22 BULLETIN" 805, TJ. S. DEPARTMENT OF AGRICULTURE. 



wood (Platanus deltoides). In addition, Wilson and Childs list 

 strawberry, logan blackberry, and prune from Oregon. It is likely 

 that this leafhopper will feed on the foliage of most plants belonging 

 to the family Rosaceae. 



CHARACTER OF INJURY. 



The nymphs and adults of Empoa rosae confine their feeding entirely 

 to the lower leaves of apple trees in the nursery. They congregate 

 on the lower surfaces of the foliage and suck the plant juices by 

 puncturing the leaf tissue with their tiny beaks. The first indication 

 of the injury is the mottling of the leaves with yellowish or whitish 

 spots at the points where the punctures were made. (See PI. IV.) 

 When the leaves become heavily infested they turn yellow, dry up, 

 and drop to the ground prematurely. The foliage is never curled by 

 this species, nor is the terminal growth checked, as in the case of 

 injury by Empoasca mali. 



A second type of injury is produced by the egg punctures made by 

 the females in the fall during the oviposition period. The eggs are 

 deposited under the bark of young apple trees, several hundred eggs 

 often being placed in a single twig. 



The injury produced by the rose leafhopper to apple nursery stock 

 is of little importance, however, when compared with that caused by 

 the more destructive apple leafhopper. 



DESCRIPTION OF STAGES. 



EGG. 

 PL V, B. 



The winter egg is elongate oval, slightly crescentic *n form, almost circular in cross 

 section, and blunt at both ends. It is almost transparent at first, but when ready to 

 hatch it changes to a milky white color, while the red eyes of the young nymph are 

 visible through the smooth chorion. 



Average length of 16 eggs 0.65 mm., width 0.19 mm. 



NYMPH. 



First instar. — Color of first-instar nymph pale white changing to light yellow after 

 feeding. Eyes dull red. Small spines present on the dorsal side of the head, thorax, 

 and abdomen; the latter with four spines to each segment arranged in two longitu- 

 dinal rows on each side. Posterior margin of metathorax blunt. First two segments of 

 antennse pale, remainder dusky. Average length of 16 specimens 0.98 mm. 



Second instar. — General color creamy white to light yellow. Eyes lose some of 

 their red color, becoming lighter. Wing pads begin to appear as lateral buds. Pos- 

 terior margin of metathorax sharp in outline. First two segments of antennae yellow, 

 remainder dusky. Average length of 16 specimens 1.27 mm. 



Third instar.— General color light yellow. Eyes dull white. Body more robust than 

 in first two stages. Wing pads extending to hind margin of the first abdominal seg- 

 ment. Spines darker and more prominent. Average length of 16 specimens 1.55 mm. 



