Nov. xo, 1923 
Two Diseases of Udo 
277 
inoculated plants showed the early symptoms of the disease, and after a 
time more leaves became yellow. None of the controls or other plants 
growing near showed any dying or yellowing of the foliage. 
This disease works slowly; the tops die gradually, and by the end of 
the season some of the plants may be dead, while others are living, 
though stunted and low in vigor. The living plants may make some 
growth the following year, and the disease may require two years or even 
longer to kill a plant completely. 
The browning of the vascular system is apparent in these diseased 
plants—a characteristic of vascular diseases of other plants. The myce¬ 
lium was found extending down to the tips of the roots, as well as up into 
the stem. It was isolated from the petiole of a leaf about 3 feet from the 
ground. 
In order to learn whether or not this strain of Verticillium alboatrum 
causing wilt of udo would cause wilt of eggplant, the following experi¬ 
ment was performed. Fifteen eggplants were inoculated with the Verti¬ 
cillium from udo by the method described above, and 15 others were 
inoculated with a strain of the same fungus isolated from a wilted egg¬ 
plant. Thirty plants of the same lot were held as controls. In 15 days 
unmistakable symptoms of the disease were present in some of each set of 
inoculated plants. Three days later an examination showed that 10 of 
the plants inoculated with the fungus from eggplant were dying, one 
being already practically dead, and 6 plants inoculated with the fungus 
from udo were diseased. The remaining plants showed no signs of the 
disease, nor did any of the controls. This experiment was repeated 
later, 10 plants being inoculated with each fungus. All of the plants 
inoculated with the fungus from eggplant and 7 inoculated with that 
from udo became infected. Evidently these two fungi were identical, 
not only morphologically, but parasitically. It is of interest to know that 
these fungi were isolated from naturally infected eggplant and udo 
growing in the same garden. The udo had been planted on soil which 
had previously grown wilted eggplants. Undoubtedly the strain of 
Verticillium which causes wilt of eggplant also causes the same disease 
of udo. Carpenter (3) has shown that Verticillium alboatrum isolated 
from okra, snapdragon, eggplant, and Irish potato will infect okra, and 
that the same fungus from eggplant, okra, and snapdragon will infect 
eggplant. It would seem, then, that Verticillium alboatrum f regardless of 
its source, is capable of attacking a number of plants in which it produces 
a characteristic wilt disease. 
CONTROL 
Only sanitary measures can be suggested for the control of this disease. 
These may be briefly stated. Do not sow udo on land on which any 
plants affected with Verticillium wilt have been grown. It is not known 
whether or not this disease can be spread by means of infected seed, 
but it seems advisable to avoid such a possibility. If the disease 
appears the affected plants should be removed, great care being exer¬ 
cised not to spread the fungus about the field. Cuttings for propagation 
should never be made from diseased plants. When so many of the plants 
become diseased that the planting becomes unprofitable it should be 
abandoned and the plants destroyed. The new planting should be made 
as far away fom the old one as possible. 
There are indications that the wilt is less destructive on a heavy soil 
than on a lighter, sandy loam. 
