Assessment of the potential of novel Californian grapevine Trichoderma isolates to reduce colonization of fungal trunk canker pathogens and Xylella fastidiosa

Results potentially yielded <i>Trichoderma</i> isolates with some ability to limit fungal pathogens in culture, greenhouse plants, and pruned spurs in the field, and with the ability to be re-isolated after a full field season. However, these isolates were not able to consistently limit <i>Xylella fastidiosa</i> titers or Pierce's disease symptoms. Taken together, these experiments demonstrated the ability of California <i>Trichoderma</i> isolates to be deployed as locally sourced biological control agents to protect Californian vineyards as well as those in similar climates.