Rhabdocline, Swiss Needle Cast and Didymascella

Needle Disease

Rhabdocline pseudotsugae - on Douglas-fir


Lesions on needles caused by Rhabdocline

Rhabdocline apothecia

Apothecia on needles as they appear when dry.

16161602.jpg (45779 bytes)

Another slightly higher magnification of apothecia when dry.


Apothecia swell up when wet and asci will release ascospores.


Another view of the mature apothecia of Rhabdocline on needles with the apothecia swelling when moisture is present. The ascospores are released in spring causing new infections.


Phaeocryptopus gaeumannii - Swiss Needle Cast on Douglas-fir

Swiss needle cast

Infected branch from the field

Swiss needle cast

Dried Douglas-fir needles with Swiss needle cast. Perithecia (numerous small black dots) can often be seen even without a hand lens if needles are inspected closely.

16161614.jpg (34365 bytes)

Perithecia emerging from stomata on infected needles are easily seen with a hand lens.

Didymascella thujina - on Western Red Cedar

Didymascella apothecia

Needle lesions containing dark round apothecia.


Higher magnification of Didymascella and apothecia

16161603.jpg (31257 bytes)

Apothecia on lesions of western red cedar produce asci with 2 ascospores per ascus.