The 2013 growing season was characterized by weather extremes, leading to crop stress on corn during the grain fill period and causing delayed maturity. This has created favorable conditions for classic corn ear molds to develop. DuPont Pioneer agronomists warn that the environment will become increasingly ideal for ear molds if the weather brings cooler temperatures and periodic rains as this year's crop heads into harvest. In addition, drought stress and insect injury to the crop provide an avenue for fungi to enter, causing ear molds to establish and spread.
"The carryover of ear mold inoculum from last year's drought environment is likely minimal; however, growers with a history of molds should carefully scout their fields," says Bill Dolezal, DuPont Pioneer plant pathology researcher. "While not significant, we have heard reports of ear molds in Indiana and Illinois, as well as Missouri and Tennessee, this year. Ear molds reduce yield potential, grain quality and feed value."
Now is time to scout fields, identify molds and determine if mycotoxins are present
While scouting, it's important to identify molds and determine if mycotoxins are present. If mold presence is greater than 10,000 cfu/gram and is of the Aspergillus, Fusarium, Gibberella or Penicillium strains, a mycotoxin screening should be completed. Many crop insurance policies require that you contact your crop insurance agent as samples must be pulled from the field by a loss adjuster prior to the grain being placed in storage. The representative sample must be sent to university plant pathology labs for proper mycotoxin screening and identification.~~~PAGE_BREAK_HERE~~~
If 10% or more of the ears in the field have a significant amount of mold present on greater than 25% of the ear, harvest as soon as possible, Dolezal advises. The best way to prevent further growth and toxin development is to harvest at or above 20% moisture content and then dry the corn to 15% moisture or less.
When harvesting, be sure to adjust your combine to minimize kernel damage and to remove the lightest kernels. Broken kernels often have a higher likelihood of toxin development.
Dry grain to less than 15% moisture and cool it to below 50 degrees F as quickly as possible following harvest
Proper grain drying and storage are critical to minimize further proliferation of existing molds. Grain should be dried to less than 15% moisture and cooled below 50 degrees F as quickly as possible following harvest. Prior to storage, clean grain to remove any infected kernels, cobs and fines.
If possible, store infected grain separately to avoid putting the entire bin at risk for contamination. Grain should be stored in cool temperatures, preferably around 30 degrees F. To maintain condition, regularly monitor and check grain in storage for temperature, moisture and insects. After handling infected grain, thoroughly clean drying bins and equipment to avoid further contamination.
Looking ahead to next year, Pioneer agronomists provide several tips to manage and decrease the likelihood of corn ear molds. Consider planting regionally adapted hybrids, such as those in the Optimum® AcreMax® product line-up; which offers many hybrid choices with strong traits for above-ground insect protection to help reduce damaged kernels and fungal-spore entry points. Implementing a balanced fertility program, designed for optimum yields, is also beneficial. Crop rotation and residue management can provide substantial disease control as well. For additional management tips, contact your local Pioneer sales professional or visit the Pioneer website.