The Van Trump Report

Following Harvest Time to Scout Those Fields… October is Soybean Cyst Nematode Action Month

Soybean cyst nematode is one of agriculture’s most destructive pests, capable of causing significant yield loss, costing soybean farmers more than $1.5 billion every year. One of the worst things about SYN is that they do their damage before most growers even know they have an infestation. Early detection is the best tool to manage the pest and prevent its spread. To help farmers defend against the devastating pest, BASF Agricultural Solutions and The SCN Coalition have designated October as “Soybean Cyst Nematode Action Month.”

Fall is the ideal time of year to test your fields for soybean cyst nematode (SCN) as there is likely to be a higher and more detectable occurrence of SCN in the fall following soybean harvest. Considered the number one yield robbing soybean pathogen in North America, research shows SCN can cause over -40% yield loss in some cases. Unfortunately, the nematode is easily overlooked as it often does not cause obvious aboveground symptoms for several years, even as it begins to immediately reduce yields.

BASF Technical Services Representative Troy Bauer says, “The goal of SCN Action Month is to educate and encourage growers to take a proactive approach to SCN management. Testing their soil for nematodes is the best option to uncover the threat for yield loss,” says Bauer. BASF is giving away a free soil test kit to the first 500 growers to request one by Oct. 31 at the promo website HERE. If growers test their soil and mail it to the BASF-approved lab postmarked by November 15, BASF will also cover the costs of one soil sample lab test.

SCN numbers are low when the nematode is first introduced into a field, but those numbers increase steadily if left unmanaged. SCN is caused by the nematode Heterodera glycines, which has three main life cycle stages. The cycle starts in the spring when temperature and moisture levels are adequate for egg hatch to release the juvenile nematode. Once a juvenile penetrates a soybean root, it moves through the root to the vascular tissue. In the vascular tissue the nematode establishes a feeding site. It then continues to feed and swell and eventually the females burst through the root tissue. Cysts on roots can contain hundreds of eggs that are eventually released into the soil and can remain viable for years until a suitable host plant is found. Infection by SCN can also potentially increase other soil-borne soybean diseases such as brown stem rot, sudden death syndrome, and Fusarium root rot.

Gregory Tylka and Christopher Marett, nematologists at Iowa State University, found that between 1996 and 2016, SCN caused estimated yield losses of nearly $32 billion, which works out to more than $1.5 billion annually. The latest data shows SCN was found in 55 new counties in 11 U.S. states and 24 new rural municipalities in Canada between 2017 and 2020. Experts also warn that if the pest hasn’t spread to your area yet, it’s just a matter of time before it does. “The continuing spread of SCN is alarming, but not surprising,” said Tylka. “Anything that moves soil can move the nematode, including wind, water, and farm machinery.” Tylka urges all soybean farmers to test their fields for the presence of SCN by soil sampling before every second or third soybean crop, even if the pathogen has never been found in their fields before. Learn more about SCN and find additional resources for managing the pest at the Soybean Cyst Nematode Coalition HERE.  (Sources: Iowa State University, SCN Coalition, BASF)

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