POTATO DISEASES IX HAWAII. O 
The mere fact that the seed purchased is from the coast is not 
sufficient indication of freedom from disease. Imported seed and 
table stock used for seed purposes in the Territory are constantly 
found infected with several serious diseases, among which are 
Fusarium wilt, Rhizoctonia, black scurf, corky scab, etc. (See figs. 
1 and 2.) Unless the seed is carefully inspected there is always the 
possibility of introducing diseases not hitherto prevalent in the 
islands. If mainland seed is used, the certified sort should be in- 
Fig. 1. — Potato diseases not controllable by treatment. Sort out and reject all tubers 
which look like these : A, Common scab, a severe case ; B, internal browning ; C, late 
blight dry rot ; D, Fusarium dry rot : E, blackleg tuber rot ; F, internal browning ; G, a 
wilt-infected tuber with discolored ring at the stem end. (From U. S. Dept. Agr., Bur. 
Plant Indus., C, T.. and F. C. D. Circ. 3.) 
sisted upon. Before planting it should be examined, sorted, if neces- 
sary, and disinfected with one of the fungicidal solutions (p. 9). 
The Fusarium wilt is a most serious disease almost constantly 
carried by imported seed (PI. I) and very prevalent in California. 
Probably the best source of seed for Hawaii is the Willamette 
Valley. Oreg., where the Fusarium wilt is of infrequent occurrence. 
The seed certification boards of some States allow a small percentage 
of blackleg in stands passed as certified stock. It is necessary, there- 
fore, to inspect carefully all imported seed for blackleg-infected 
tubers (see fig. 7, p. 38) and to sort these out and destroy them. 
The seed plat. — In the chief potato sections a portion of the farm 
should be set aside for growing seed potatoes for subsequent plant- 
