Connie’s Comments by Connie Strunk, Turner County Extension Educator—Agronomy  November 9, 2009

 

            Enjoying the beautiful weather last week was a welcomed change of pace for me and my family and for many, many local farmers.  It was great to see the fields alive and buzzing with harvesting equipment!  Soybeans were the focus of many the last few days.  There was even some corn being taken out.  Speaking of corn, a lot of corn in the area has been affected by mold.

            The concern we have about moldy corn is actually whether or not there is mycotoxins present in the grain.  Mycotoxin management at this stage (harvest) involves optimizing harvest and storage conditions to minimize physical damage and avoid additional mold growth.  Drying corn as quickly as possible to below 12-14% is ideal though it may be quite difficult to achieve that level of drying given the late harvest and wet weather.  Storage at cool temperature will help to slow down fungal growth in grain, and gentle handling will limit the amount of damaged grains which are a source of nutrients for fungi in storage.  Mycotoxin testing is encouraged for those producers wishing to feed the grain or silage to their livestock as high levels of mycotoxins may lead to feed refusal, sickness, or in some cases, even death.  There are several fungi that can cause ear mold problems in corn which include Aspergillus, Gibberella, Fusarium, Cladosporium, Trichoderma, Penicillium, and Diplodia. 

Cladosporium (dark green or black powdery mold that also causes black streaks on kernels), Trichoderma (dark green mold that grows on or between kernels and often covers the entire ear), and Penicllium (bluish-green to gray, mostly powdery in appearance) have been commonly observed as they are found in the air and soil.  They are known as surface contaminants and can be easily rubbed off and are generally non-toxigenic (not known to produce mycotoxins) but may increase storage losses.  As with any moldy corn the palatability of the grain may be affected.

Aspergillus (much brighter green to yellow-green color and powdery in appearance) is a major concern when it is hot and dry or received insect damage.  This fungus produces the mycotoxin aflatoxin.  This mycotoxin/mold does not seem to be a major problem this year due to our wet weather.

Diplodia (compact white mycelium between kernels beneath the husks) often, black pycnidia will form on the husks – looking like small peppery spots. No mycotoxins are produced by this fungus. Often this begins at the butt-end moving outward.

Molds to watch for this year that produce mycotoxins are:

Gibberella (red or pink color) that almost always begins at the tip of the ear but remember to look at the color and not just where you are seeing the mold.  The fungus produces the mycotoxin vomitoxin.

Fusarium (white to pink cottony mycelium between kernels and under the husks) and produces the mycotoxin fumonisin.

Gibberella and Fusarium ear rot are a common problem in wet years and can produce mycotoxins.           

If you are interested in having your corn or silage tested for mycotoxins you have a couple of options:

SDSU Plant Diagnostic Clinic

SPB 153, Box 128; Jackrabbit Drive

Brookings, SD   57007

 

SDSU Diagnostic Clinic will test for Aflatoxin, Fumonisin, Vomitoxin, and Zearlenone and they charge $ 35 for one test and $ 15 for each additional test.  It is an $ 80 charge for all four tests.  Their telephone number is 605-688-5545 and their website is http://plantsci.sdstate.edu/planthealth.

 

SDSU Analytical Services

            South Dakota State University

            SAS 133, Box 2170

            Brookings, SD   57007-1217

           

            Oscar E. Olson Biochemistry Lab Services offered include aflatoxin, fumonisin, deoxynivalenol screens for $ 35 per compound.  Their telephone number is 605-688-6171 and their website is http://anserv.sdstate.edu/.

 

NDSU Veterinary Diagnostic Laboratory

NDSU Van Es Hall

1523 Centennial Blvd

Fargo, ND 58102

 

NDSU offers a multi-mycotoxin screen at around $ 100 for a 19 toxin panel.  They test for the same four as SDSU, plus a trichotecene panel (nivalenol, T-2, etc.)  Their telephone number is 701-231-8307 and their website is http://www.vdl.ndsu.edu/vdl/services.aspx.

 

If you find yourself dealing with high moisture corn and are wondering what your options are; Steve Pohl, SDSU Structures and Environment Specialist, has outlined a few options for you:

n  If the moisture content is over 26%

n  Leave it in the field

n  High moisture corn storage (i.e. bags)

n  High Temperature drying

n  In-bin drying

n  Continuous Flow

 

n  If the moisture content is 22% to 25%

n  Leave it in the field

n  High temperature drying

 

n  If the moisture content is less than 21%

n  High temperature drying

n  Natural/low temperature drying (depending on moisture content, time of year, will be drying in spring)

 

Some things to consider when drying and storing your corn is:

n  Do not mix corn with high levels of mold damage with good corn

n  Dry down to 14% moisture content

n  Remove fines

n  Coring the Bin

n  Aerate thoroughly

And remember to follow and practice personal safety when working in and around grain bins.

SDSU has developed a website dealing with damaged grain (in this case moldy corn) which you can reach at http://sdces.sdstate.edu/weatherdamagedgrain/index.cfm. 

For more information or if you would like to receive email updates about the moldy corn situation please feel free to contact me at the Turner County Extension Office at 605-297-3112 or by email at connie.strunk@sdstate.edu.  I hope we have some more nice weather and that harvest continues without any more trouble. 

For your information:  The mycotoxin survey that I mentioned a few weeks ago is underway and I am still in need of a few samples.  If you are interested in this free assessment please feel free to contact me.  I can either come and get the samples from you (whether that is out in the field, on the farm, or at the co-op) or you could drop off your samples here at my office.  All that is required is about 5 lbs of shelled corn with a description of what field (where in the county it came from) so we can see how the mycotoxin levels play out throughout the state of South Dakota.  It would be nice if you are able to provide the variety, etc. but I will take what I can get!  Thanks in advance for your help with this survey.