Improving the management of sclerotinia stem rot of canola using fungicides and better risk assessment tools

Project Summary

Purpose

The main objective is to improve management practices for Sclerotinia sclerotiorum by developing a better understanding of the relationship between inoculum availability and environmental conditions before and during flowering, and how this impacts stem rot risk and fungicide response. Researchers are looking at factors (seeding rate) that influence crop development, as well as variability in flowering and the resulting fungicide efficacy at different canola growth stages. They will also evaluate fungicide efficacy when applied as a single early application or as dual applications at different flowering stages, and will refine the use of qPCR analysis and investigate the use of spore traps to assess inoculum load before and during flowering.

Progress

Conditions in 2019 were favourable for stem rot. In general, final stem rot levels generally reflected spore loads as well as relative humidity and temperature conditions. Where fungicide responses occurred, better efficacy generally reflected peak spore loads and the occurrence of favourable weather conditions. Unfortunately, in 2020 the fungicide trial experiments were postponed due to COVID-19 and will be conducted during the summer of 2022, while the 2021 field season should progress as normal.  However, Eleanor McBain was able to continue her M.Sc. project work in the Fort Saskatchewan and Legal region of Alberta in 2020. Preliminary results indicated lower spore loads and lower disease levels, which contrasted with higher spore loads and disease in 2019.