By Rachel Vann
As growers shift to using earlier soybean planting dates as a mechanism to increase soybean yield, questions arise about the value of a fungicide seed treatment at earlier planting dates. There is a lot of data that was generated several years ago to indicate that fungicide seed treatments do not impact NC soybean yield at late May or later planting dates; investigation into the value of fungicide seed treatments at earlier planting dates is merited.
In 2019 and 2020, the Soybean Extension Program looked at the value of fungicidal seed treatments for protecting stand and yield across diverse North Carolina environments in small-plot research. This research is summarized in this video.
When the small-plot data was combined over years, maturity groups, and fungicidal seed treatments, there was often a significant protection of both stand and yield at planting dates earlier than mid-May.
The NC Extension Agents, the NC Soybean Producers Association, and the NC State Soybean Extension program have been collaborating on a new initiative (OFT) where County Agents work with their producers to run large strip-plot trials that complement data being generated from small-plots at the University. This allows our programs to capture more environments of data to determine similarities and possible differences between what is observed in small-plots.
In 2020 and 2021, the soybean OFT across the state focused on fungicide seed treatments. There was a significant protection of stand detected at many sites and significant protection of yield when you combined over the sites. Results from the OFT program in 2020 and 2021 can be found here.
Our current recommendation is for use of a fungicide seed treatment to protect stand and yield in soybean planting dates prior to mid-May. Both the small-plot data and the OFT data from the past several years drives our current recommendation. Insecticide seed treatments are not needed to protect yield in NC soybean production and should be left off the seed to save money and slow resistance in pests that impact crops where a insecticide seed treatment is needed.
Source : ncsu.edu