De Smet, S.D. -It's not a question of if stalk rot will be an issue this year, says Matt Hubsch, lead agronomist for Legend Seeds.
"Due to denitrification across much of our region - the real question is which fields will be impacted by stalk rot," Hubsch said.
Hubsch explains that the tremendous amount of early season rainfall much of our region experienced, many fields experienced denitrification and leaching of nitrogen from the soil.
"Denitrification leads to stalk rot. Because nitrogen is a mobile nutrient, as a corn plant's nitrogen sources dry up, the plant begins to cannibalize itself, forcing all the sugar and energy from the lower stalk to the upper regions of the stalk and eventually focusing all efforts to the grain in the developing ear," said Hubsch, explaining the source and impact of stalk rot. "This causes premature breakdown of the plant."
Signs that a field is impacted by stalk rot include a "V" like yellowing of the plant's leaves. The yellowing occurs from the tip of the leaf and runs back to the mid rib of the leaf in a "V" shape.
Hubsch explains that as the plant breaks down, the lower stalk weakens and becomes susceptible to stalk rot. He says the most common stalk rots in our region are fusarium, which leaves a pinkish color on the lower 6 to 8 inches of the stalk; and anthracnose, which we generally see later in the season, and will leave black lesions on the outer rind, most often in the lower 6 to 8 inches of the stalk.
A weak stalk, infected by stalk rot wreaks havoc at harvest and leads to lost yields.
"Like I mentioned earlier - it's not if your fields are impacted, it's which fields are impacted," Hubsch said.
He encourages growers to test their fields and prioritize harvest those fields most impacted first.
"The pinch test is a simple and effective test. Basically pinch the lower 6 to 8 inches of the stalk. If the stalk collapses, then your field is infected and should rank high on your harvest priority list," he said.
If you have any questions, please contact your local Legend Sales Agronomist. We are here to help.