32 The European Elm Scale 



lime. In December, 1907, I examined two young elms which were 

 literally covered with hibernating larvae. Dead females were com- 

 paratively scarce. The owner of the elms said that it was useless to 

 wash the trees, that in the summer he had washed away the female 

 scales and, "Now, just look at them!" I asked, "When did you wash 

 them?" He replied, "In July or August, I have forgotten which." 

 He had washed away the almost empty females when the young were 

 nearly all out on the leaves. Had he used the strong stream twice 

 on those elms, once in April, just before the leaves began to show, 

 once in June before the young scale insects appeared, his trees would 

 have been comparatively clean in the following winter; and this at no 

 expense, for he had enough hose to reach the elms from all sides and a 

 nozzle which threw a powerful jet twenty feet in the air. 



There is but one generation of Gossyparia spuria each year. If 

 all the females could be destroyed at the beginning of the season 

 there would be no generation. 



In every stage of its growth Gossyparia spuria can be washed from 

 the bark readily with a strong jet of water. I have searched the winter 

 larvae out of cracks and crevices with the strong stream ten feet from 

 the nozzle. I have knocked females and their semi-cocoons out from 

 between plates of cork on elm branches leaving no trace of insect or 

 semi-cocoon. I have stood on the ground and washed away winter 

 larvae from branches twenty feet above. 



In this work the following apparatus is very useful : One hundred 

 feet of three-quarter inch garden hose with tight connections at all 

 joints, six feet of half-inch galvanized pipe with pipe-to-hose connec- 

 tions at both ends to one of which is attached a nozzle which throws 

 a hard, strong jet of water. For the lower branches the hard stream 

 may spread a little. For higher branches a long tapering nozzle 

 whose single, round opening throws a powerful, round jet is very suit- 

 able. 



THE AXE, THE GRUBBING HOE, THE PRUNING SAW AND 

 THE GARDEN HOSE 



These are the tools which we expect to use in our futui-e experi- 

 ments in controlling the European Elm Scale. 



We do not expect to use the axe as thoroughly as we would like. 

 No finer program for future Arbor Days in this vicinity could be 

 chosen than the cutting down of half the elms and other trees- along 

 our streets for the sake of the other half. Along State and Mill Streets 

 in Reno, half the elms should be sacrificed immediately. Some people 

 seem to think that the elm is a hedge plant instead of a tree. Often 



