PLATE 13 
Phoma tuberosa on Solatium tuberosum: 
Fig. A, B.—Stages of the rot caused by Phoma tuberosa on the Irish potato. The 
size and appearance of the lesion as shown in figure B is the most common. The 
abundance and size of the pycnidia vary. 
Fig. C, D, E.—Results of artificial inoculation with pure cultures of Phoma tuberosa. 
Figure D shows an injured uninoculated tuber. Figure E shows the buttonhole lesion 
produced 10 days after inoculation. Figure C shows a tuber from another series three 
weeks after inoculation. Note the similarity of this lesion and that shown in Plate 
12, figure A. 
