Apr. 31,1933 
Cultivated and Wild Hosts of Cane Mosaic 
261 
the virus would be more likely to persist in seeds, if it survives at all, 
than in any other state. The possibility of its being carried over in the 
bodies of insect vectors is rather remote, since there is no evidence that 
such insects function as intermediate hosts, but rather as mechanical 
carriers, and as such they would not furnish the special conditions neces 
sary for long-continued survival of the virus. This view is supported by 
our results with artificial inoculations, which proved that development 
of the virus within the body of an insect is not necessary. We have 
fairly conclusive proof that the virus does not survive in plant trash or 
soil, even in tropical countries. Our evidence that the virus is not car¬ 
ried over in seeds (2) has been strengthened by the results of subsequent 
experiments with com, sorghum, and wild-grass seeds from mosaic 
parents, all of which gave rise to healthy plants. The results are shown 
in Table IX. 
Tabi^B IX .—Experiments to determine the transmission of disease by means of seeds 
from mosaic corn^ sorghum^ and wild grasses 
Number 
Results. 
Species. 
Date planted. 
germi¬ 
nated. 
Date examined. 
Condition of seed¬ 
lings. 
Zea mays var. White Creole. 
Nov. 30,1920 
44 
Jan. 25,1921 
All healthy. 
Zea mays var. U. S. Selec¬ 
.do. 
81 
.do. 
Do. 
tion No. 182. 
Zea mays var. White Creole. 
Dec. 15,1920 
100 
Feb. 15,1921 
Do. 
Zea mays var. U. S. Selec¬ 
.do. 
90 
.do. 
Do. 
tion No. 182. 
Holcus sorghum var. Honey. 
Sept. 15,1919 
181 
Nov. 30,1919 
Do. 
Do... 
Nov. 30,1920 
94 
Jan. 26,1921 
Do. 
Holcus sorghum var. Goose¬ 
neck. 
75 
.do. 
Do. 
Paspalum boscianum . 
Jan. 20,1921 
47 
Mar. 12,1921 
Do. 
Brachiaria platyphylla . 
.do. 
52 
42 
.do. 
Do. 
Syntfierisma so-nguinalis . 
.do. 
.do. 
Do. 
Observations by Vander Stok (74), Kobus (ii), and Wilbrink and Tede- 
boer (17) in Java indicate that sugar-cane seedlings from mosaic parents 
are healthy at the start and remain so unless infected from outside 
sources in the usual way. All available evidence, therefore, points to 
the conclusion that in this disease, as in tobacco mosaic, the virus is not 
transmitted from generation to generation by means of seeds. 
SUMMARY 
(1) Thirteen species of grasses have been proved by inoculation experi¬ 
ments to be susceptible to the disease known as sugar-cane mosaic or, 
more properly, grass mosaic. 
(2) Certain varieties of sugar cane belonging to the slender North India 
type, formerly regarded as immune, have proved susceptible to mosaic. 
(3) Data on the yield of 17 varieties of southern field corn show a de¬ 
crease in weight of 0.4 to 50.6 per cent, due to mosaic. 
(4) Field observations indicate that natural infection of sorghum, 
pearl millet, crab-grass, bull-grass, Chaetochloa magna, and Brachiaria 
platyphylla is widespread near affected cane in the sugar-cane belt. 
(5) All species tested for seed transmission of mosaic gave negative 
results. 
