Friday, July 6, 2012
Are Your Corn Roots Discolored?
If you take a spade or shovel and pry a corn plant out of the ground, shake off the soil and split the crown at the level of the soil what do you see? Do you see bright white, healthy tissue like the picture above or do you see some discoloration?
We have been finding corn crown roots with yellowish, brownish or black areas in the crown root all season. Yes there is plenty of corn with white crowns but it is hard to not find discoloration in every field. What is the cause of this?
No one knows for sure but it seems to be a type of bacterial or other unknown disease. We have been encouraging farmers and consultants to send plant samples to the University of Nebraska Plant Laboratory to check for Goss's Wilt which showed up big time in Iowa and surrounding states last year.
The sick plants often show a pinkish leaf at ear fill. It could be Goss's or it could be something else but it seems to tag along with Goss's and other ailments. The big thing is this corn crop in the United States is a lot sicker than anyone knows and it is not all due to drought.
In fact we thought there would not be as much Goss or similar wilts in drought conditions but when a plant wilts, what causes it?
This week we have been looking at sodium levels in the tissue test. It seems the higher the salt content in the leaf tissue the less wilt that is observed. To document this, one group actually sprayed sea salt at the rate of about 5 lbs per acre with 20 gallons of water on wilted corn and after it was sprayed, it stood up and quit wilting. Now I have been trying to correlate wilting to my tissue sodium levels and there seems to be a correlation but I am not sure. There are so many factors affecting the crop right now it is difficult to isolate just one.
If you grow corn or knows someone who does, go dig some plants and look at the crown roots. Tell me what you see. If you tissue sample, look at the NA or Socium level in the leaf tissue compared to the wilting you see in those spots. Is there a correlation?