Total Damage
Total damage is the percentage of kernels and pieces of kernels that are visually damaged in some way, including damage from heat, frost, insects, sprouting, disease, weather, ground, germ, and mold. Most of these types of damage result in some sort of discoloration or change in kernel texture. Damage does not include broken pieces of grain that are otherwise normal in appearance.
Mold damage is usually associated with higher moisture contents and warm temperatures during the growing season and/or during storage. There are several field molds, such as Diplodia, Aspergillus, Fusarium, and Gibberella, that can lead to mold-damaged kernels during the growing season, if the weather conditions are conducive to their development. While some fungi that produce mold damage can also produce mycotoxins, not all fungi do produce mycotoxins. Chances of mold decrease as corn is dried and cooled to lower temperatures.
Results
Average U.S. Aggregate total damage (2.6%) in 2016 was higher than 2015 (1.4%), 2014 (1.7%), and 5YA (1.2%). However, the 2016 total damage average was still below the limit for U.S. No. 1 grade (3%).
Total damage variability in the 2016 crop, as measured by the standard deviation (1.61%), was higher than 2015 (1.00%), 2014 (1.36%), and 5YA (0.97%).
The range for total damage in 2016 (0.0 to 23.1%) was higher than in 2015 (0.0 to 13.2%) and 2014 (0.0 to 17.3%).
Total damage in the 2016 samples was distributed with only 71.8% of the samples having 3% or less damaged kernels and 89.3% having 5% or less, compared to 2015 with 88% and 96%, respectively. Thus, the histogram shows a larger percentage of samples having total damage above 3% than in previous years. These samples could present an added storage risk if not adequately dried and properly aerated.
Average total damage by ECAs was 3.2% for Gulf, 1.0% for Pacific Northwest, and 2.5% for Southern Rail. The Pacific Northwest ECA had the lowest average total damage, and the Gulf ECA had the highest total damage for 2016, 2015, 2014, and 5YA.
Average total damage values in all ECAs were well below the limit for U.S. No. 2 grade (5.0%).