Corn School: Fine-tuning a fungicide strategy to protect yield potential

Every corn crop is different. The year-over-year variables really play into a fungicide timing strategy, but the most important question to ask when strategizing for fungicide timing may be: “What is your corn crop doing right now?”

Ken Currah, with BASF Canada, joins RealAgriculture’s Bernard Tobin for this episode of the Corn School to walk through the fungicide decision making process. The V5 or V6 stage is when a corn plant will start to determine how many kernel slots to set up in a harvestable ear, total kernels around (influenced by hybrid), and kernel length.

A healthy, uniform crop with some moisture underneath it at this stage has yield potential and you want to protect that potential.

There are a lot of things to think about in regards to this fungicide strategy. Western bean cutworm, although it’s an insect, acts as a vector for spreading silk channel infection of fusarium and giberella ear rot, which lead to DON and vomitoxin issues later on. Spray an insecticide when western bean cutworm is present and above threshold, and always follow best management and stewardship practices.

Strobilurin-based fungicides can be used for northern corn leaf blight, eye spot, grey leaf spot, sometimes rust if it’s an issue. Keeping leaves clean helps maintain and protect the yield potential already built. The proper staging for these products is when about 75 per cent of the crop has green silks that protrude about an inch, Currah says.

Remember too that multiple modes of action in fungicides are just as important as in herbicides. “Multiple modes of action is only true if all modes in the jug or in the product are actually active on the target disease,” says Currah. Single mode of action fungicides will only lead to trouble down the road says Currah, especially from a stewardship standpoint.

“We see a yield increase in over 90 percent of fields, we see a positive return on investment in 80 per cent of our fields,” explains Currah on the expected pay-off from using a fungicide. Capitalizing on plant health benefits should not be discounted when considering fungicide ROI, he says.

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