The European Elm Scale 23 



(4). It took the labor of three men to make the lime-sulphur 

 and to apply it, one at the boiling vat, one on the pump handle, and 

 one at the nozzle. Three men sprayed the elms once; and later, one 

 man washed off the female scales which escaped the three. If one man 

 had washed the trees three or four times, would that have cost more 1 

 Would it have been as effective? 



(5). Why not trim the elms in the winter, wash them with the 

 hard stream once in the spring just before the leaves appear, and 

 finally wash down at the end of May all the females which escape the 

 earlier treatment, omitting altogether the use of lime-sulphur or any 

 other insecticide? 



I can only answer, "It all depends upon the man behind the 

 nozzle." In all the experiments under discussion the Entomologist 

 was the man behind the nozzle. He had climbed the trees. He knew 

 just where the hibernating larvae lay hidden. He was not paying for 

 lime, or sulphur or for labor. He was perfectly willing to work his 

 spraying gang through a whole forenoon to spray four small trees. 

 It cost him nothing except when the doctor dressed his lime-sulphur 

 burns. 



The atmospheric conditions following these experiments are given 

 in the following tables : 



