Strip trial data shows effect of soybean seed treatment

COLUMBIA, Mo. — Soybean seed treatment provided a bump in yield but did not show much effect on soybean cyst nematode (SCN) egg counts in 2017 and 2018 data from the University of Missouri Strip Trial Program.

As part of the trial, MU researchers studied the impact of ILeVO seed treatment on SCN egg counts and yield. They conducted trials in 19 locations in 2017 and 10 locations in 2018, according to an Extension news release.

MU Extension plant pathologist Kaitlyn Bissonnette says initial data shows that ILeVO did not consistently reduce SCN egg counts and in some cases slightly increased egg counts.

“In the strip trials, we observed quite a bit of variability in SCN egg counts even within a field and between treatments,” Bissonnette says.

The data is consistent with small-plot research at Iowa State University and results reported by the Iowa Soybean Association OnFarm Network.

Researchers took soil samples the first week of planting and the week of harvest to measure the number of SCN eggs in the soil.

In another crop-protection strip trial, Bissonnette looked at whether a fungicide applied to soybeans at the R3 growth stage effectively reduced foliar disease. The dry 2018 growing season contributed to the low levels of foliar disease.

Septoria brown spot was observed at all 10 locations and frogeye leaf spot was observed at eight locations, but levels of both diseases were low. At one location where a susceptible variety of soybean was planted, frogeye leaf spot severity was greater in the untreated strips than the fungicide-treated strips.

At all locations, researchers found no yield difference between treated and untreated strips.