Ag Professional Weekly
Jun. 22, 2009
Source: Mycogen Seeds news release
Taking time this summer to scout cornfields can mean the difference between a successful harvest or losing yield to diseases and insects. Although it is important to scout fields being harvested for grain, early season scouting can return even greater benefits in silage corn.
"Diseases and insects affect yield and standability, but also have a major impact on forage quality," said Mark Riehl, customer agronomist at Mycogen Seeds.
"When growing grain corn, we want the plant to take full advantage of its leaf area in order to optimize ear growth and kernel development," he said. "With corn silage, we need grain fill but we also want to protect the integrity of the leaves and stalks throughout the season."
Riehl points out that leaves in good condition are more easily digested and increase tonnage at harvest. Therefore it is critical to keep all leaves as disease- and insect-free as possible, not just the ones affecting grain fill. Early scouting can help catch problems before plant damage becomes significant.
Diseases that cause the most economic damage to silage include gray leaf spot, northern and southern corn leaf blight, eye spot and corn leaf rust. It's important to learn the distinguishing characteristics of these particular plant maladies for accurate identification and treatment, Riehl said.
"Several universities offer disease identification guides, as well as newsletter updates on diseases and insects that have been spotted in your area," Riehl said." If you are not on a mailing list for these reports, it would be a good idea to subscribe to a local newsletter and keep alert for potential threats."
Riehl recommends that silage growers start scouting for diseases near the end of June or the beginning of July. Timing can vary depending on geography and the stage of plant development, but the key is to get into the field about 10 days before tasseling begins.
"If a problem is spotted, it is important to take action as soon as possible," Riehl said. "Because most fungicides are preventive, the earlier you can apply the treatment, the better the control will be. Under the right weather conditions, even a few diseased specks on the leaves can become a serious issue if not treated."
