By: Stephanie Karhoff OSU Extension

A female soybean cyst nematode, stained with a bright pink stain, has set up her feeding site within the soybean root. Her body will fill with eggs and become a bright white cyst visible on the soybean root. Photo: OSU Extension.
Soybean cyst nematode (SCN), Heterodera glycines, is a small roundworm that parasitizes soybean roots, stealing vital nutrients from the plant. Even if you are not seeing above-ground symptoms, SCN is likely still reducing your yield. To make matters worse, certain SCN populations are now becoming “resistant to the resistance.” In other words, a portion of the nematodes now have the capability of feeding and reproducing on soybean varieties previously thought to be resistant. The main reason for this, is that more than 95% of all SCN-resistant varieties for the past two decades included resistance gene(s) from the same breeding line, Plant Introduction (PI) 88788. Just like herbicide-resistant weeds, relying on the same SCN resistance source for the past 20 years has led to SCN populations adapting to, and overpowering the resistance. Continue reading