This fall, we have been seeing quite a bit of stalk rot in the fields of our customers. Stalk rot (fusarium, anthracnose, gibberella, diplodia, etc.) has affected many fields and will impact harvest and increase harvest losses. Pictured above from left to right are anthracnose, gibberella, fusarium.
Winfield Solutions recently put out a Technical Bulletin on this very topic. They outlined two different methods to scout out stalk rots:
For the “Push Test” randomly select 20 plants from five different areas of the corn field (100 plants total). Push the top portion of the plant and note whether the plant lodged or had the stalk strength to remain standing.
The “Pinch” or Squeeze Test” involves an assessment of the lower stalk. Again, randomly select 20 plants from five different areas of the corn field (100 plants total). Remove the lower leaves and pinch or squeeze the stalk above the brace roots. If the stalk is easily squeezed, with moderate pressure, it is rotting on the inside. Record the number of rotted stalks. Regardless of which method is used, if 10-15 percent of the plants are lodged, stalk rot is prevalent in the field. If this condition occurs, early harvesting should be considered to prevent losses, as the corn stalks will have less time to rot, and subsequently lodge in the field. Extra grain drying costs may be incurred, although those costs could be covered by better harvest efficiency.
So, what is causing stalk rot?
A recent article on AgWeb by Ben Potter breaks it down easily for you:
Knowing what has caused corn root or stalk lodging may help determine the best next course of action. Here are four common causes:
- Weather – believe it or not, strong-enough winds can sometimes overcome even the best root development. Also, hail-damaged corn is almost certain to experience some stalk rot if the event happened after pollination.
- Insects – corn rootworm larvae have been known to cause root lodging. And the Eurpoean corn borer can tunnel into the corn ear shank and cause ear-dropping, or tunnel into the stalk can cause stalk-lodging.
- Diseases – several stalk-rot pathogens can infect corn roots or injured areas of the stalk. High incidences of foliar disease such as gray leaf spot and northern corn leaf blight can predispose corn to stalk rot.
- Stress – any number of stresses can factor, including high plant populations, extremes in soil moisture, nutrient deficiencies or imbalances, drought, corn-on-corn rotations and more.
What can you do about it?
By recognizing stalk rot early, you can plan to get your crops off the field to prevent further damage.