110 FRUIT-GROWING 



With the present practice of using lime sul- 

 phur solutions in a very strong mixture for 

 winter spraying we have no trouble in killing 

 even the eggs of the oyster shell scale, although 

 the old method of using a more dilute solution 

 for the San Jose scale often allows the native 

 pest to escape destruction. (The various in- 

 secticides will be mentioned only briefly in con- 

 nection with the insects but will be taken up in 

 some detail later.) 



The plant lice are often troublesome in ap- 

 ple orchards. There are three common forms, 

 popularly known as the grain aphis, the green 

 apple aphis and the rosy aphis. The first one 

 is a frequent cause for alarm when it first ap- 

 pears on the opening buds in the spring. At 

 this stage in its life-history it is almost impos- 

 sible to distinguish it from its relative, the 

 green aphis. One year our trees in one end of 

 the orchard were simply covered with this pest 

 and we sent a hurry-up call to the city for all 

 the nicotine sulphate that we could get, this 

 being the standard remedy for all plant lice. 

 Before the material reached us the aphids had 

 entirely disappeared, having gone back to a 

 neighbor's grain field from whence they had 

 migrated the fall before. 



The aphids mentioned pass the winter on the 

 twigs of the trees in the form of small, oval, 

 shining black eggs. Commercial lime sulphur 



