ON THE SCALE INSECT OF MULBERRY TREES. 



T2I 



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 brandies, 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 : — 



1. Water i litre 



2. Fish oil 32 gr. 



3. Bicarbonate of Soda 32 gr. 



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 Chalcidae and the other a 

 coleoptera belonging to Coccinellidse. Both of these decrease the 

 number of the pest every year to a certain extent. 



Tokyo, January 1894. 



