In the fourteen years that Dr. Sam Markell has been in his current position as extension plant pathologist at North Dakota State University, he has not only seen an expansion in soybean acreage, but also in soybean diseases and nematodes. Well, one nematode in particular. You’re going to hear Sam mention several diseases throughout the course of today’s conversation. You’re also going to get a fascinating conversation about why knowing your soils can help you manage soil pathogens, and a science-fiction like idea of fighting these diseases in the future.

For the most part we’re going to focus on two of the main problems: soybean cyst nematode and sudden death syndrome. Dr. Markell has observed the adaptation of the nematode causing soybean cyst disease to previous varieties that were once resistant. The same genetic resistance was used in common soybean varieties and after years of efficacy it is now showing susceptibility in specific locations. However, that susceptibility is likely to spread.

“Particularly with pathogens, they're microscopic for the most part so you can assume they're light. If you can see soil particles blown around, you need to assume that you're blowing pathogens around.” - Dr. Sam Markell

Sudden death syndrome is caused by a fungus and can also be spread through soil transfer. While the fungus will not leave the roots they infect they will produce a toxin that affects the entire plant. Dr. Markell shares that seed and variety selection is one of the most crucial management strategies for disease management. He also highlights the efficacy of extending crop rotations to reduce the pathogen load in the soil.

“We know for sure that we will always have invasive pathogens. We also know that the pathogens we do have, they are going to adapt. They are going to change. They're going to evolve. They'll mutate, they'll increase in different ways…. We can handle them really poorly or we can handle them really well.” - Dr. Sam Markell

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Soil Sense Podcast is hosted by Tim Hammerich of the Future of Agriculture Podcast.