45 ; 
pure cultures of Phytophthora omnivora , De Bary, and with them to 
reproduce the pod disease by inoculation ; and finally, he refers to the 
work of Mrs. Van Hall in Surinam (1909) on the canker disease which 
was said to be caused by Spicaria colorans , n. sp. Having thus des- 
cribed the work of previous investigators on pod disease and canker 
of cacao, the author is careful to point out that whereas pod disease 
has been shown by inoculation experiments with pure cultures to be 
caused by Phytophthora omnivora, the canker has never been repro- 
duced by infection with spores derived from pure cultures. 
A description of the life-history of Phytophthora omnivora , is 
given, being based on the results of infection experiments. The fun- 
gus is shown to be capable of penetrating the unbroken surface of a 
pod either through the epidermis or through a stoma. When the 
tissues of the pod have become invaded by the fungus the mycelium is 
said to pass backwards to the cushion and to produce a cankered 
appearance of the cushions and of the surrounding area of the bark. 
Other infection experiments showed that the fungus could spread 
from the stem to the pods. 
A careful description is given of the inoculation experiments 
carried out with the following species : — Phytophthora omnivora , 
Diplodia cacaoicola ■ Nectria Theobromac, Neciria Bainii, Caloncctria 
jlavida, Spicaria colorans, and two species of Sphaeroslilbe . Positive 
results were obtained only with Phytophthora omnivora and Diplodia 
cacaoicola, and only in the case of the former was the cankered ap- 
pearance oi the stem produced. The author, therefore, concludes that 
the canker is caused by Phytophthora omnivora, and that the other 
species of fungi mentioned above, with the exception of Diplodia 
cacaoicola , are incapable of Effecting the healthy tissues of the plant. 
The infection experiments were numerous and in each case a pure 
culture of the fungus was employed. 
The remedial measures which are recommended for treatment of 
the canker and pod disease are : — 
(1) . Spraying the pods with a fungicide, in which experiments 
are said to be in progress for the purpose of determining 
the best fungicide and the most suitable time of appli- 
cation. 
(2) . Cutting out the cankered area on the stem. 
(3) . Avoiding needless wounding of trees and unnecessary 
shading. 
(4) . Better drainage. 
Phytophthora omnivora occurs as parasite wherever the cacao 
plant is cultivated ; but it has hitherto been supposed to be confined 
to the pods, causing a disease known in the West Indies as “ black 
pod-rot.” The author’s conclusion that the canker and pod-rot are 
caused by the same fungus is, therefore, contradictory to the results 
obtained by previous investigators. His work is, however, accurately 
