Two weeks ago, Dave Nanda would have said there was still 200 bushels per acre of potential on the Crop Watch 2015 field. Planted on May 4, it escaped some big rains. But now the yield potential is not as certain.
Crop Watch 7/10: Weather conditions favor foliar diseases on corn
Why? Bigger rains have hit he field over the past two weeks. It is still in good shape overall, but the weather has provided several consecutive days of damp, cloudy weather and cool temperatures over extended periods.
Nanda, consultant for Seed Consultants, Inc., noticed several things on a recent visit to his field that bear watching. Time will tell how they play out to affect yield potential. Unfortunately, it may be too late to take action to help the crop if you wait until the signs are obvious.
Here are five things Nanda believes deserve watching through the rest of the growing season.
What will diseases do? From one spot on a lower leaf a week ago to a dozen spots now, Nanda believes that conditions are right for diseases to hammer certain fields. Whether it becomes rampant in the crop watch field remains to be seen.
So far the lesions are Northern Corn Leaf Blight lesions, he says. The disease got a good foothold last year in many areas due to cool weather, and is already appearing early this year. Even hybrids with a decent tolerance package could be affected if disease pressure is severe. Gray leaf spot is also likely to be a concern, particularly if it stays moist but temperatures climb back toward normal during the back half of the season.
Nitrogen deficiency. It's the $64,000 question for everyone this year. By tasseling, firing on the lowest couple of leaves was pronounced. "We were seeing classic symptoms where the leaf turns brown at the tip and it runs back toward the center of the leaf," Nanda says. It may not be apparent if plants run out of N and it affects yield until later in the season, he observes.
Insects. Did rootworm larvae get washed away as well as many crops or not? Some entomologists are guessing they did. However, in this field conditions weren't flooded when larvae hatched. Some rootworm beetles were flying by mid-July.
Hybrid differences. Since two hybrids are in the field, it will be important to notice how each hybrid is handling disease pressure during the rest of the season. With different genetic backgrounds, the response could be different.
Crop Watch 7/6: Tasseling is just a few days away in Crop Watch field
Walk or fly. With wet conditions during the growing season, it's been difficult to get very far into many fields, including this one. This would be a good year to fly fields, either in a plane or with a UAV to look for variation in crop performance.