20,2  Leeand Shino: Citrus-canker Control Experiments 145 
copper-precipitate mixtures. This increase of red spider was 
noticeably slight or absent from the lime-sulphur, formalin, and 
unsprayed plats. 
The injury resulting from the red spider, melanose, and sooty- 
mold blemishes very largely depreciated the commercial value 
of the favorable results in the reduction of citrus-canker infec- 
tions. However, the increase in sooty mold and red spider may 
be readily avoided by the addition of oil emulsions to the copper- 
precipitate sprays. In fact, it was through a misunderstanding 
between the writers that an insecticide was not added to the 
spray mixtures in August. It is suggested also that it might be 
desirable to spray with one of the copper sprays in June and 
July, and change to lime sulphur in August. A very noticeable 
result from the experiments, and one which elicited consider- 
able favorable comment from the growers, was the luxuriant 
green of the foliage and the clear, flawless color of the fruits 
of the lime-sulphur plats. It would seem desirable, therefore, 
for future investigators to attempt a schedule of copper-pre- 
cipitate sprays during the early part of the rainy period, chang- 
ing to lime sulphur as the rains become less. Another suggestion 
for future experiments is that lime sulphur be employed at more 
frequent intervals. The control of sooty mold and red spider is 
so simple that these deleterious results scarcely need be consid- 
ered as affecting the experimental value of the results showing 
canker reduction. 
Following the use of the sprays employed in these experiments 
there was no noticeable insipidity or reduction of acidity of 
the fruits, such as has been described by Gray and Ryan(1) 
following lead arsenate sprays. 
EFFECTS OF CITRUS CANKER UPON THE WASHINGTON NAVEL 
ORANGE ; 
In the literature on citrus canker in America, very little has 
been stated as to the injuries resulting from the disease. This 
has been primarily because of the eradication work which has 
made continued observations upon commercial citrus plantings 
impossible. For a satisfactory understanding of the present 
control data it seems advisable to state briefly the effects of 
citrus canker in Nagasaki Prefecture, Japan. 
Citrus canker affects the foliage and fruits of the Washington 
navel orange; twigs are rarely attacked and the mature wood 
is not commonly affected, as is the case with the very suscep- 
tible varieties of West Indian limes and American grape fruits. 
