20, 2 Lee and Shino: Citrus-canker Control Experiments 137 
in the field notes, that in the plats sprayed with Bordeaux and 
Burgundy mixtures, there was little increase in canker resulting 
from the nyubei. Although there was a slight canker increase 
on the lime-sulphur plats following the nyubei, it was not exten- 
sive. Basing the spraying campaign upon the weather reports 
for fifteen years, collected in Nagasaki Ken, no spray applications 
were planned following the nyubei, in late July or early August, 
since typhoons usually did not occur until later. In following 
this plan the experiments suffered, as Tables 6 and 7 indicate. 
On August 2, 3, 4, and 5 a typhoon occurred, and a violent 
southwest wind swept the orchard, accompanied by rain. On 
August 14, 15, 16, and 17 another typhoon swept across southern 
Japan, with another rainstorm and violent southwest winds 
striking the orchard. Both of these typhoons occurred at a 
time when the trees were entirely unprotected by spray coatings. 
The experiments were therefore unfortunate in this one way, in 
that the mean seasonal conditions did not occur. 
EXPERIMENTAL RESULTS 
The effect of the various treatments upon the plats was 
measured by the number of fruits free of canker. Citrus canker 
except on the extremely susceptible hosts, the American grape- 
fruit and West Indian lime varieties, is primarily a fruit blemish. 
The limbs and twigs are not seriously attacked, and the foliage 
infection is no more serious than citrus scab. By determining 
the number of fruits affected, therefore, the commercial value 
of the treatments is very closely determined. Moreover, the 
data thus obtained for the control plats constitute probably the 
most-definite measurement of the commercial losses, due to 
citrus canker, so far obtained. 
The results from the various treatments are shown in Table 8. 
From Table 8 it is evident that (a) all of the spray mixtures 
except formalin have reduced citrus-canker infection; (b) the 
Bordeaux mixtures apparently caused greatest reduction in citrus 
canker; there are not sufficient data to form any conclusion as 
to which is the better of the two mixtures employed; (c) Bur- 
gundy mixtures, although producing substantial reductions in 
the amount of canker, in no case equaled the Bordeaux mixtures 
in this regard; (d) formalin was the least effective of the sprays 
employed and was entirely without value; (e) lime sulphur re- 
duced citrus-canker infection materially, but in no case to the 
extent that the copper sprays did; lime sulphur, however, had 
other advantages, as will be described later; (f) the very care- 
1843502 
