Application of fungicide treatments can be a tricky component of corn silage management. Fungicides are effective for two to three weeks, so timing is critical. The best return on investment typically comes when the fungicide is applied at tasseling. The height of the corn becomes an issue at that point, leaving aerial application as the only option, which can be very expensive. The decision to apply a fungicide must be made after making an educated cost comparison.
“Growers should evaluate the silage costs in their area,” says Travis Keene, Mycogen Seeds customer agronomist. “Because fungicide application can be expensive, it must be weighed against potential cost of yield loss.”
Keene provides these tips to help you make a decision:
• Consider the history of the silage field. Does the field have a history of disease pressure?
• Evaluate your tillage plan. No-till or limited tillage leaves more residue to harbor inoculum.
• Corn-on-corn increases the likelihood of disease pressure, as inoculums can overwinter in residue.
• Scout for diseases 10 days prior to tasseling for best results.
• Select hybrids carefully. Work with your seed company to determine if disease pressure is a factor and select resistant hybrids accordingly.
• There is some evidence of early fungicide applications, between the V5 and V8 stage, being beneficial to silage. Early application also means lower cost as the fungicide can be tank-mixed.
• Fungicides act in two ways: preventing new infections or stopping existing infections. Consider which type of fungicide to use and determine the optimum time for application before committing to a fungicide.