In a recent blog post, University of Minnesota scientists shared research results on soybean cyst nematods in soybean seed-treated fields.

The Minnesota Soybean Research and Promotion Council funded the 2014-15 study to provide data on the potential efficacy of the seed treatment Clariva for SCN management.

One objective was to evaluate the effects of this biological nematicide and other fungicide plus insecticide treatments on soybean yield, including potential interactions with SCN host plant resistance, environment, and an insecticide plus fungicide combination.

A second objective was to determine if Clariva affects SCN reproduction.

U-M releases multi-site study on seed treatments in soybeans

Eleven locations were involved and seed tratments were evaluated on a soybean variety with PI 88788 source SCN resistance and on a susceptible variety.

Seed treatments compared were Clariva® Complete™ + Mertect® fungicidep; Clariva® Complete™; Cruiser Maxx® + Vibrance™ fungicide (an insecticide/fungicide counterpart to Clariva Complete without the Clariva); Cruiser Maxx®; or untreated seed.

According to research conducted by Extension IPM specialist Bruce Potter, nematologist Senyu Chen, Extension educator Phil Glogoza, Extension plant pathologist Dean Malvick and Extension educator Ryan Miller:

-2015 results were similar to those observed in 2014. Variety selection has an impact on yield and SCN reproduction. Resistant varieties performed better than susceptible varieties under significant SCN population pressure.

-In one of the 11 study sites last year, seed treatments yielded significantly more than untreated seed. At this site, treated seed yielded more than the untreated check and all seed treatment combinations yielded similar. The addition of Vibrance fungicide, Clariva nematicide, or Mertect fungicide did not increase yield above that of Cruiser Maxx, the base fungicide plus insecticide.

-Unlike the 2014 results, when the 2015 data was analyzed across all sites, the group of seed treatments yielded more than untreated seed, but only for the SCN resistant varieties.

-There was no yield benefit for adding the nematicide or additional fungicides over the base fungicide plus insecticide treatment.

The researchers noted that the results indicate that when deciding to use soybean seed treatments as a production input, growers should carefully evaluated them. They also reinforced the importance of preserving the effectiveness of SCN resistant varieties.