Diseases to Track in 2020

Tar Spot on corn with Black raised “bumps” and small necrotic fisheye symptoms. ( N Kleczewski and J Donnelly )

Planting is just the first step in the battle for high yields. As soon as seeds hit the ground, they’re under attack from various predators – namely fungus and disease.

“This could be a big year for fungicides,” says Mike Kavanaugh, AgriGold national agronomy manager. “Anytime it’s warm and wet for corn it’s a good year for fungicide.”

Diseases to watch in corn:

  • Southern Rust
  • Common Rust
  • Tar Sot
  • Physoderma
  • Early Crown Rots
  • Northern Corn Leaf Blight

Diseases to mind in soybeans:

  • Pythium
  • Rhizoctonia
  • Phytopthora
  • Sudden Death Syndrome
  • Frogeye Leaf Spot
  • White Mold

“Check hybrid and variety tolerances, know if certain ones are at greater risks, scout fields and see how it’s going along throughout the season,” says Dana Harder, Burrus agronomist. “Check for disease above the ear shank, consider if you have the ability to dry corn—you might not want to spray if you don’t have drying capacity. But if the infection is bad enough, you’ll see positive ROI from fungicides.”


Southern Rust:

A close up of a map

Description automatically generated 2019 data University of Wisconsin

Southern Rust doesn’t overwinter in corn residue. Instead, live spores travel from south to north with wind, equipment and through other physical carriers. Watch maps in 2020 to know if you’re in or near a county with confirmed Southern Rust. If it appears in vegetative stages, it’s a good idea to spray a fungicide to avoid potential yield loss.