By Shawn Brenneman Syngenta
Detecting soybean cyst nematode (SCN) is a challenge to many Ontario growers. Quite often, SCN symptoms are misdiagnosed as other production issues at the field level. Shawn Brenneman, agronomic services manager and certified crop specialist at Syngenta, offers four ways growers can detect this hidden pest in their fields.
1. Know the above-ground symptoms: The most noticeable above-ground symptom may start off as circular patches within the field where beans are stunted and yellowed. Soybean Cyst Nematode (SCN) is spread through soil movement, so symptoms may first appear at field entrances or headlands.
2. Pay attention to your yield monitor at harvest: Since many times visual symptoms may not occur, the best time to diagnose SCN is at harvest. Note areas in the field where harvest yields don’t make sense with the field’s history.
3. Visually inspect roots: In August or September, carefully dig up root masses. Gently wash the soil off roots and use a hand magnifying glass to identify the cysts, but beware of only relying on a simple visual analysis since cysts can be difficult to see and may sometimes be confused with bacterial nodules.
4. Have your soil tested: Since visual symptoms are not always evident either in the field or on the roots, the most accurate detection is to have your soil tested. After harvest is an ideal time to test for SCN since egg and cyst counts should be at their highest for the season.