Aug. zx, 1923 
Phytophthora Faberi on Coconut and Cacao 
2 71 
strains. The green fruits were not so rapidly attacked. In two days 
there was only a slight rot produced on the green fruits, but a severe rot 
on the ripe ones. Later a dense growth of mycelium developed on the 
surface, appearing first on the ripe fruits. At the end of nine days, all 
fruits, both green and ripe, were severely rotted and covered with a 
mass of white mycelium which arose through the epidermis from within 
the fruit (PI. 6, A and B). The green fruits were browned and darkened 
within, while the ripe fruits were only softened. Microscopic examina¬ 
tion showed the presence of an intercellular mycelium throughout the 
entire fruits. A pure culture of the fungus was present on the surface 
with many chlamydospores and conidia. 
Ben Davis apples were easily attacked and rotted by both strains of 
the fungus. Within five days after the inoculation through the epider¬ 
mis, a rot spreading 4 cm. beneath the skin and extending to the core 
was produced (PI. 6, D and E). The rotted area was brown and rather 
mealy. Microscopic examination showed an abundance of character¬ 
istic intercellular mycelium throughout the rotted area. 
Both strains of the fungus infected cacao pods, developing the charac¬ 
teristic blackrot. The strain isolated from cacao appeared to be more 
virulent. 
The rot of potatoes was produced rather slowly by both strains. Irish 
Cobbler and Rural New Yorker potatoes were used for the inoculations. 
After 6 days a slight rot developed and within 30 days the rot extended 
to the center of the tubers. The infected potatoes, in certain cases, 
showed the symptoms as recorded by Pethybridge (5) on the rotting of 
potato tubers by a new species of Phytophthora. No definite line of 
demarcation between the healthy and diseased portions was noted im¬ 
mediately after cutting the tubers. A blackish line at the extremity of 
the infection and following around with the vascular system just beneath 
the surface then developed. Soon after cutting the tubers, the affected 
portion appeared somewhat watery, and in 15 to 30 minutes a distinct 
pinkish to red coloration was formed in the rotted region. Later, on 
longer exposure to the air, the invaded parts turned a purplish black. 
Not in all cases of infection did the pinkish or reddish coloration develop. 
Microscopic examination of the infected areas showed the presence of an 
intercellular, nonseptate, granular mycelium. 
Garden bush pea plants were readily attacked and severely blighted 
by both strains of the fungus. In six days after inoculation a severe blight 
was produced. A whitish mass of mycelium formed over the blighted 
parts. The mycelium was present in the intercellular spaces of the 
affected tissue. 
The consistent similarity in the attack of various hosts by both strains 
of the fungus shows that in this respect there is a constant likeness. 
In no case, except probably with the cacao fruit, was there any difference 
noted in the virulence of the two. Both are omnivorous, capable of 
attacking a large number of different hosts. 
PHYSIOI/OGICAI, CHARACTERISTICS 
GROWTH ON VARIOUS MEDIA 
The two strains grew well on a variety of media, the character of the 
growth being similar for each. Since the two grew alike in all partic¬ 
ulars, a separate description of each will not be given. The following 
discussion applies equally well to either. The descriptions were made 
