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The Fruit-Growers Guide-Book 



When once established it is practically impossible to 

 rid an orchard of this pest, and the best means is to guard 

 against its getting a start in the orchard. One method is 

 to have the apple trees worked on Northern Spy roots, as 

 this variety seems to be quite immune from serious attacks. 

 Nursery stock that has been puddled should have all of 

 the mud washed off the roots and then be thoroughly ex- 

 amined for signs of infestation. Fumigation with hydro- 

 cyanic acid gas will eliminate the insects which may be 



m 



i 



Characteristic galls produced on tree roots by the woolly 

 aphis. 



present. Where present on the tops of trees, they can be 

 disposed of with kerosene emulsion or black leaf sprays 

 applied with sufficient force to wash off or penetrate the 

 woolly covering. Black leaf is considered the most ef- 

 fective when used in the proportion of one gallon to 65 

 or 70. When trees are sprayed with lime-sulphur for the 

 eggs of green aphis, the woolly aphis is kept in check. A 

 band of sticky fly-paper or "Tanglefoot" wrapped around 

 the base of the trees will prevent the migrating young 

 from ascending the tree from the roots. 



