Corn growers who suspect that the corn they are about to harvest contains one or more types of mold must contact their crop insurance agent before they start to harvest if they want to assure their eligibility for an indemnity payment for loss of quality on the crop.
That was the point of an advisory this week by University of Wisconsin-Madison plant pathologist Damon Smith and Paul Mitchell of the agricultural and applied economics department at the university.
They pointed out that indemnity payments for loss of quality are available through crop insurance even if the yields do not trigger a payment.
Because of the combination of heat and moisture stresses during a significant part of the 2012 growing season, Wisconsin's corn growers should be especially aware of the possibility of moldy corn for the sake of the health of their livestock and for food safety, Smith and Mitchell advised.
Elevators, ethanol plants, and other buyers of corn will be checking corn for molds before they accept it, Smith and Mitchell noted. They have already been receiving reports of corn being rejected due to mold and mycotoxins.
The two fungi that most often cause molds and mycotoxin growth in corn are the aspergillus and fusarium species, Smith and Mitchell explained.
Aspergillus species thrive at temperatures above 80 degrees, relative humidity at close to 85 percent, and grain moisture at 18-20 percent - conditions that also favor aflatoxin production and fungal growth, they indicated.
Aspergillus, which is an ear root, is ordinarily more common in states to the south of Wisconsin but environmental conditions in a significant part of Wisconsin's major corn production area this year were favorable to the disease.
Corn being stressed from drought, heat, insects, or nutrient deficiency is the most vulnerable to the ear rot, Smith and Mitchell observed.
Ear rot can lead to the production of aflatoxin, for which the U.S. Food and Drug Administration (FDA) has set maximum acceptable limits of 20 parts per billion on corn fed to dairy cattle and .5 parts per billion in milk.
Smith and Mitchell described those numbers as "extremely low levels," which indicate the importance of examining corn before or as it is being harvested and testing it for aflatoxin.
What's more likely in the Upper Midwest, however, is an outbreak of the fusarium species that infect corn kernels and produce vomitoxin and fumonisins, Smith and Mitchell point out.
The FDA's allowable upper limits for vomitoxin are five parts per million (ppm) for corn fed to cattle and chickens and one ppm for human foods.
For fumonisins, the FDA's limits range from two to four ppm for corn and corn products for human consumption and from five ppm for horses up to 100 ppm for poultry.
Smith and Mitchell suggest that corn growers should check their crop for molds both before and during harvest. But visible evidence or even lack of it, they caution, does not necessarily mean that mycotoxins are present or not.
The only valid test, Smith and Mitchell emphasize, is sending samples to a reputable testing laboratory and abiding by the results.
Citing the FDA's "do not blend" policy, this means that corn found to have high levels of aflatoxin should not be blended with uncontaminated corn in an effort to alleviate the problem, they stated.
To deal with corn with obvious mold, whether in all or part of a field, store it separately to avoid cross-contamination, harvest it as soon as possible to avoid further growth of fusarium ear mold, and avoid kernel damage because the cracks could also promote the growth of fungi, Smith and Mitchell advised.
They noted that fungal growth is not likely to occur once corn has been dried to 12 percent moisture or less.
Regarding crop insurance coverage for aflatoxin or molds, be sure to contact one's crop insurance before harvesting, storing, or selling the corn, Smith and Mitchell stressed.
Crop insurance payments would be based on the loss of value of the crop due to contamination with aflatoxin or fungi molds.
Once the crop insurance agent is informed of the potential problem, he or she will direct the grower on how to proceed with the collection of grain samples and about how many samples to collect, Smith and Mitchell explained.
In many cases, growers will also be asked to leave several rows of corn stand until the assigned crop loss adjuster can what indemnity is warranted.
Growers need to be patient on the latter point because the crop insurance system has been overwhelmed with claims this year (the crop insurance industry has already paid more $1.6 billion for losses on this year's crops), Smith and Mitchell suggest.
They add, however, that one's crop insurance agent will be able to tell clients how to proceed on confirming suspected aflatoxin contamination in order to obtain any payments that are due as a result.
For more information, contact the local county Extension Service agriculture or crops agent or refer to fact sheets on aflatoxin from the Risk Management Agency of the U.S. Department of Agriculture.
The Web sites are http://www.rma.usda.gov/fields/mn_rso/2012/2012aflatoxin.pdf for aflatoxin testing in Wisconsin, Minnesota, and Iowa and http://www.rma.usda.gov/pubs/rme/2012aflatoxinfs.pdf for crop loss adjustment procedures for aflatoxin.