Several questions are circulating around this year in regards to ear molds/kernel rots and potential for alfatoxin production in drought stressed fields. Here are a few details describing the specifics pertaining to aflatoxins.
Aflatoxins are a subgroup within a larger more general group called “mycotoxins”. Several ear rots and storage molds which occur every year to some degree are capable of producing mycotoxins. The term “mycotoxins” refers to “toxic chemicals” in a broad general spectrum including aflatoxins, fumonisins, tricothecenes, and zearalenone, some of which are much more problematic than others. Just because an ear and/or kernel mold is visually present does not necessarily confirm the presence of a mycotoxin or more specifically aflatoxin. Aflatoxins are a specific group of mycotoxins that get significant attention due to their potential to be relatively toxic to livestock and humans at varied levels. The specific B1 aflatoxin is also a known potent carcinogen which especially draws attention for regulation. Aflatoxins are produced by at least two species of Aspergillus. This kernel/ear mold is recognized by its somewhat olive green color. Although the presence of the mold indicates a higher risk of aflatoxin production, aflatoxins are not automatically produced when grain becomes moldy.
Environmental conditions will dictate if and at what level aflatoxins are produced. Problems associated with Aspergillus and aflatoxins are most common in hot, dry years (I think the summer of 2012 would fit that description). Fungi survive in plant residue from prior years. The fungi does best in corn from silking through grain fill when drought conditions are present during hot days and warm nights. The spores are carried by the wind and can enter the ears through injury caused by insect feeding, hail, drought, early frost and high wind which help to expose kernels to the fungus. In summary, if Aspergillus is readily evident within a field, aflatoxin production is definitely more likely considering the conditions we had this year. Those fields under high suspicion should likely be evaluated and managed separately. The following are some steps that can be taken to manage or reduce aflatoxins in grain:
1) Control ear-attacking insects.
2) Scout. Indentify early. If present, early harvest and drying of grain can help reduce further development.
3) Adjust combine to minimize kernel damage.
4) Clean grain bins and handling equipment.
5) Dry moldy corn immediately to 15% or less moisture when storing in the short term. Long term storage is not suggested.
6) Cool grain after drying and maintain at 35-40 degrees F through winter.
7) Control storage bin insects.
8) Check bins regularly.
Fig. 5.7 Yellow-green powdery growth of Aspergillus flavus on a corn rootworm-damaged corn ear can produce aflatoxins. Courtesy of Alison Robertson, Iowa State University.
The FDA has suggested recent exemptions to the long-standing action level of 20 ppb. They are as follows:
Human food and milk <0.5 ppb
Corn of unknown destination <20 ppb
Young animals <20 ppb
Dairy cattle <20 ppb
Breeding cattle, swine, and mature poultry <100 ppb
Finishing swine <200 ppb
Finishing cattle <300 ppb
Elevators will likely have their own testing protocols as well as tolerance levels depending on where the grain is being channeled to for end use.
Sources: Iowa State University
Hoegemeyer Hybrids Agronomy
Hopefully aflatoxins will not be a problem in your fields but be prepared and have a plan of action if you have concerns. If you have further questions, contact your local Hoegemeyer Agronomist of District Sales Manager.
, Ryan Spurgeon
Aflatoxin, Aflatoxins, Andy Kwapnioski, Corn, Disease, Drought and Aflatoxins, Grains, Management, Ryan Spurgeon
If these warm temperatures are getting you anxious to plant corn, try to ease this temptation by planting a different crop such as spring oats. Oats can be planted as soon as the soil thaws enough to get the seed .5 to 1 inch into the ground, typically from late February to the end of March with the sweet spot being around the 15th of March. This cover/forage can provide your operation with many opportunities to make your farm more profitable during this slow time of the year. A good stand of spring cover/forage crop like oats can out-compete over wintering and emerging annual weeds, and the residue created can help prevent evaporation from the soil during the growing season. Planting oats extends the overall time for live plants to be growing in a field promoting soil microbial development and increases soil health and productivity.
Finally, spring planted oats provide forage for livestock before your cash crop is planted and/or high quality hay with total digestible nutrients (TDN) of 56 percent and 10 percent protein when harvested at late boot and early head stages. Soybeans have been successfully planted into live oats and rye two feet tall, and then sprayed after soybeans emerge and produce their first trifoliate leaf. These beans typically out-yield their counterparts planted into a tilled field, and this is more pronounced in dryer years. You probably have already heard the cover crop buzz, and planting spring oats is another opportunity to try a cover /forage on your farm.
Spring oat cover crop check list:
- Check labels of past herbicide applications (oats are sensitive to triazine herbicides).
- Seeding: 60-110 lb/A(more if grazing), Fertilizer: 50-75 lb/A (Silage/Hay: 75-125 lb/A).
* soil test N recommended (less N may be needed)
- Planting oat no-till works good but more vigorous stands are found in tilled fields.
- Kill oats once beans emerge and produce trifoliate leaf.
Andy Kwapnioski, Cover Crops, Forage, Spring Oats, Weed Management
(Hoegemeyer Hybrids is pleased to be able to present this guest blog column from Mark Pearson, host of the nationally syndicated public TV program “Market to Market.” Mr. Pearson will be the keynote speaker at Hoegemeyer Homecoming Field Day Thursday, August 11, 2011, at 1:30 p.m.)
I am really looking forward to being part of the big Hoegemeyer Homecoming gathering in August!
The volatility in the grain and livestock markets will continue to play havoc with our profitability. Biofuels, feed demand, government debt, energy and national security are going to play even larger roles. Is our U.S. economy recovering? What will that portend for the ag sector? Who are all these people joining the middle-class? What are China's plans?
Needless to say, it will be a packed 90-minutes! Oh yeah, and there will be some humor, too.
Here's what we know today: Demand for everything we produce is growing dramatically. People around the world want meat, milk and eggs. They also want to drive cars, not bikes.
Folks in North Africa and the Middle East are frustrated by lack of economic development. Regime change is the word of the day, it's happened in Egypt. Syria, Algeria and even Libya are not far behind. More turmoil within a stone's throw of the Straits of Hormuz, where 40 percent of the world's oil must transit, will give us plenty of volatility in the energy sector, and all related commodities.
Bottom line, the ag sector needs to produce. We need to give the world the food and fuel it needs, and we need to include a "comfortable" margin of wheat, corn and beans. We also need to continue to see worldwide ag production. The United States cannot meet the demand alone. Demand for soybean meal at this point is unquenchable!
We are going to talk a lot more about all these issues, and how it affects your profitability in this exciting and dramatic period of agricultural demand!
See you in Hooper August 11!
Grain Livestock Biofuel Energy