Crop Scene Investigation - 17: Bruce's dilemma: Replant after frost damage or hope for the best?

Monday, March 2, 2009

by SHAWN BRENNEMAN


Early planting gives growers a great opportunity to maximize yields and get a head start on the growing season, but it can also put the young crop at risk of setbacks. My phone is always ringing in spring as I help growers through these challenges.

"My corn is brown and droopy," said Bruce, on the phone from his Lambton County farm on May 14. The crop was planted early and had reached the three-to-four leaf stage. "We've had some pretty cold nights, so I'm thinking it's frost damage, but I'd like your opinion."

I agreed to go and take a look. On the way to the field, I considered the other possible problems. Herbicide drift or carryover could result in similar leaf symptoms.
"Why are you so sure it's frost?"

I asked Bruce when I arrived at his farm. "Well, it got pretty cold a couple nights ago, cold enough I had to grab an extra blanket. I just noticed the damage today in my crop tour. My neighbour's crop looks the same and he's already re-planting. I'm probably wasting your time. I should just get into the field with the planter and start again like my neighbour," said Bruce.

I reassured him that he had made the right decision in calling me. "Let's not jump to any conclusions, even if things seem obvious," I said. We looked at recent weather data. Three nights earlier, the air temperature in the area did get down to 3 C. This meant that the ground temperature could easily have gotten down to -2 or -3 C, cold enough to injure the corn. It was obvious that frost was the root of the problem, but I wasn't yet certain if Bruce should replant.

In the field, I took a closer look at the droopy brown plants and also noticed water-soaked lesions, a result of the plant cells freezing and then bursting.
The key to assessing if corn seedlings will recover from frost damage is to find and observe the growing point.

We pulled out several plants and split them lengthwise. The growing point was still white and healthy looking with no sign of slime or rot. Five days had now passed since the frost. The original planting date was April 20.

Would you replant if you were in the same situation as Bruce?

Send your solution, along with your name, address, and telephone number to Better Farming at: rirwin@betterfarming.com or by fax to: 613-678-5993.
Correct answers will be pooled and one winner will be drawn for a chance to win a Wireless Weather Station.

The correct answer, along with the reasoning followed to reach it, will appear in the next issue of Better Farming. BF

Shawn Brenneman, CCA, is a Sales and Agronomy Manager for NK® Brand, Syngenta Seeds. He is based near Tillsonburg.