XIV, 6 Lee and Yates: Pink Disease of Citrus 669 - 
is, at the beginning of the wet season, in the middle of the wet 
season, and toward its close. Should heavy rains and high hu- 
midity continue into August, another application in August 
would be advisable. 
It should be emphasized that moisture conditions vary greatly 
in different parts of the Philippines and that the time for spray- 
ing in different islands would also vary with the periods and 
degree of rainfall in the various localities. 
It seems probable that similar control methods would prove 
of value against pink disease of tea, coffee, cacao, and other 
crop plants, although we have no experimental data on which 
to make a definite statement. 
DISCUSSION OF THE SERIOUSNESS OF PINK DISEASE AND ITS 
OCCURRENCE IN THE PHILIPPINES 
Pink disease when uncontrolled causes serious injuries and 
often results in the death of entire trees and consequent econom- 
ic losses. Plates V, VI, and VII show some of the effects of 
the disease. At present it is apparently not widely distributed 
in the Philippine Islands; but, should control measures not be 
adopted, conditions in regard to this disease may be expected 
to develop similar to those existing in the Federated Malay 
States, where the disease had gained a foothold before its serious- 
ness was appreciated. Pest gangs are now maintained upon 
many rubber estates there for the purpose of disinfecting Corti- 
cium wounds and treating other diseases. It is to be hoped that 
Filipino planters will profit by experience in other countries, 
especially as the activities of the disease on Citrus trees at Lamao 
indicate what may take place if no control methods are attempted. 
In an area of not more than 12 hectares (30 acres) at least three 
hundred cases of Corticiwm have been observed. It should be re- 
membered also that pink disease is a killing disease rather than 
one that merely takes its percentage from the financial returns 
by lowering the efficiency of the tree. 
Although control by spraying and pruning is simple and 
comparatively inexpensive on Citrus, because of its localized 
occurrence at present, it seems possible to go further and en- 
tirely eradicate this disease from the Philippine Islands. Such 
eradication being effected, enforcement of adequate quarantine 
regulations should prevent the reintroduction of Corticium sal- 
monicolor B. & Br., and the continual fight against the disease 
and the consequent expenditure of money would not need to be 
