668 Philippine Journal of Science 1919 
the affected places with tar. Although it does not seem rea- 
sonable to assume that such applications penetrate and kill the 
mycelium within the tissues, the report states that control is 
obtained in most cases. These results are in agreement with 
the observations made in the Philippines on the superficial ap- 
plication of fungicides; there, strangely enough, such applica- 
tions have resulted in apparently complete control. 
Although spraying is usually not practicable against pink dis- 
ease on rubber, because of the size of the trees, it would seem to 
be the simplest method for the control of this disease on Citrus, 
since the application of fungicides may be combined with control 
methods against citrus canker, citrus scab, and, when lime sul- 
phur is used, against scale insects. It seems probable that spray 
applications in connection with pruning would also prove an 
effective and simple control of the disease upon cacao, coffee, 
tea, and similar plants. 
RECOMMENDATIONS 
It is apparent that a control approaching almost complete 
eradication has been attained at Lamao. It seems probable that 
the fundamental procedure is the careful removal of affected 
limbs together with precautionary disinfection methods. How- 
ever, it is also apparent that much can be accomplished by 
spraying as a preventive measure. Although copper sprays, 
such as Bordeaux and Burgundy mixtures, have proved successful 
against pink disease, they have the disadvantage of killing the 
fungus parasites of scale insects, thus bringing about a great 
increase in the latter. The use of copper sprays, therefore, is 
not recommended in the treatment of pink disease on Citrus, 
because of the great increase of scale insects following their 
repeated application. For this reason lime sulphur is suggested, 
not only because it is apparently as efficacious as are the copper 
sprays against pink disease, but also because it has been found 
of value against scale insects. Lime sulphur 1 to 40 is suffi- 
ciently strong, although it has been found that lime sulphur 1 
to 35 will cause no injury to the foliage of citrus trees. A dis- 
cussion of the preparation of lime sulphur is given by Waite.* 
The time for spray applications varies with the season. For 
a normal season in central Luzon an application about May 15, 
another June 15, and another July 15, should be sufficient; that 
* Waite, M. B., Fungicides, and their use in preventing disease of plants, 
Bull. U. S. Dept. Agr. 243 (1916). 
