Phyllosticta-needle blight of Cupressaceae - Phyllosticta thujae
Symptoms / species
Impact / measures
This disease is characterized by bright yellow, later brown tips of twigs of Arborvitae or Port Orford Cedars; with more intense infestation larger parts of twigs may become brown, which mostly appears scattered (nest-wise) on the tree. On the brown to black leaves round, shining blackish fruiting bodies (asexual) of Phyllosticta thujae appear which only slightly emerge from the scale surface. In wet condition they expel whitish spore masses through a minute apical minute porus. The spores (conidia) are hyaline and characterised by an appendage.
Affected tree species
False Cypress; Juniper; Juniper cultivars; Thuja;
Phyllosticta thujae is a weak pathogen often following abiotic stress or more aggressive pathogens (e.g. Stigmina thujina) as a secondary agent.
Curative measures usually not necessary
Phyllosticta thujae: brown twig tips
Phyllosticta thujae: brown twig parts with numerous conidiomata and white spore droplets on top