17 , 6 
Lee: Black Spot of Citrus Fruits 
637 
sequently isolations were also made from Chinese fruits found 
on the Manila markets, and a fungus was isolated which on 
comparison with cultures from Nagasaki proved to be identical. 
The fungus answered closely to McAlpine’s description of 
Phoma citricarpa. 
Inoculation experiments were taken up in Manila ; all necessary 
precautions were taken to maintain such inoculations under 
quarantine, although the presence of severely affected Chinese 
fruits in the distant provincial markets were an almost constant 
source of infection of Philippine-grown fruits had conditions 
been favorable for infection. The preliminary series of inocula- 
tions are here tabulated with the results obtained. The fruits 
were first disinfected with alcohol, and both control and fungus 
inoculations were made with needle punctures. All of the fruits 
were then held in a chamber maintained at laboratory temper- 
atures (from 29° to 32° C.) and with slightly increased at- 
mospheric moisture. 
Table 1 . — Inoculations on mature Washington navel oranges, with tap water 
as controls, and with pure culture of Phoma citricarpa. 
[Inoculated April 14, 1920; date of observation of results. May 9, 1920.] 
Fruit No. 
Punc- 
tures per 
fruit. 
Inoculum. 
Positive 
results. 
1. _ _ 
20 
Per cent. 
0 
2 
20 
0 
3 
20 
0 
4 
20 
Phoma citricarpa culture. 
30 
5 
20 
70 
6 
20 
95 
The lesions obtained by these inoculations with the fungus 
were usually dead black in the center, becoming a deep brown at 
the edges (Plate 2) . The fruits could not be held as long as was 
desirable because of the quick infection with rotting fungi in 
the warm Manila conditions; fruiting bodies were not found 
on the surface of the positive cases in the twenty-four days dur- 
ing which the fruits were held. Reisolation, however, on agar 
plates resulted in the recovery of the fungus in the five cases 
tried. 
Inoculations with the fungus and controls with tap water made 
at the same time on six similar Washington navel oranges, but 
