Collar Rot on Italian Alder Trees in California Caused by <i>Phytophthora siskiyouensis</i>

Fig. 2. Bole lesions in the tissues under the bark of a bleeding canker: (C) discoloration in the secondary phloem tissue.



Image from Plant Health Progress article:
Collar Rot on Italian Alder Trees in California Caused by Phytophthora siskiyouensis