First report of Pythium schmitthenneri on olive trees and in Morocco

In a grove in north-eastern Morocco in 2020, severe root rot and crown rot symptoms were noticed on olive trees (Olea europaea). Pythium schmitthenneri was identified as the pathogen based on conidia morphology and cytochrome oxidase subunit II (COXII) gene sequence analysis. Koch's postulates were verified by re-isolation of the fungus P. schmitthenneri from artificially inoculated olive seedlings after a pathogenicity test. This is the first time P. schmitthenneri has been identified as the cause of olive tree root and crown rot in Morocco.

Automated summary

Severe root rot and crown rot symptoms were observed on olive trees in a grove in northeastern Morocco in 2020. The pathogen responsible, Pythium schmitthenneri, was identified through conidia morphology and gene sequence analysis. Koch's postulates were confirmed through re-isolation of the fungus from artificially inoculated olive seedlings. This is the first report of P. schmitthenneri causing root and crown rot in olive trees in Morocco.