342 Plums and Plum Culture 



in the chicken yard. The chickens usually keep the 

 ground bare underneath the trees and also eat a con- 

 siderable number of the beetles and larvae which fall 

 to the ground. This is not an ideal way to grow plum 

 trees, however. 



The Plum-tree Aphis. — This aphis is sometimes 

 very troublesome. It attacks the young shoots, es- 

 pecially the under sides of the tender leaves, and sucks 

 out the juices until the leaves curl, the shoots wither, 

 and growth may be practically stopped. In extreme 

 cases young trees are even killed. 



It is difficult to control. Paris green and similar 

 poisons will not harm it, for the simple reason that 

 they are applied to the outside of the leaf, while the 

 aphis sucks its liquid food from the inside. Something 

 must be applied to the insect itself which kills it by 

 contact, or smothers it by covering or clogging its 

 breathing holes, or which effectually disturbs or dis- 

 lodges it. 



Tobacco water is one of the best of these contact 

 insecticides. Tobacco stems can be bought of all 

 seedsmen and dealers in horticultural supplies at rea- 

 sonable prices, usually about $1.50 a hundred pounds 

 or $20 a ton. These should be steeped in boiling water 

 to make a strong decoction, which should be vigorous- 

 ly applied to the insects with a sprayer. More than 

 one application will usually be necessary; but, if per- 

 severed in, this treatment will prove efficacious. 



Kerosene emulsion is very generally used, and 

 has many points of advantage. It is applied with the 

 usual spraying machines, unless one has at hand some 

 of the specially constructed sprayers for mixing kero- 

 sene with water. If the ordinary kerosene emulsion is 

 to be used, it may be made up according to the follow- 

 ing directions: Take one pound of hard soap (prefer- 

 ably whale-oil soap), two gallons of boiling water, and 



