John owns a 1,000 acre farm near Morinville, Alta., where he grows wheat and canola. Mid-June of 2012 he called me to talk about some concerns he had with the health of his wheat crop. He noticed his crop was uneven with stunted and wilting plants. He said the smaller plants in the affected field were setting fewer tillers, and they were paler in colour than the healthier-looking plants. He also noted that his other two wheat fields looked healthy and did not appear to be affected.
As I approached the field, I noticed that overall it looked unhealthy. The wheat plants did indeed vary in their sizes and colour throughout the field, and many of them were leaning to the side as if nothing was holding them up. When I examined the root structures of both a healthy and unhealthy plant, I found the unhealthy plant had hardly any root structure while the healthy plant had a typical root system for a wheat tiller.
However, what allowed me to solve this case was I noticed the seed coat of the healthy plant had been coated with a seed treatment while the unhealthy plant had virtually no seed treatment coverage.
Further questioning revealed that John had treated the seed himself with fungicide using a seed treater.
The seed treatment John applied to his seed is often used to control diseases affecting wheat, oats and barley, as well as to help suppress seed- and soil-borne seed and seedling diseases, such as true loose smut, early-season Septoria disease complex, early-season Rhizoctonia root rot and Pythium.
There were two other fields that had been treated at the same rate of 10 litres per 120 bushels of wheat; however, they were treated on different days. It was plausible that a setting had been changed on the flow of seed through the seed treater, and it was not able to maintain proper coverage. Although the same rate was used on all of the wheat seed, uneven application meant that some of the seeds did not receive the required amount of product to provide effective control. At the time, John had not noticed the rate of seed flow through the seed treater.
Unfortunately, there was no solution to the problem in John’s wheat field as the damage had already been done. Although the field still produced a crop, the wheat plants experienced more disease and yield was compromised when compared with those of the other two fields where the seed had been properly treated.
It may seem costly to treat seed. However, it is an important tool in the production of disease-free, high-yielding crops. Taking the time to ensure proper seed treatment coverage will go a long way in the realization of the full economic value of your crop. †