By Dave Nanda, Director of Genetics and Technology for Seed Consultants, Inc.
Before the summer of 2011, it was generally assumed that high temperatures and humidity would cause high incidence of corn diseases. But the diseases did not spread where it was hot and dry, even though lower leaves had lesions present. We speculated that perhaps it was too hot and dry for corn and soybeans and also for leaf diseases. Was that a correct assumption?
Well, after crisscrossing the states of Indiana from Warsaw, Valparaiso, Decatur, Brookston, Kokomo, Seymour, Scottsburg, Terre Haute, Jamestown, New Castle, Batesville, Shelbyville, Versailles, Indiana to Bradford, Celina and Washington Court House in Ohio, during our Kick-off meetings, field days and crop scouting trips, and observing a lot of corn and soybean fields, I came to the conclusion that our assumptions were correct. If is too hot and dry for corn and soybeans, it is also not favorable for the disease organisms. Wherever they received sufficient rains, the crops looked decent, but the diseases like Northern Corn Leaf Blight and Grey Leaf Spot were also prevalent.
Lessons from the 2011 growing season include:
• Fields planted earlier did better.
• Plant your crops as early as possible.
• Late planted crops can catch up.
• Diseases also need moisture to develop and spread.
• Good year to select varieties for heat and stress tolerance.