CEREAL INVESTIGATIONS. 
July i, 1925 Overwintering and Dissemination of Cucurbit Mosaic 49 
SYMPTOMS OF CUCURBIT MOSAIC ON THE PEPPER 
When inoculated with cucurbit mosaic, the symptoms of the 
disease develop in the pepper in a manner which is very similar to 
that noted in the cucumber. The younger leaves of the infected 
plant curl downward along the midrib and the basal portion of the 
leaf is frequently a lighter green than that at the tip. Within a 
short time, however, such leaves develop the mottled appearance 
characteristic of the disease. The contrast in color, however, is 
seldom as pronounced as in the cucurbits and the mottling of the 
leaves is not general as in the cucumber, as only the very young 
leaves and those produced after infection are affected in this way. 
When pepper plants have been mosaic diseased for some time, the 
leaves are considerably smaller than those of healthy plants of the 
same age. The stem internodes are shortened considerably and the 
length of the petioles is somewhat reduced. Mosaic plants have a 
more compact habit of growth than normal plants, and the leaves 
are often abnormally narrow and drawn out in filiform fashion at 
the tip (pi. 6, A). This character of growth often produces an almost 
rosettelike character in plants which are infected when young. The 
foliage of mosaic peppers becomes a yellowish green, and the leaves 
appear to be firmer m texture than those of healthy plants. The 
mottling of the leaves is also less pronounced in plants which have 
been infected for some time and may be so slight as to be almost indis¬ 
tinguishable except upon close examination. In a few cases the 
fruits of mosaic pepper plants have shown symptoms which are com¬ 
parable to those found on the fruits of the cucumber (pi. 3, B, C, D). 
The greater part of such fruits retain their normal green color, but 
the surface is broken with dark-green areas which are raised above 
the surface in warty swellings similar to those found on cucumbers 
affected with mosaic. 
INTERTRANSMISSION OF CUGUMBER AND TOBACCO MOSAIC 
The discovery of the susceptibility of the pepper to cucurbit 
mosaic has been of particular interest, since both Allard ( 1) and 
Schwarze (18) have shown that the pepper is also susceptible to the 
mosaic disease of tobacco. A comparative study was made, there¬ 
fore, between pepper plants inoculated with tobacco mosaic and those 
inoculated from mosaic cucumber plants. These experiments indi¬ 
cated that pepper plants inoculated from mosaic plants of either 
of these hosts behaved in essentially the same manner. The period 
of incubation was the same and the symptoms appeared to be of the 
same type in both cases. The plants were dwarfed, and the leaf 
symptoms were the same as those described above (pi. 6, A, B, C). 
The pepper is also susceptible to tomato mosaic and it was found that 
peppers inoculated from mosaic tomato plants also showed symptoms 
apparently the same as those found on peppers inoculated from mosaic 
cucumber plants. This would be expected,' in view of the results 
with tobacco, the infective agency of tobacco and tomato mosaic 
being apparently the same. 
Since the pepper was susceptible to both cucumber and tobacco 
mosaic, the possibility was suggested that the mosaic of one of these 
hosts might be transmitted to plants of the other host through the 
