SMALL, ACTIVE INSECTS INJURING THE FOLIAGE 3138 
means of control consists in spraying thoroughly with tobacco extract 
as soon as nymphs appear. The spray must be directed to the under 
side of the leaves and must be applied before the insect has reached the 
winged stage, in order to be 
effective. 
The Apple Leaf-hopper 
(Empoasca mali Le B.) 
A very small whitish insect, 
winged and active in its ma- 
ture stage, swarms on the 
leaves of apple trees and some- 
times on other foliage, suck- 
ing the juice of the leaf. The 
feeding punctures cause tiny Fic. 480.— Work of the Apple Leaf- 
white spots, which in time be- BRppeh. “ORGS. 
come numerous enough to give the foliage a distinctly bleached ap- 
pearance. On young trees, and especially on nursery stock, the at- 
tack usually results in a curling of the 
tender leaves, somewhat resembling 
the work of plant lice. The insect 
winters partly as adults in rubbish, 
partly as eggs in the bark of the 
trees. There are several generations 
in the course of the summer. 
In orchard trees spraying with a 
Fic. 481.—The Apple Leaf-hopper. 
Enlarged and natural size. Orig- . ‘ 
eral extract, will Kill many of the leaf- 
contact insecticide, such as tobacco 
hoppers if the material is applied 
early in the season, before the winged stage appears. On nursery 
stock a desirable preventive measure is dipping in soap solution. 
The Pear Psylla (Psylla pyricola Foerst.) 
The pear psylla is a minute, sucking insect, wingless in its immature 
stages, but active and winged as an adult. It sucks the juices of the 
