PLANT-LICE INJURING THE FOLIAGE 



319 



To control, spray with tobacco extract or with kerosene emulsion 

 as soon as the lice are first seen. 



The Currant Aphis {Myzus ribis Linn.) 



Like most other plant lice this species causes a curling up of the foliage 

 infested. Both currants and gooseberries are subject to attack. The 

 leaves curl tightly, and their upper 

 surfaces show chstinct raised areas or 

 blisters, between the veins. 



The lice are one twelfth of an inch 

 long, mottled green, and have red 

 eyes. The pest passes the winter as 

 shining eggs, attached to the woody 

 parts of the plants. 



Contact sprays, such as tobacco ex- 

 tract or kerosene emulsion, will kill 



them, but should be appUed before 

 the leaves are badly curled. 



Fig. 490. —Work of the Currant 

 Aphis. Original. 



The Grapevine Aphis {Macrosiphum viticola Thos.) 



Dusky, soft-bodied plant lice with greenish legs cluster on the tender 

 leaves and young shoots of grapevines. They appear in the early part 

 of the season, and usually are not noticed after growth is well established 



Fig. 



491. — Work of the Grapevine 

 Aphis. Original. 



Fig. 492. — The Grapevine Aphis. 

 Greatly enlarged. Original. 



