Phytophthora Root Rot and Stem Canker Found on Nordmann and Subalpine Fir in Norwegian Christmas Tree Plantations

Fig. 6. Two different isolates of Phytophthora megasperma from subalpine fir (Abies lasiocarpa) on V8 agar. The culture to the left has fluffy appearing mycelium and does not produce oogonia on agar. The culture to the right readily produces oogonia on agar and has very little aerial mycelium. Photo by V. Talgø.



Image from Plant Health Progress article:
Phytophthora Root Rot and Stem Canker Found on Nordmann and Subalpine Fir in Norwegian Christmas Tree Plantations