June 26, 2014, Ontario – Spraying soybeans with a foliar fungicide has not been common practice in Ontario. Over the last 10 years, there has been increased interest in applying foliar fungicides to soybeans. Many trials have been conducted in Ontario to assess the yield and seed quality benefits. Averaged across five years of trials, the average response has been 2.3 bu/ac.
Seed size and quality can be improved, especially when there is significant disease pressure. In 2012, Dr. David Hooker (University of Guelph, Ridgetown) conducted trials to evaluate the correct timing for maximum economic return. The trial results were surprising in that soybeans responded more when sprayed relatively early. An application at the R2.5 growth stage (full flower) provided more yield than at later growth stages.
June 26, 2014 By Horst Bohner OMAF