The Mussel Scale. 



IS 



The Mussel Scale or Oyster-Shell Back Louse. 



{Mytilasjtis pomorum, Bouche.) 



Numerous enquiries are constantly being made by fruit-growers 

 and gardeners concerning the Mussel Scale (Mi/tilasjns jJomorum). 

 There being no leaflets issued or other ready information for fruit- 

 growers, the following notes have been prepared with a view to 

 meeting this want. 



The Mussel Scale is found chiefly on apple, but also on pear, 

 currant, plum and wild Crataegus, such as the Hawthorn. I have 

 also found it abundantly on Blackthorn in Devonshii-e. This 



Fig 8. — mussel scale {Mytilaspis pomonim). 

 a, Upper ; b, lower siu'face of ? scale ; c, <f scale. (Greatly enlarged.) 



pest, the worst scale insect we have in Great Britain, is found in 

 North America, and also in Australia, New Zealand, and South 

 Africa, having been imported on nm:sery stock. In this latter way 

 it is also largely distributed in this country. The necessity of 

 fumigating young stock before planting is thus rendered essential 

 and should be done by all nurserymen before their stock is sent out. 

 A few scales may easily escape detection and so set up a large 

 colony, to the detriment and even death of the tree. I know of no 

 district in England where this pest does not occur in greater or less 

 abundance. Old trees and neglected orchards chiefly encourage it, 

 but young stock suffer far more than old. 



This scale insect is frequently taken for growths on the bark. 



The scale is the product of a minute insect belonging to the 



