14 BULLETIN" 829, U. S. DEPARTMENT OF AGRICULTURE. 
Iii Cuba all varieties that are exposed seem to become infected, 
but since the disease has not become rampant nor spread over any 
considerable area no opportunity to observe the reaction of all the 
varieties grown there is to be had. Practically all of the seedlings 
originated in the Harvard Experiment Station near Cienfuegos were 
affected, as well as the imported Java 228, L 511, and the native 
Crystalina at Santiago de las Vegas. 
Practically all varieties are attacked in the Hawaiian Islands, and 
extensive damage is done. 
The common varieties in Louisiana have proved susceptible to 
mosaic disease. Louisiana Purple, Louisiana Striped, I) 74, D 95, 
L 511, L 218, L 219, L 226, L 231, L 253, and hundreds of seedlings 
being tested at the Louisiana Sugar Experiment Station all fall prey 
to the ravages of this disease. 
IMMUNE VARIETIES. 
Fortunately a few varieties of sugar cane have been discovered 
which appear to be entirely immune. Most of them are of the 
slender North India type, generally known as Japanese canes. The 
Kavangire, a variety which, because of its proline stooling, yields a 
very large tonnage and is much esteemed in Argentina for making 
sugar has never been observed to be diseased, although it has been 
exposed to infection for four years in the wrorst infested regions of 
Porto Rico. 1 It is a rather long season cane, however, and for this 
reason is probably not suited to Louisiana conditions. Another Jap- 
anese cane, Cayana 10, which is becoming prominent in the sirup 
sections of Georgia and Florida, is also immune. This variety has 
already met with considerable favor on the part of cane growers in 
Georgia. All the other Japanese varieties observed, including many 
imported by the Office of Foreign Seed and Plant Introduction of 
the Bureau of Plant Industry, have been found to be uniformly free 
from this disease. 
Among the broad-leaved thicker stalked varieties several kinds 
have been found that appear to be immune, but our evidence of their 
immunity is not so complete as is the case with the Japanese varieties. 
Louisiana seedlings 1646, 1606, 1674, and 1797, growing in the 
variety test plats at Audubon Park, New Orleans, this year appeared 
to be immune. No individuals of these varieties were diseased, 
although they were surrounded by other varieties, the individuals 
of which averaged 97 per cent diseased. 
1 Tuwnsend, C. 0. An immune variety of cane. (Abstract of an article by F. S. Earle.) In Science, 
n. s., v. 49, no. 1272, p. 470-472. 1919. 
