INSECTS PECULIAR TO THE PEAE 143 



the bark, should be rubbed off by a hard brush with 

 soap and water and sand. 



For the numerous caterpillars and larvse which 

 attack the pear tree there is one very simple and 

 practical remedy, viz. the finger and thumb. The 

 ' aphis,' which is a common pest to all fruit trees, must 

 be very narrowly watched in the spring as soon as the 

 young leaves are developed, and should be treated with 

 the following mixture : — Boil four ounces of quassia 

 chips in a gallon of soft water until the bitter principle 

 has been extracted, the time required being from 

 twenty-five to thirty minutes ; in this mixture dissolve 

 at the time of application four ounces of soft soap to the 

 gallon, and apply hot if possible (up to 150° will not 

 hurt the tree); but if it is inconvenient to use hot 

 water, cold will answer the purpose. If trees have been 

 severely attacked by aphis they should be washed during 

 the winter with the above mixture. 



The American blight (Aphis lanigera) is peculiar to 

 the apple, and is destroyed by the above mixture. On 

 the branches of two years and upwards an application 

 of petroleum and milk will be useful, but the bark must 

 be quite sound at the time of application. Vinegar is 

 very destructive to this insect, probably the more adul- 

 terated the better ; it is easy to apply and to obtain. 



If the aphis descends to the roots, soot should be 

 applied. 



The pear is often attacked by a disease which has 

 the effect of rendering the bark rough and scaly, pre- 



