By Tom Collins
This year’s weather has led to ideal conditions for sudden death syndrome (SDS) in soybeans, but Eastern Ontario farmers haven’t been as hard hit as their Western Ontario brethren.
The number of cases in Eastern Ontario is up this year, said independent agronomist Gilles Quesnel, but overall, the number of fields with the disease is still low for the plant disease that has been in the area for years.
The disease thrived in cool wet conditions during planting, followed by hot dry stress conditions and the frequent and consistent rains from mid-July until early September.
SDS is a root rot disease where symptoms do not show up until the mid-pod reproductive stage, and by then, it is too late to do anything. The first symptom is a distinct yellow speckling or spotting between the veins on the leaves. Eventually, the parts of the leaf between the veins turn brown and fall out. The next symptom is plant death.
Yield losses are varied, depending on the severity of the disease.
Quesnel said once a field has the disease, it increases the chances the field will get SDS again in the future with the right conditions. He added root diseases in soybeans are usually a problem on heavier soils such as clay, but he said to date, SDS has been more prominent on the lighter soils.
There were 2.22 million bushels of Ontario soybeans were lost to SDS in 2015, and OMAFRA’s field crops pathologist Albert Tenuta expects that number to be much higher this year.
OMAFRA’s soybean specialist Horst Bohner said farmers shouldn’t necessarily worry about SDS.
“It’s like any of the diseases,” he said. “It’s all a question of severity and incidence. A little bit of sudden death doesn’t scare me at all. A plant here or there or a pocket here or there. That’s just par for the game. It’s when you get these fields that are heavily excessive, that’s when you start to get into trouble.”