BELIS aims to adapt existing screening protocols for powdery mildew in pea to red clover and annual clovers (i.e. Crimson clover). While ILVO focusses on red clover and Cérience on Crimson clover, CSIC supports through their expertise with powdery mildew in pea.
Local powdery mildew isolates were collected on red and Crimson clover in 2024. While Cérience uses detached leaves to maintain the pathogen, ILVO maintains powdery mildew on live plants in a greenhouse. In 2024, Cérience tested several inoculation protocols in Crimson clover: detached leaves vs. plantlets and spraying vs. shaking powdery mildew spores. ILVO optimized a protocol to inoculate red clover plantlets through contact with infected inoculum plants in a greenhouse.
First experiments on sets of control varieties were promising, as the bio-tests reproduced similar degrees of resistance as expected in the field. In addition, results in both clover crops proved sufficiently repeatable, although further work is needed to optimize inoculum production and to reduce the variability of the results. In addition, ILVO is optimizing storage of powdery mildew isolates on in vitro cultures of red clover, which would remove the need to maintain mildew-infected plants continuously throughout the year. Upscaling from in vitro powdery mildew cultures to inoculum plants in the greenhouse will be experimented in 2025.
