First report of Thielaviopsis basicola on Daphnecneorum

Abstract

A previously undescribed fungal disease, coined daphne sudden death syndrome (DSDS), was reported on Daphne cneorum from several nurseries and research centres in British Columbia, Canada. Diseased and healthy plants were obtained from several sources, and from these plants, the following fungi were isolated: Fusarium roseum, Fusarium oxysporum, Trichoderma sp., Aspergillus sp., and Thielaviopsis basicola. However, only Thielaviopsis basicola was recovered from every diseased plant while being absent from healthy plants. All isolated fungi were grown as pure cultures and individually inoculated, via topical application of a spore suspension, to the roots of either healthy, 2-year-old D. cneorum plants or healthy rooted plantlets grown in vitro. The Thielaviopsis basicola isolate was the only recovered fungus to induce symptoms that matched those previously observed from DSDS-infected plants. Therefore, we conclude that Thielaviopsis basicola is the causal agent of DSDS.

Keywords:

• Daphne cneorum 'Ruby Glow'
• daphne sudden death syndrome
• garland flower
• mad daphne disease
• root pathogen
• Chalara elegans