Does Corn have an expiry date?

Many of us would not drink milk past the expiry date, maybe on a dare but even then many of you are probably a little uneasy with just the thought of this. As corn harvest is slowed down due to weather or full elevators I get that same uneasy feeling I get thinking of drinking spoiled milk. In 2010 we planted our corn early and had great heat and rains throughout the summer in much of the corn producing areas of Ontario and Quebec and yet we are somewhat surprised that the standability is starting to weaken. Could it be that we have went past the expiry date on corn stalks and roots?
I would say yes. Current moisture levels are below 20% and the corn was fully mature (black layer) over a month ago, so the plant has been dead for a while. Dead plant material rots. If you add moisture (heavy dews, frequent rains even frost) it rots faster, plain and simple. Add high winds and rotting stalks break. One of the main differences I see in traveling from a Western corn area (mid west US) to an Eastern corn area is the higher level of moisture and therefore rot organisms that the corn plant must survive. In the East our expiry date is less than the West. Also, how the plants partitions its energy resources (sugars) – yield or plant health affects the expiry date of corn. If every plant only has one 2 gallon pail of energy to use where is it going to use it (ex. 1/2 gallon for stalks, 1/2 gallon for roots and 1 gallon for grain) each hybrid is different on how it partitions its 2 gallon bucket. Generally, the very high yielding genetics put more of its bucket into grain and the stalks and roots may run out as we go later into the season (shorter expiry date). Average yield with consistent standability may use more of its 2 gallon bucket for stalks and roots and therefore stand longer but yield less (long expiry date).

So what do I do as a grower? Harvest your short expiry date hybrids early to maximize the yield of those hybrids. This fall select a portfolio corn genetics that have long and short expiry dates.

Have a safe harvest.


Harvest Tips for Mouldy Corn

Some area’s in Ontario are seeing a higher levels of ear mould this year. I have included the harvest tips used in previous years.

First using the inserted picture determine if you are at risk. A quick method of determining if you are at risk includes scouting 100 plants from the field (5 areas of 20 ears each). Fields with 25 % of the ears having mould growth should be harvested sooner rather
than later.

A) Prioritize your corn harvest and storage. If producers have 2009 crop corn still left on the farm it is important to not mix it with potentially mouldy corn from this harvest. Livestock producers, especially hog, will want to scout fields, sample and test for mycotoxins in order to store their cleanest corn for feeding purposes. Cash croppers are advised that the same process of keeping clean corn segregated from mouldy corn may result in some increased marketing opportunities over the upcoming months.
B) As a general rule, harvest infected fields early. Mycotoxin levels have the potential to build the longer you leave the corn in the field. Once corn moisture is below 18%, mould fungi become dormant and cease to produce mycotoxins.
C) High temperature drying stops mould growth and mycotoxin production but does not reduce mycotoxins already present. Optimum temperature for mould growth is 28oC; mould stops growing at >30 degrees C. Quick drying is preferred over low heat drying. Be wary of low temperature in bin dryers for mouldy corn and be sure proper ventilation requirements are met for storing dry corn.
D) Leave tip kernels attached to the cob if possible by running the combine at full capacity with concave settings open and cylinder speed set low. Screens on the bottom of the grain elevator, the bottom of the return elevator and on the unload auger will also help screen out the fines.
E) Set the combine to provide high levels of wind to blow out the lighter infected kernels. Gibberella ear rot infection results in kernel damage. As noted above, cob pieces and the fines (kernel tips and red dog) contain higher concentrations. Be careful combine
adjustments do not result in kernel damage. The sample could be downgraded and increase potential storage problems.
F) Additional post-combine grain cleaning with rotary screen type cleaners has been shown to be effective in reducing mycotoxin levels in the remaining grain. This
method has the most significant impact on grain samples with low to moderate mycotoxin levels.

Check your fields before you harvest and develop a plan if you do see ear mould infection. Have a safe harvest.

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