MOSAIC OF SUGAR CANE AND OTHER GRASSES. 
11 
of roots and shoots at the nodes of standing cane. Figure 2 shows 
such a condition in Yellow Caledonia cane. The photograph repro- 
duced here was taken at Arecibo, Porto Rico, in 1919, and the 
probabilities are that the plant had been infected for at least five 
years. These iden- 
tical cuttings and 
similar ones were 
brought to Washing- 
ton and planted in 
a quarantine green- 
house. Most of them 
grew, but at the pres- 
ent time, five months 
after planting, they 
are scarcely 1 foot 
tall. The opaque 
white streaking 
covers practically all 
of the leaf area. This 
is the most excessive 
injury ever observed 
by the writer. Most 
varieties of cane do 
not go to pieces like 
this, but rather the 
injury to stalks con- 
sists merely of re- 
tarded development. 
Among the well- 
known varieties, 
however, all grada- 
tions in the extent of 
injury between these 
two extremes are to 
be found. 
When a large pro- 
portion of the plants 
in a field are infested, 
the aspect in general 
resembles the effect 
of a severe drought. 
The foliage of the entire field is yellowish, and the plants are more or less 
noticeably stunted. Where a row of some immune variety is planted 
in or near a badly infested field, the contrast in color is exceedingly 
conspicuous and the dwarfed habit of infected plants is more notice- 
Fig. 2.— Canker stag 
i in Yellow Caledonia sugar cane; healthy cane of 
the same variety in center. 
