14 BULLETIN 879, U. S. DEPARTMENT OE AGRICULTURE. 
fruit first becomes mottled with yellowish green, this mottled char- 
acter gradually spreading over the entire fruit. As this progresses 
the body of the fruit ordinarily becomes a light yellowish green, inter- 
mingled with spots of a much darker green color. These dark por- 
tions are usually raised above the surrounding surface in such a way 
that they form wartlike projections and often produce more or less «* 
distortion of the fruit. 
The number and size of these protuberances vary greatly, and we 
find many types of affected fruits (PI. VIII). In some cases, particu- 
larly in the greenhouse, the mottled character is very marked, the 
fruit being covered with mingled blotches of light and dark green, but 
with little or no wart production or distortion of shape. Such fruits 
are common in the field, as also those in which the stem end is the 
only part to show a well-defined mottling. 
More commonly, however, the dark-green portions of the surface 
are distinctly raised, the projections varying from 1 millimeter up to 
2 centimeters in diameter and from 1 to 6 millimeters in height. The 
general appearance of all such fruits is the same, but the minor char- 
acters are subject to great variation. In some cases the warts are 
small, sharply outlined, isolated, and scattered over the surface in 
varying numbers (PI. VIII, A to C). On other fruits they are larger, 
coalesce to some extent, and form irregular raised patches, which are 
sometimes slightly elevated and do not greatly affect the shape of the 
fruit, while in still other specimens they are so large as to produce an 
extremely rough and irregular form (PL VIII, D, E). In some cases 
there may be one or two large warts, often at the stem end, the 
remainder of the fruit being yellowish white or mottled with yellowish 
green, but nearly as smooth as normal. 
In general, however, the fruits are decidedly mottled in appearance/ 
and show swellings of all sizes, some isolated and others merging 
into one another in such a way as to produce a very irregular form, 
the symptoms often being well defined on fruits which are but an 
inch in length. The fruits of this type have given rise to the names 
"wart disease" and " nubbin," which have been applied to the disease 
by growers in some parts of the country. 
In the later stages of the disease the vines occasionally produce 
fruits which are smooth, pale whitish green in color, and rather more 
blunt at the ends than normal fruits of the same age. In most cases 
these fruits are mottled with fine spots of yellowish green, and a few 
dark-green projections appear here and there on the surface. (PI. J, 
VIII.) These are usually small, but occasionally fruits are found 
which have a single large dark-green swelling near the stem end, 
producing a most unusual appearance. 
These white fruits are responsible for the older common name of 
the disease, "white pickle," which was the term applied to the trouble 
