PLATE i6 



Confusing forms of blackleg potato tuber-rot in the West (all specimens collected 

 in Idaho). 



A, B. — ^Netted Gem variety one month after digging. Tuber B as it appeared on 

 the first day after digging is shown in Plate 15, B. 



C. — Long Idaho Rural, showing secondary growth of Rhizoctonia on the outside 

 and active bacterial decay in the inside. 



D. — Idaho Rural with deep side infection of blackleg decay which became dry 

 and spongy on exposure to the sun. 



E. — Shallow surface infection which became dry and black when exposed to the 

 sun after digging. 



