LAWSON : KANSAS ClCADELLID.i. 17 



the grape. The bulletins by Slingerland, Quayle, Hartzell and 

 Johnson fully deal with the damage and control of these forms. 



Leaf hoppers as a group do not seem to injure garden crops 

 seriously. But there are a few species that at times do serious 

 damage. Notably injurious here is Empoasca mail, which is a 

 serious pest of such crops as beans and potatoes. Here also 

 comes the injurj' to sugar beets by Eutettix tenelhis. The in- 

 jury by these species in this case, however, has to do with the 

 relation of leaf hoppers to plant diseases, and will therefore be 

 discussed under that head. 



In the cotton-growing region several members of the sub- 

 family Cicadellinse have been considered injurious to the cot- 

 ton, though Sanderson seems to doubt their having any effect 

 on the plant. The supposedly injurious forms here are Homal- 

 odisca triquetra, Aulacizes irro rat a and two species of On- 

 cometopia. Essig gives Cicadella atropunctata as injurious to 

 such plants as blackberry, grape, lemon, orange and raspberry. 



It can perhaps hardly be said that leaf hoppers are injurious 

 to shade trees. WTiile a large number of species normally live 

 on trees, and others at times may infest them, yet no really 

 serious injury seems to have been reported. Thus the members 

 of the genus Idiocerus are largely confined to willows, cotton- 

 wood and Crataegus. Cicadella hieroghjphica and its varieties, 

 many species of Macropsis and some species of Empoasca occur 

 on willow. Bijthoscopus apicalis is confined to honey locust. 

 Oncopsis dutinctus lives on walnut, a Scaphoideus on elm, Tij- 

 phlocijba hthiernji on hard maple. The nearest to real injury 

 to shade trees ever seen by the writer was observed on notic- 

 ing the decolored condition of the leaves of a young sycamore 

 tree. On examination the leaves were found to be heavily in- 

 fested by an Erythroneura, the damage being very similar to 

 that of the grape-leaf hopper to the grape. 



The damage to ornamental plants also is not very serious. 

 Few cases are recorded of any such damage. It is sufficient 

 perhaps here to note the work of the rose-leaf hopper which. 

 in parts of the country, seriously injures rose bushes, the dam- 

 age being similar to that on the apple by the same species. 

 The writer has noticed a few leaf hoppers in gi'eenhouses but 

 seemingly they are never present in large enough numbers to 

 demand attention. 



. 2 — Sci. Bui. — 3058 



