PEAR GROWING IN CALIFORNIA. 



377 



FRUIT-TREE LEAF ROLLER (Archips argyrospila). 



Under certain conditions the leaf roller is one of the most destructive 

 pests of the pear. Its presence in the orchard may be recognized during 

 the winter season by little masses of brown-colored eggs, somewhat 

 circular in form and a quarter of an inch, more or less, in diameter. 

 The larvae feed on the foliage and young fruit, sometimes becoming 

 so abundant as to practically defoliate the trees. 



F'iG. 168. Eggs of fruit tree leaf roller, A7-chips 

 argyrospila. 



Control. 



Perfect control results from an application during the dormant 

 season of Formula No. 7. 



FROSTED SCALE (Lecanium pruinosum). 



This scale somewhat resembles the black scale but is larger, more 

 smooth in outline and is covered with a whitish frosty-like material, 

 from which it derives its common name. It has been known to do 

 considerable injury in pear orchards near the San Francisco Bay. 



Control. 



Use Formula No. 5, 6 or 7. 



GREEN APPLE APHIS (Aphis pomi). 



Young pear trees are sometimes affected by this species of aphis, 

 which is rarely seen on older trees. It is the connnon plant louse of the 

 apple, which it much prefers as a food plant. This is a small green 

 species, with a very characteristic odor, which enables one to detect 

 its presence and to identify it. 



Control. 



Use Formula No. 3 or 4. 



LESSER SHOT-HOLE BORER (Xyleborus xylographus). 



Pear growers sometimes find little holes at the base of buds or tun- 

 neled into the heart of branches. These are made by the adults and 

 larv£e of a very small black beetle, occasionally becoming quite de- 



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