236 SUCCESSFUL FRUIT CULTURE 



Remedy When the injury is upon the branches, 

 the application of soft soap or strong whale-oil soap 

 solution with a stiff brush will be effectual, or kerosene 

 if applied in a fine spray so that it will not stand in 

 drops on the foliage will be equally good. A bright 

 airy day should be selected that the kerosene may be 

 applied liberally and yet evaporate quickly if the trees 

 are in leaf. When the leaves are off it can be much 

 more freely used, and therefore the first or preventive 

 measures should be tried. Its presence on the roots of 

 young trees can only be determined by digging up one 

 or two trees. 



Plum Curculio (Conotrachelus nenuphar) This 

 pest, which is perhaps more destructive to the stone 

 fruits than to the apple, is seriously injurious to the 

 latter. It attacks the fruit in its young stage, making 

 the crescent shaped mark shown in Figure 126, in 

 which it lays its egg. These eggs do not mature in 

 the apple, but the fruit is disfigured and at the 

 punctured place often fails to grow, thus producing 

 gnarly and irregular fruit. 



Remedy See under the plum. 



INSECTS ATTACKING THE PEAR 



The Round-Headed Borer, Flat-Headed Borer, San 

 Jose Scale, Oyster Shell Bark Louse and Codlin Moth, 

 described as attacking the apple, are also injurious to the 

 pear, but the canker worm and apple maggot do not 

 attack it. Remedies for the above insects have already 

 been described. 



Pear Tree Psylla (Psylla pyricola) (Figure 125) 

 A minute, flat, yellow, aphis-like, jumping insect that 

 injures the trees by sucking the juice from the leaves 

 and young branches. Wherever the punctures are 

 made the juice exudes and a pool is formed in which 



