By Andy Luke, Field Specialist in Agronomy

A limited number of free Soybean Cyst Nematode (SCN) egg count tests are available for area farmers. The free tests, provided by a SCN Coalition grant, can be claimed by contacting the Harrison County Extension Center at (660) 425-6434.

Soybean Cyst nematodes are one of the most yield-limiting pests in Missouri soybean fields. Many commercial soybean varieties have SCN-Resistance traits, but 95% of these varieties have conferred resistance from the PI 88788 breeding line. Unfortunately, nematodes are becoming “resistant to the resistance” and are able to reproduce on PI 88788 varieties. Research from Iowa State University has shown yield decreases of up to 14 bushels per acre from SCN reproducing on PI 88788 varieties, with yield reductions much greater on non-resistant varieties.

New resistance methods are being developed, but farmers still need to manage SCN in the meantime. SCN tests (normally $25) provide the egg counts in a particular field and indicate the management strategies that a farmer should take in that field. Control measures include rotating to a non-host crop, using SCN resistant soybean varieties, and using nematode protectant seed treatments.

Sampling for SCN can be completed throughout the year, but is easiest in the fall directly after harvest. Samplers should collect 15-20 one-inch-diameter core samples, 8 inches deep, for each area of the field. The samples should be taken within the soybean row, not between rows, as the nematodes will be on the soybean roots. The samples should be mixed thoroughly and clearly marked, then stored out of the sun in a cool spot until shipping.

Collected samples will be submitted to the SCN Diagnostics Lab in Columbia. If you have any questions about SCN, or would like to claim some of the free SCN egg count tests, contact Andy Luke at (660) 425-6434.