81 



b. Fixed to Bark— 



1. Producing an ashy gray incrustation on the bark; scales round, and 

 gray and black — San Jose Scale (Aspidiotus perniciosus). 



2. Bark rough with mussel-shaped scales — Oyster-Shell Scale (Lepido- 

 saphes ulmi). 



3. Bark scurfy with white scales — Scurfy Scale (Chionaspis furfurus). 



c. Making Tunnels in the Wood — 



1. Large square-headed legless borer at or near the ground in tunnels, with 

 sawdust-hke excrement — Round-Headed Borer (Saperda Candida). 



The Round-Headed Apple-Tree Borer 



Fig. i3 — Saperdn Candida : a. larva, from side; 6. from above ; c. female beetle; 

 (/.pupa — all enlarged one-third. (From Chittenden, ) 



2. Large flat-heailed legless borer in upper trunk in tunnels with sawdust- 

 like excrement — Flat-Headed Borer (Chrysobothris femorata). 



3. Large larva in decaying wood — Eyed Elater (Alaus oculatus) and Rough 

 Osmoderma (Osmoderma scabra). 



d. Making tunnels between the bark and wood — 

 L Fruit Bark Beetle (Scolytus rugulosus). 



(e) White woolly patches on the twigs which are usually scarred — Woolly 

 Aphis (Schizoneura langera). 



(f) Green soft-bodied insects in clusters on young growths, and particularly 

 at ends of twigs, producing distortions — Apple Aphis (Aphis mali). 



P.P. Eng.-6 



