Back in the days when AgriEnergy Resources founder Dave Larson taught at Renewable Farming seminars, Dave’s goal for black-layer maturity corn was this:
“At physiological maturity, the corn stalk should be green including most of the upper leaves above the ear. The hanging ear should be in a bright white husk. A living stalk allows moisture in the kernels to move back into the stalk — drying down naturally. A dead stalk locks moisture in the kernels.”
We’ve raised many corn crops just like that. But it’s a bigger challenge every year. This season, our corn had lost most of its green leaves by late September. We had not provided enough nutrition for the crop to defend itself. Most of our late foliar attention was spent on soybean plots, which are just now transitioning into yellow leaves as of September 29. All the neighboring soybean fields are harvested.
This morning, Keith Schlapkohl of Stockton, IA sent these two photos of his corn at the site of the Sept. 2 field day with BRT Ag & Turf.
The first photo was taken late in the field day Sept. 2. Corn is a bright green, with only a little firing on lower leaves as the plant translocated nutrients into the kernels.
“The challenge is to keep the corn crop alive another month, to gain kernel fill time,” Keith said this morning. So many diseases, from Northern corn leaf blight to Goss’ wilt, are endemic that even a well-nourished field faces a challenge to keep healthy.
In fact, Keith and his crop consultant Amy Bandie saw a need to fly on some nutrition plus WakeUP in mid-September to fend on a Northern corn leaf blight attack on one susceptible corn hybrid.
As of Sept. 28, the same field shown above is still hanging in there… white husks on mostly green stalks. We’ve noted that when cornfields dropped dead in early September, the entire plant including the husk turned a dead brown or gray-brown.
For more detailed information on keeping corn alive, read consultant Bob Streit’s latest crop report on our site.
As consultant Bob Streit observes in his Sept. 29 report on this site, even healthy cornfields were being invaded by disease inoculum through September.
Aerial applicator Rick Kettley of Steward, IL, sees hundreds of thousands of acres through the season, and thus has a unique overview of corn disease progression. This season in northern Illinois, the first Goss’ wilt signs emerged in early July. “We had some little circles of dying corn about July 10. The diseased patches gradually expanded and merged.”
We’ve also seen these symptoms in earlier seasons, as we like to fly low in powered parachutes. As we understand it, this pockmark pattern points to the disease being carried in via the seed corn. (Seed fields get infected too.)
This fall, Kettley observed how Goss’ and possibly other diseases invaded healthy cornfields carried on the wind. “You could see waves of dying corn along the edges of fields. Sometimes 20 rows deep, sometimes 30, as wind currents varied,” Rick tells us. See the photo below, sent to us by Keith Schlapkohl. It’s a field in southeast Iowa.
Plant pathologists point to other diseases alongside Goss’ wilt — often they say that the problem is Northern corn leaf blight or several other problems which induce stalk rot, and not Goss’ wilt at all.
Farmers willing to spend the rescue treatments staved off the bacterial and fungal disease advances with nutrition mobilized with WakeUP, tank-mixed with bacterial/fungal applications.
“But fighting back with fungicides and bactericides isn’t a permanent cure,” worries Keith Schlapkohl. “We have to be concerned about the long-term impact of any toxins on our beneficial soil organisms.”
Pesticides generally lead to more pests, and a “need” for more pesticides. That’s a well-understood (but still controversial) observation.
What if — What if corn diseases begin earlier and earlier each season, in wider and wider regions of the country? That would be a continuation of the pattern we’ve seen the past several years. Crop consultant Michael McNeill has been asking that question at many presentations to farmers. So far, we haven’t seen someone come up with an answer.
Published Sep. 29, 2015
Updated Sep. 30, 2015