22 BULLETIN 45, HAWAII EXPERIMENT STATION. 
Glenwood, and there is every indication that this variety may solve 
the blight problem for such districts. 
The spraying with Bordeaux mixture thus far carried on by the 
writer and his associates for the prevention of wet blight or late 
blight has resulted in an increase in the crop of from 50 to 200 per 
cent by weight. (See Pis. Ill and IV.) 
Resistant varieties. — For many years attention has been directed 
to the development of varieties resistant to the late blight in Europe 
and on the mainland of the United States, but thus far without 
striking success. Varieties showing resistance have been types not 
in demand on the American markets. 
A type of potato originated by Miss Yamata, of Honokaa, Hawaii, 
is reported to be much more successfully grown in that locality than 
any other sort. This type of resistant potato, of which there are 
two strains, has received the name Hamakua Hybrid from the dis- 
trict in which it first came to the attention of the station. One 
parent of both strains appears to have been the local variety known 
as the Portuguese Purple, originally brought to the islands by 
Portuguese immigrants. One form of the Hybrid is a white and 
purple mottled tuber, of the general shape of a Burbank, with rather 
deep sprouts and eyes. The other, possibly a cross between the 
Portuguese Purple and the Early Eose, has a pink spin and purple 
eyes and sprouts, and is a more desirable tuber for market. 
Practical results support the view that this Hybrid has a promis- 
ing degree of resistance to late blight in these islands, but experimental 
evidence is somewhat conflicting. At Glenwood two experiments by 
different workers have shown its practical value in that district. 
Four acres of the variety grown in this section yielded over 400 bags 
of 100 pounds each. At Castner a small patch of the Hybrid and the 
Portuguese Purple varieties planted October 20, 1917, was unaffected 
by late blight on February 1, 1918, when other potatoes planted at 
the same time within a few hundred feet were devastated by the 
disease. The grower stated that Burbank potatoes planted at the 
same time as the Hybrid and adjoining them were all dead in 60 
days. The Hybrid, therefore, grew through a period of more 
than three months of weather suitable for late blight. They showed 
some early blight spots but no trace of the late blight disease. 
In order to test the blight resistance of the Hamakua Hybrid, it 
was also grown in comparison with the Early Rose variety in a small 
plat at Castner substation (PI. V). Owing to the poor soil there, 
the yield of neither variety is normal, but the resistance of the Hama- 
kua Hybrid to late blight is striking. Both varieties grew well the 
first month, but at the end of 60 days the tops of the Early Rose had 
been destroyed by the late blight (PL V), the 96 hills yielding only 
TJ pounds of tubers the size of marbles. The Hamakua Hybrid re- 
