SoybeanCystNematode GregTylka IowaStateUniversity

Soybean cyst nematode

Description: Roundworm, about 1⁄25" long. Females are usually swollen and can be seen with the naked eye. Yellow to white in color. Larvae are less than 1⁄64" long. Eggs are contained in dead females, which are brown and lemon-shaped and appear as cysts on roots.

Timing of damage: V2 to R6

Type of damage:  Plants will appear yellowed and stunted, usually in patches throughout the field.

Scouting: Dig up stunted plants and wash soil off roots by placing in a bucket of water. Check for female nematodes on roots. Then take a soil sample and send to a nematology lab.

Economic threshold:  Varies. Ask a nematology lab or local Extension office for guidelines.

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