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Field evaluation of SCN-resistant soybean varieties

Investigators: Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett
Funding: Iowa Soybean Association, seed company fees

An effective and affordable way to manage SCN is to grow resistant soybean varieties. SCN-resistant soybean varieties suppress SCN reproduction, reducing the yield loss caused by damage from nematode feeding. SCN resistance preserves the yield of soybean varieties growing in SCN-infested fields.

Field evaluation of SCN management products

Investigators: Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett, David Soh
Funding: Iowa Soybean Association, company fees

Each year, one or more foliar-, seed-, or soil-applied products are advertised for use in managing SCN. Growers and agribusinesses in Iowa turn to Iowa State University for an unbiased evaluation of the effect of these products on SCN populations and soybean yield.

Studies of the interactions of SCN with brown stem rot of soybean

Investigators: Gregory L. Tylka, Girma Tabor, Charlotte Bronson, David Soh
Funding: North Central Soybean Research Program, Iowa Soybean Association

Iowa fields are commonly infested with both SCN and brown stem rot (BSR). In the early 1990s, researchers observed that BSR-resistant soybean varieties had much greater than expected levels of BSR disease in fields infested with SCN than in those without SCN.

Studies of the interactions of SCN with the soybean aphid

Investigators: Gregory L. Tylka, Matthew E. O’Neal, Felicitas Avendano
Funding: Iowa Soybean Association

The soybean aphid, Aphis glycines, was first discovered feeding on soybeans in Iowa and other Midwestern states in 2000. Since then, it has spread throughout the state and region. Currently, soybean aphids are found in every county in Iowa and the insect has become a serious yield-reducing pest of soybeans in the state.

Distribution of SCN in Iowa and occurrence of HG types

Investigator: Gregory L. Tylka, David Soh
Funding: Iowa Soybean Association

SCN was first discovered in Iowa in Winnebago County, in extreme north central Iowa, in 1978. Currently, the nematode is known to exist in 97 of 99 Iowa counties (all except Allamakee and Ida Counties). A random survey of Iowa was conducted in 1995-1996 to better define the distribution of SCN in the state. SCN was found in 74% of Iowa fields sampled in that survey. SCN was found much less frequently in no-till fields than in tilled fields sampled in the survey.