Tom Hall, Senior Agronomist, Rooster Strategic Solutions
It’s time to evaluate hybrids. Every August, I make two visits, one to my seed dealer’s variety trial, and the other to the local university’s replicated variety trial. Even though the heat, pollen, and bugs make it a terrible time to visit, it’s the best time to evaluate disease resistance while you can still separate leaf disease lesions from natural corn dry down.
Both these trails are on continuous corn ground, which is the perfect laboratory because if anything can challenge yield and sustainability, it’s a continuous corn rotation. I want the trials to show me what the hybrid can do under the toughest conditions. In fact, it drives me crazy when the trial is sprayed with a fungicide. I routinely tell my seed dealer that I’d rather give up a bushel or two or yield if it means being able to identify defensive hybrids that will stand up and wait for me to harvest. My seed dealer routinely smiles and rolls his eyes whenever I say this!
As I head to the trials next week, I am looking for a few specific things:
- I am obsessive about staygreen. Hybrids that can maintain green in their stalks and leaves normally have the defensive characteristics I want to fight off disease and standability.
- Has tar spot arrived in my area? Tar spot is a very distinctive and damaging corn disease that has not yet reached my fields, but it’s been spotted only two counties away.
- Hybrids with fusarium crown rot can be a complete disaster. It starts with “ghosting,” when a single plant completely shuts down at about tasseling but the ghosted plant is surrounded by healthy plants. In a continuous corn situation, a few ghosted plants one year can turn into a field full of them the following season. A word to the wise: If you have fields with Soybean Sudden Death Syndrome (SDS), make sure that the corn hybrid following is rated for fusarium resistance. SDS and crown rot are caused by different fusarium bacteria but both fusarium species flourish under the same environmental conditions.
- I rate hybrids for gray leaf spot in the trials to see if the seed guide value matches my observed score. It is rare to find a hybrid that is significantly mis-rated, but it happens. I rate the plants on a scale of 1 to 9:
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- 1-2 – no lesions, or a few lesions with no further spread
- 3 – lesions are noticeable on most lower leaves
- 4 – lesions are clearly visible on all lower leaves and few upper leaves
- 5-6 – lesions are plentiful and yield loss is expected
- 7-8 – plant lesions are taking over the entire plant, with 50 percent yield loss expected
- 9 – the plant will die early
- To create a list of new and old hybrids to consider for 2023.
Is it possible to have a drought AND too much rain? Yes, unfortunately. The U.S. Drought Monitor Map (below) has not caught up with the big rains captured in the Midwest and mid-Atlantic. Heavy rain is expected the first week of August in eastern Colorado and western Kansas. Unfortunately, the Missouri Valley has been inundated by floods that have taken lives and destroyed homes and farms. On the other hand, Texas, Oklahoma, and eastern New Mexico are burning up. Ranchers are running out of hay and pastures and are being forced to sell cattle at a loss as their feed runs out. Oklahoma Extension says that more than a million animals may be culled because of the severe drought conditions.
