146 



FRUIT INSECTS 



are often necessary to thoroughly control these prolific little 

 pests. Usually the weather conditions in the spring, aided by 

 the insect enemies, prevent serious injury by the aphids on large, 

 bearing trees. When they do infest such trees in destructive 

 numbers and swarm on to the young fruits, the tree should be 



Fig. 158. — Plant-lice rhisteni 



lilt. 



promptly and most thoroughly sprayed with one of the insecti- 

 cides mentioned above. Such sprays applied in October would 

 kill many of the sexual forms before the eggs are laid. Nursery- 

 men especially could thus strike a very effective blow at these 

 plant-lice and often prevent much of their destructive work 

 the next season. 



