270 
Journal of Agricultural Research 
Vol. XXV, No. 6 
Livistona rotundifolia appeared to be the most susceptible. 
A medium to severe infection was produced in the seedlings Phoenix 
dactylifera and Ptychosperma mearthurii . 
Evidence previously given (7) has also proved conclusively that the 
Phytophthora isolated from cacao will produce a typical case of coconut 
budrot in injured and uninjured trees (PI. 3, B). The fungus isolated 
from cacao and used for the comparative tests was also highly parasitic 
on the pods and branches of cacao (PI. 2). 
In order to determine whether the two fungus strains would both, in 
a similar manner, attack a variety of hosts, various inoculation experi¬ 
ments were conducted. It is realized that these inoculation tests can 
not alone be used to distinguish between various species of Phytophthora, 
but taken into consideration with the physiological and morphological 
characters, it is an added step toward proving the similarity or dis¬ 
similarity of two of the strains. In every instance in the inoculation 
experiments, reisolations of the fungus from the diseased plants were 
successfully made. All controls remained healthy. The results of the 
various cross inoculations in which cases both strains of Phytophthora, 
one from coconut budrot and the other from blackrot of cacao, were 
used, are summarized as follows: 
Seedlings severely infected by both strains— 
Annona muricata (guanabanos, soursop). 
Cocos nucifera (coconut). 
Hevea brasiliensis (Hevea or Para rubber). 
Theobroma cacao (cacao). 
Seedlings slightly infected by both strains— 
Annona glabra (annonas). 
Mangifera indica (mango). 
Sandoricum Koetjape (santol). 
Fruitrot produced by both strains— 
Carica papaya (papaya). 
Lycopersicum esculentum (tomato). 
Malus mains (apple). 
Theobroma cacao (cacao). 
Tuber-rot produced by both strains— 
Solanum tuberosum (Irish potato). 
Vegetable blight produced by both strains— 
Pisum sativum (pea). 
The coconut and cacao seedlings were readily killed by inoculation 
with either strain of the fungus. A severe blight of the Hevea rubber 
seedlings was produced. Under certain conditions a stemrot of 6 cm. 
developed in three days. On the soursop a rot 5 to 6 cm. in extent was 
formed by the attack of both strains. 
The rotting of papaya fruit was brought about in the same manner 
by both. After the first day, the fungus mycelium was well developed 
on the surface and in the interior of the fruit. In the early stages 
a white, cottonlike growth was formed (PI. 1, B). The diseased part 
was slightly discolored, being a darker yellow, especially marked at 
the boundary of the circular advance of the fungus. Microscopic 
examination showed the presence of the mycelium within the diseased 
tissue and the production of numerous spores on the surface. A softrot 
was finally formed. 
Ripe and green tomato fruits were also rotted by both strains of the 
fungus. The appearance and rapidity of the rot was identical for both 
