Apr. ait Z933 
Cultivated and Wild Hosts of Cane Mosaic 
251 
It wfll be noticed that in the experiments the virus was treated in 
various ways. In at least one experiment virus which had been passed 
through a B^kefeld filter * caused infection in 75 per cent of the plants 
inoculated. Other similar experiments have failed to give such convinc¬ 
ing results, but owing to the fact that ccmtrol plants inoculated with 
untreated virus also show a low percentage of infection, indicating a less 
potent virus, the writers are inclined to attach considerable importance 
to the successful experiment and believe that the virus will pass through 
certain diatomaceous earth filters. 
In some experiments the virus was shaken in bottles with various 
bacteriacidal chemicals one hour before being injected into the plants. 
With one exception none of the virus treated in this way caused infection. 
One plant in a series of four inoculated with virus treated with weak 
phenol solution became mosaic in 14 days. The same lot of virus diluted 
with distilled water in various proportions gave negative results. Virus 
capable of causing infection when used immediately after being expressed 
from diseased stalks was found in one experiment to be wiAout effect 
when injected 24 hours later. The virus of grass mosaic is less stable or 
more sensitive to the influence of its environment than that of many 
other similar diseases, notably the tobacco mosaic. In these experiments 
it has been found very refractory and difficult of physical manipulation 
or chemical treatment without loss of virulence. 
The results of the experiments on insect transmission of the disease 
are g^ven in Table II. ‘‘Virulent** insects were obtained from mosaic 
sugar cane or from mosaic sorghum artificially inoculated with virus from 
sugar cane. “ Nonvirulent** insects were from healthy cane or sorghum. 
These experiments were performed in insect-proof compartments in a 
mosaic-infested greenhouse. 
TablQ II .—Composite record of the tests of the insect transmission of the grass mosaic 
Num- 
Results. 
Species* 
btf of 
I^ants. 
Date exposed. 
Character. 
Insect. 
Date 
examined. 
Condition. 
Saccharum oJHcma- 
J 
Peb. 4, Z920 
Virulent.... 
Aphis maidis ,. 
Feb. 281X920 
a mosaic. 
rum var. I^ouisi- 
ana Purple. 
Do. 
3 
.do. 
Nonvirulent 
.do. 
Mar. x4,z92o 
All healthy. 
Do. 
Do.__ 
6 
.do.... 
Virulent.... 
Draecidaceph- 
ala molipes, 
.do... 
Do .. 
6 
.do. 
Nonvirulent 
.do. 
Do. 
Zea mays var. U. S. 
6 
Mar. X2,z92o 
Virulent .... 
Aphis maidis .. 
Apr. 6, X920 
4 mosaic. 
Selection No. 182. 
Do. 
6 
.do. 
Nonvirulent 
.do. 
May 1,1920 
May 28,1920 
.do.. 
All healthy. 
ts mosaic. 
All healthy. 
Do. 
Do. 
ao 
Mar. 30,1920 
. ^_do..___ 
Virulent._ 
.do.. 
Do...,. 
20 
N onvirul^t 
__do... 
Triticum ' sativum 
50 
May 20,1920 
Virulent.... 
Aug. I, X920 
var. Power Fife. 
Do.. -. 
so 
SO 
.do. 
Nonvirulent 
.do,..,. 
Do. 
Hordeum vtUgare 
var. Marionet. 
.do.. 
Virulent.... 
.... .do. 
Do. 
Do.... 
SO 
so 
.do. 
N onvirulent 
. - -..do. 
.do. 
Do. 
SecaU cereale var. 
Von Runker 
No. a; 
.do. 
Virulent-... 
.do. 
.do. 
Do. 
Do.. 
SO 
SO 
SO 
-do. 
Nonvirulent 
.do. 
Do. 
Avena stUiva var. 
.do. 
Virulent,... 
.do. 
.do.... 
Dp. 
Swedish Select. 
Do. 
.do. 
Nonvirulent 
.....do. 
Do. 
* This was a rather coarse filter. When immersed in water it withstood a pressure of only 3 pounds 
before passing bubbles. . 
