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Poster Session: Diseases of Plants - New and Emerging Diseases


Fungal diseases of Cannabis sativa in British Columbia, Canada.
G. RODRIGUEZ (1), A. Kibler (1), P. Campbell (1), Z. K. Punja (2)
(1) Agrima Botanicals, Maple Ridge, BC, Canada; (2) Simon Fraser Univ, Burnaby, BC, Canada

A number of previously unreported fungal diseases were observed in a commercial growing facility of Cannabis sativa being produced hydroponically for medicinal use in British Columbia, Canada (under approved Health Canada regulatory requirements) during 2013-2014. These included root rot caused by Pythium dissotocum and P. myriotylum and bud rot caused by Botrytis cinerea. As well, Penicillium olsonii was found colonizing dried packaged product and was recovered from air samples in the growing facility. All fungi were recovered on agar media and identified by PCR using ITS1 – ITS4 primers and nucleotide sequence comparison using BLASTn. Powdery mildew infection on leaves was identified to be caused by Golovinomyces (Erysiphe) cichoracearum by PCR. Pythium dissotocum isolates were confirmed to cause root rot by inoculation of rooted vegetatively propagated plants grown in a hydroponic system. Ten days following inoculation at 25° C, plants appeared stunted and roots were rotting and discolored. The pathogen was recovered from diseased tissues. Some isolates of F. oxysporum were found to be pathogenic and caused symptoms of root browning and rot. Freshly harvested flower buds inoculated with B. cinerea and incubated at high humidity at 25°C developed symptoms of rot and decay within 9 days and the pathogen was reisolated from inoculated tissues. Isolates of P. olsonii were frequently isolated from dried product and could negatively affect product quality.