NURSERY AND ORCHARD INSECT PESTS 



15 



senical sprays have no effect on them since it is impossible for them to take 

 poison into their stomachs. 



CONTROL. In the bearing orchard where the plant lice are injurious spray 



FIG. 16. Plant lice: 1, Winter eggs on twig- 2, lice on tip of 

 apple twig; 3, development of louse, enlarged 



FIG. 17. Plant lice; apples dwarfed due to plant louse injury. (After Talbert) 



