Florida Agricultural Experiment Station


tious substance is contained in diseased plants and is known as
"virus." Extensive research work has been conducted in various
places in an effort to isolate from the plant the principle causing
mosaic. This work has not yet been successful.
 In the United States the disease is widespread and may occur
wherever cucumbers are grown. Although it is generally distrib-
uted over the cucumber area of the United States, mosaic has
been severe in relatively few states and these instances have been
in the north. The disease appears to be becoming relatively more
important in Florida. Several years ago its occurrence was rela-
tively rare but during the past year or two it has become more
common and certain fields during the past season showed losses.
A specific six-acre field showed 18 percent infected plants by
actual count and about 20 percent of the picked fruits were dis-
carded as culls because of the mottling and wartiness of their
surfaces. Cull piles of mosaic fruit (Fig. 18) are quite unique and
seldom seen. There appears to be a higher percentage of mottled
fruit in Florida fields than in northern fields when the numbers
of infected plants are about equal.


 Fig. 18. Cucumber cull pile made up of mottled, warty fruit resulting
from the mosaic disease.