Free Soybean Cyst Nematode Type Testing Program Available in Michigan

The soybean cyst nematode (SCN) Type Test will help you increase soybean yields by ensuring you select the best source of SCN resistance for your SCN-infested fields.

The soybean cyst nematode (SCN) is the most damaging soybean pest in Michigan. Because of this, the Michigan Soybean Promotion Committee has offered free standard SCN analyses since 1996 to help producers identify SCN-infested fields and develop management strategies.

 The standard SCN analysis is the best way to determine the SCN population level in a given field. However, it does not identify the type of SCN population present. This information is becoming increasingly important as SCN populations have begun to shift in Michigan. Michigan State University Extension  recommends producers monitor SCN population shifts so that they can select varieties containing the correct source of SCN resistance for the SCN populations in their fields.

Michigan State University offers an SCN Type Test which measures the ability of the SCN population in your soil to develop on a susceptible variety and the three commercially available sources of SCN resistance: PI88788, PI548402 (Peking) and PI437654 (CystX or Hartwig).

The Michigan Soybean Promotion Committee is offering free SCN Type Testing in addition to the standard SCN analysis to Michigan soybean producers. Additional information on SCN Type Testing is available online at: http://www.pestid.msu.edu/

The SCN Type Test results are easy to interpret. A female index (FI) is calculated by dividing the number of SCN females that developed on each of the sources of resistance by those found on the susceptible variety and multiplying by 100 to get a percentage. If the FI is at least 10% for varieties with Peking resistance, the SCN population is type 1. If the FI is at least 10% on PI88788, the population is type 2. If the FI is 10% or more on CystX or Hartwig, the population is a type 4. If the FI is 10% or greater on more than one source of resistance, the types are listed and separated by periods. SCN populations are further characterized by the level of reproduction on each of the sources of resistance (Table 1).

Table 1. Interpretation of SCN Type Test Results

Female Index (FI)

Relative SCN Resistance Level

< 10%

Resistant

10 to 30%

Moderately resistant

30 to 60%

Moderately susceptible

> 60%

Susceptible

 Michigan soybean producers should submit soil samples for SCN type testing from SCN infested fields under the following conditions:

  • Soybean yields have been declining despite the use of SCN-resistant varieties
  • At least once every five years in every field where soybeans are grown

There is also a place on the standard SCN analysis submittal form for producers to indicate if they want SCN Type Tests run on samples containing more than 2,500 SCN eggs. Indicating yes on the form will not delay the standard SCN analysis results even though the SCN Type Test takes at least 35 days to complete. Please provide an e-mail address or phone number so you can be notified of the standard test results, a complete report will not be sent until the SCN Type Test is completed.

Always remember to collect one to two quarts of soil for the standard SCN analysis if an SCN Type Test is desired. If not, a pint of soil is adequate for the standard test. Please send all SCN samples to the following address:

MSU Diagnostic Services
578 Wilson Rd, Room 107
MichiganStateUniversity
East Lansing, MI48824-6469

Utilizing the free SCN Type Test offered by the Michigan Soybean Promotion Committee will help you select the best source of SCN resistance for your SCN-infested fields.

This article was produced by the SMaRT project (Soybean Management and Research Technology). The SMaRT project was developed to help Michigan producers increase soybean yields and farm profitability. SMaRT is a partnership between Michigan State University Extension and the Michigan Soybean Checkoff program.

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