The European Elm Scale 17 



oughly sprayed twice or even three times. Even at that, some of the 

 hibernating larvae hidden between the plates of cork escaped the 

 spray entirely. 



As the trees varied in size and in degree of infestation, they were 

 divided into lots ; and as the results varied somewhat, the different lots 

 will be discussed separately. 



LOT I 



Fifty-eight young cork elms in the park opposite the Court-house, 

 Eeno, Nevada. Trees twenty to twenty-five feet in height ; a few of the 

 higher branches were trimmed in order that the whole tree might be 

 covered with the spray. The trees were sprayed, inspected and re- 

 touched to cover spots missed in the first application. They were not 

 badly infested on the whole ; six showed evidence of serious injury in 

 September, 1906. llany were only slightly infested; others appa- 

 rently not at all. 



In the spring following the spraying, leaves appeared on these 

 trees one week later than on surrounding \inspraAed elms of the same 

 age. In June on some of the spra\'ed trees there were no small 

 number of mature females on the underside of some of the branches. 

 On one such tree which could scarcely have escaped a thorough spray- 

 ing in February, there were a great many females present on the lower 

 limbs late in the following June. These were all washed away with a 

 .strong stream of water from a garden hose; and the gardener was 

 instructed to follow the same plan with the remaining trees. A close 

 examination of the bark on September 16th, showed that few female 

 insects had escaped. On the leaves there were a few larvae. On 

 December 13th, after the leaves had all fallen, a most careful examina- 

 tion of those trees which had been most seriously infested in 1906 dis- 

 closed a few winter larvae in the axils of buds and leaf scars, or clus- 

 tered about the few remaining dead female scales. 



The total result of the treatment given the trees in Lot I was very 

 good. Throughout the summer their appearance gave no evidence 

 that the Elm Scale was present ; the foliage was dark green and glossy 

 in late summer in strong contrast to the prematurely yellow leaves of 

 the unsprayed trees. 



LOT II 



Ten trees at the corner of State and Center Streets, Reno. Nevada. 

 Cork elms, very rough and shaggy with cork, about twenty-five feet 

 in height. Slightly infested, with the exception of one, which showed 

 signs of serious injury in the late summer of 1906. Early in the sum- 

 mer of 1907, Mr. "Westerfield found some female scales on the under- 



