HARVEST TIPS FOR MOULDY CORN!
1. Prioritize your corn harvest and storage. Do not mix old crop (2017) or low DON corn 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.
2. As a general rule, harvest infected fields first BUT due to the delayed harvest conditions in the affected areas, growers should consider harvesting fields with lower ear rot disease and lower DON (test sample) instead of those fields with high DON. Mycotoxin levels have the potential to build the longer you leave the corn in the field and it is best to get the marketable corn out of the field quickly. Once corn moisture is below 18%, mould fungi growth and mycotoxin production slows down.
3. If certain areas of the field (e.g. outside rows) show high insect or bird damage, or high occurrence of moulds/DON, harvest those areas separately. Also avoid sampling from this ares when collecting a sample for mycotoxin testing. Handle and store this grain separately to prevent contamination of the cleaner grain.
4. 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.
5. 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 increases potential storage problems.
6. 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.
7. In corn silage, the acids produced during proper ensilage will stop the growth of moulds. Acidifying the grain with an additive will accelerate the process. Where there is improper fermentation, moulds could continue to produce mycotoxins and lead to higher toxin levels that could affect cattle.
For more ear mould and mycotoxin information as well as other field crop disease management issues , visit the Crop Protection Network Website or check out the following publications –