Keithia Thujina Needle Blight
Keithia thujina needle blight
Common name
Keithia thujina needle blight
Thuja blight
Needle blight
Needle scorch
Keithia disease
Cedar leaf blight
Causal agent
It is a fungal disease caused by a pathogen of the genus Didymascella. It mainly affects the thuja species, especially western red cedar. Lower branches show more damage compared to higher, younger branches on trees.
Scientific name
Didymascella thujina
Symptoms & Signs
The first sign of this fungal disease is the yellowing or browning of the scales. Large, black fruiting bodies are also seen on the scales, which eventually fall off once the spores are released. After the fruiting bodies fall, the leaves show a hole in their place. In case of severe infection, young shoots and seedlings can die.
Transmission
Fruiting bodies produce spores in the summer and release them in the spring. The spores travel to other plants nearby through wind, water, or infected tools and hands. Wet, warm weather conditions favor the spread of keithia thujna needle blight.
Time of concern
Late spring to summer
Common hosts
Thuja