There are 26 fungal species that can create problems for growers. Fungal pathogens such as Botryosphaeria, Ceratocystis, Diaporthe, Eutypa, and Phytophthora cause gumming and dieback in trees. Florent Trouillas, UCCE plant pathology specialist at the Kearney Agriculture Research and Education Center, provided insight on the issue during a presentation at The Almond Conference last year.
“Having the right diagnostic is really critical to adopt the best management practice for the specific pathogen,” said Trouillas. “In the field, you’ll find that there is confusion among our PCA clientele, our grower clientele…while you think it’s Phytophthora, you will want to do a Mefenoxam, or phosphites applications. But if you’re dealing with something else, then you’re sort of throwing your money out there which is not going to be resulting in any results if you’re not targeting the right species.”
There are some visual cues that can indicate what kind of pathogen a tree is infected with. But some fungal pathogens can present very similar symptoms. To be sure, a molecular diagnostic that has been developed with 23 species-specific primers can help more accurately identify canker pathogens in about a 24-hour period. While there are no cures for canker diseases, there are preventative actions that can help to limit the risk of infection. Trouillas said they evaluated several treatment options in field trials.
“Among our best products was actually Topsin M, which is Thiophanate-methyl, a chemical fungicide that worked great against the broad spectrum of fungal pathogens,” Trouillas explained. “Finally, we looked at biocontrol agents and, in that case, we looked particularly at a product with a Trichoderma biocontrol agent which is a natural fungus that’s there to colonize the wound naturally. So, the Trichoderma product such as the Vintec product, worked as great as Topsin to protect pruning wounds.”
You can learn more about important industry topics such as this at this year’s Almond Conference, December 6-8 in Sacramento.
Listen to Trouillas’ interview below.