liberty gene, which allowed researchers to track the traits in their corn trials, explained Bill Johnson, Purdue University weed scientist. As a result, many volunteer Bt corn hybrids won't be killed by glufosinate this spring, with the exception of some products such as YieldGard VT Triple, Double Pro, Triple Pro and Trecepta hybrids.
The Handy Bt Trait table contains a column noting which Bt corn hybrid packages will contain glufosinate tolerance in addition to glyphosate tolerance. See it here: https://agrilife.org/….
WHAT CROP ARE YOU PLANTING INTO?
The Stalzers are using tillage this spring as a first line of defense against volunteer corn plants in their derecho-damaged fields, which is one of the most effective ways to tackle the problem, Purdue's Johnson noted.
"Once soil temperatures are above 50 degrees and you get some sunny, dry days, you will start seeing corn germinate," he said. "If you can delay corn planting a little and do some pre-plant tillage, that's probably the most foolproof way to control them."
But for no-tillers -- and tillage weed escapes -- herbicide applications will be the primary tool in the fight to clear your field before planting.
If possible, rotate to soybeans, which opens up the list of grass herbicide options you can use without problematic plant-back restrictions, Johnson said. The Stalzers, for example, are planning to clean up volunteer corn with the Group 1 herbicide fluazifop (Fusilade) in their soybean fields this spring.
If you decide to stay with a corn crop in the spring, be prepared to do some chemical puzzling, particularly for glufosinate-tolerant volunteer corn plants, which take Liberty applications off the table, Johnson said. "The problem is that anything you spray to damage volunteer corn will also damage your real corn crop," he said.
Your options are narrowed to using clethodim (Select), which has a pre-plant interval for corn, and can also have antagonism issues when tank mixed with common plant growth regulator burndown options such as dicamba or 2,4-D, Johnson warned. Antagonism is more likely to cause a problem on larger corn plants so it will be key to spray this mixture on small volunteer corn plants, he added.
Another option is a paraquat-triazine burndown tank mix; but remember contact herbicides like paraquat can only kill volunteer corn plants when their growing point is above ground. So, the most successful applications of this tank mix will be on 7- to 10-inch corn plants, or the V5 growth stage, Johnson said. "Otherwise, you'll just burn off the tops and the plant will still keep growing," he warned.
For more details on how to tackle volunteer corn plants this spring, see this comprehensive look by Iowa State's Meaghan Anderson: https://crops.extension.iastate.edu/….
Progressive Farmer Crops Editor Matt Wilde contributed to this story.
Emily Unglesbee can be reached at Emily.unglesbee@dtn.com.
Follow her on Twitter @Emily_Unglesbee
(c) Copyright 2021 DTN, LLC. All rights reserved.
The Link LonkMarch 23, 2021 at 11:20PM
https://ift.tt/3d1zYYL
How to Manage Volunteer Corn in Derecho-Damaged Fields - DTN The Progressive Farmer
https://ift.tt/3gguREe
Corn
No comments:
Post a Comment