Reduce risk of mycotoxin contamination by scouting fields for ear rot

decrease font size  Resize text   increase font size       Printer-friendly version of this article Printer-friendly version of this article

 

Hail storms damaged several corn and soybean fields in parts of Iowa last week. In some areas, the corn and beans are completely lodged as a result of the storm. In other areas, leaves are significantly stripped, but the grain seems relatively undamaged. 

During the 2009 growing season, approximately one million acres of crops from Sac to Grundy Counties were damaged by a single hail storm. Most of the corn crop was at growth stage R2.  We conducted a survey to assess the impact of hail damage on grain quality (Robertson et al., 2010). We found that hail damage to kernels increased the risk of ear rot and mycotoxin contamination.

Scout for ear rot

The corn that was damaged in the hail storms last week was further along in development (growth stage R5) than the grain damaged in 2009, but it still may be at risk for ear rots and associated mycotoxin contamination. Fields that were damaged need to be scouted in the next 10 to 14 days for ear rot. If more than 10 percent of the ears in a field are moldy, the field should be scheduled for an early harvest. Check with your insurance company regarding their requirements for claims. Most companies will want to assess the field before it is harvested.

Fields that were not damaged by hail should also be scouted for ear rot, since the hot, dry weather with occasional rain that has occurred recently is favorable for Aspergillus and Fusarium ear rot development. Symptoms of Aspergillus ear rot are a powdery olive-green mold that develops on damaged kernels (Figure 1). High temperatures (80 to 100 F) and high relative humidity (85 percent) favor the growth of Aspergillus in the field. Note that the presence of Aspergillus ear rot does not necessarily indicate aflatoxin contamination. Aflatoxins are produced under certain conditions, and are most often a problem when night temperatures remain above 70 F. The U.S. Food and Drug Administration regulates aflatoxin levels in food and livestock feed. An "action level" of 20 parts per billion (ppb) for aflatoxin in corn has been established for interstate commerce.

Fusarium ear rot symptoms are characterized by white to light pink mold that usually occurs on damaged kernels (Figure 2).  High temperatures (above 77 F), drought stress before or after silking and mechanical damage favor infection and the development of Fusarium ear rot. Mycotoxins associated with this ear rot are fumonisins, and the optimum temperature for fumonisin production is 75 F (which is cooler than that for aflatoxin). Bush et al (2003) found fumonisin concentrations increased from physiological maturity, thus early harvest may help reduce the level of contamination. The U.S. Food and Drug Administration (FDA) has guidelines for safe levels of fumonisins in corn used for foods and animal feeds. Fumonisins are acutely toxic to animals (especially pigs and horses), and have been linked to increased cancer rates and other human health problems.

click image to zoom
Figure 1. Symptoms of Aspergillus ear rot are a powdery olive-green mold that develops on damaged kernels.

 

click image to zoom
Figure 2. White to light pink mold is a characteristic of Fusarium ear rot.

Source: Alison Robertson, Department of Plant Pathology and Microbiology; and Charles Hurburgh, Iowa Grain Quality Initiative

References
Bush et al.  2004.  Phytopathology 94:88-93
Robertson et al. 2010.  Agronomy Journal 103: 193-199.

 


Buyers Guide

Doyle Equipment Manufacturing Co.
Doyle Equipment Manufacturing prides themselves as being “The King of the Rotary’s” with their Direct Drive Rotary Blend Systems. With numerous setup possibilities and sizes, ranging from a  more...
A.J. Sackett Sons & Company
Sackett Blend Towers feature the H.I.M, High Intensity Mixer, the next generation of blending and coating technology which supports Precision Fertilizer Blending®. Its unique design allows  more...
R&R Manufacturing Inc.
The R&R Minuteman Blend System is the original proven performer. Fast, precise blending with a compact foot print. Significantly lower horsepower requirement. Low inload height with large  more...
Junge Control Inc.
Junge Control Inc. creates state-of-the-art product blending and measuring solutions that allow you to totally maximize operating efficiency with amazing accuracy and repeatability, superior  more...
Yargus Manufacturing
The flagship blending system for the Layco product line is the fully automated Layco DW System™. The advanced technology of the Layco DW (Declining Weight) system results in a blending  more...
Yargus Manufacturing
The LAYCOTE™ Automated Coating System provides a new level of coating accuracy for a stand-alone coating system or for coating (impregnating) in an automated blending system. The unique  more...
John Deere
The DN345 Drawn Dry Spreader can carry more than 12 tons of fertilizer and 17.5 tons of lime. Designed to operate at field speeds up to 20 MPH with full loads and the G4 spreader uniformly  more...
Force Unlimited
The Pro-Force is a multi-purpose spreader with a wider apron and steeper sides. Our Pro-Force has the most aggressive 30” spinner on the market, and is capable of spreading higher rates of  more...
BBI Spreaders
MagnaSpread 2 & MagnaSpread 3 — With BBI’s patented multi-bin technology, these spreaders operate multiple hoppers guided by independent, variable-rate technology. These models are built on  more...


Comments (0) Leave a comment 

Name
e-Mail (required)
Location

Comment:

characters left


Declining Weigh Blending System

Ranco Declining Weigh (DW) is the standard in fertilizer blending because of the speed and accuracy of the blending process. ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form