ON THE SCALE INSECT OF MULBERRY TREES. 
121 
although the scales of the female insects remain throughout the 
year, they can not easily be seen on account of their dull brown¬ 
ish grey color, which is very similar to that of the bark on which 
they remain tightly attached. 
When the scale insects are found parasitic in swarms or lots 
on stems or branches, the growth of the latter is more or less 
interrupted by the loss of sap, as they may be weakened to a 
certain extent, and particularly much more injury is done to the 
younger stems or shoots than to the older ones, as the former 
most frequently perish. Great as is the damage done by the 
scale insects to the mulberry trees, few owners of trees take any 
particular pains to destroy these formidable pests. The only 
method commonly practised is to scrape off the scales from the 
bark with small thin pieces of wood or bamboo, or sometimes 
with the shells of ear-shells or mussels. 
The preventive methods which I consider most efficacious 
and most practicable for destroying this pest, is the spraying of 
lime water, petroleum, or a mixture of water, fish-oil, and 
bicarbonate of soda in the following proportion :— 
I. 
Water 
i 
litre 
2. 
Fish oil 
32 
gr. 
3 - 
Bicarbonate of Soda 
t x 
32 
g r - 
These preventive mixtures are more efficacious when applied 
in dry weather during the months of June to October; for 
during these months, the active young larvae mostly distribute 
themselves by crawling about, or remain fixed on the bark 
without protection. 
The method of the propagation of the insects are not as 
yet clearly known, but most probably it may be done during the 
first larval stage by the wind. 
There is two natural enemies of the scale insect, one being 
a hymenopterous insect belonging to Chalcidæ and the other a 
coleoptera belongingto Coccinellidæ. Both of these decrease the 
number of the pest every year to a certain extent. 
Tokyo, January 1894. 
