Stalk quality could affect harvestability and provide challenges during the 2018 corn harvest.
Keep In Mind
High yield levels for many area fields have mined nutrients from the lower stalk and roots in order to complete grain fill. A very large ear on a soft stalk is simply bad physics and gravity eventually aids in stalk collapse. Some hybrids have late season plant health compromised by grey leaf spot, northern leaf blight or anthracnose. Heavy rain and high winds can increase the likelihood of stalk collapse.
Identifying fields with corn at risk of going down is a high priority. Pinching the lower stalk with your fingers between the lowest two nodes is one way to easily identify soft stalks. Pushing stalks over from the top to a 30°angle is another way. Be aware of the impact late season anthracnose has on fields, such as the tops easily collapsing.
Tracking the fields and hybrids impacted by disease is important. Your Sunrise agronomy team can be very helpful in discussing causes and management decisions to limit impact. Crop rotation and residue management can help reduce the impact of disease in the future. Future management of late season plant health nutrition with the addition of a foliar fungicide and disease control with the addition of PCT | Sunrise® FolrFeed® Corn Foliar Extra can also aid in stalk quality.
Types of Ear Rot
Anthracnose is typicaly seen in late August to early September. It starts at the top of the plant and shows a rapid change from green leaves to yellow to brown. We call this the “golden glow.” This is the primary cause for the loss of upper canopy tissue or “top die back.” Foliar fungicides have no impact on the disease as it comes in well past residual persistence of fungicides.
Anthracnose can also be found in lower stalks with shredded pith tissue and a distinct black color to the stalk rind. This is typically the most common stalk rot we see in our area.
Diplodia has shredded pith and small black spots on the lower internode rind that you cannot easily scrape off with a fingernail. Warm and moist conditions favor Diplodia growth.
Fusarium has brown streaks on the rind and sometimes pink colored tissue can be seen. Some white discoloration of tissue can be seen. Most prevalent in hot and dry years.
Gibberella has small black spots on the rind that you can easily scrape off with a fingernail. The pith becomes shredded and turns pink. Warm and moist conditions favor this disease.
Pythium has decay of the crown and first internode. Typically causes pre mature death (PMD) of hybrids. There has been very little of this seen this year due to warm conditions at planting and rapid emergence.
Written By: Brian Mitchem, PCT | Sunrise Research Agronomist