498 BULLETIN 333 



Paste arsenate of lead was used for the most part, at the rate of 3 pounds 

 to 50 gallons of water for the first application. For the second appli- 

 cation the proportion was 3! pounds to 50 gallons of water. On about 

 thirty-five trees powdered arsenate of lead was used, at the rate of ij 

 pounds to 50 gallons of water. 



In all there were on the university grounds about five hundred and 

 thirty trees that were sprayed in 191 1. About one hundred of these 

 were scattered over the steep hillsides west of the buildings and along 

 University and Stewart avenues. Many of the trees were nearly a mile 

 from the campus water supply, and the majority were scattered and not 

 easy to reach. Exclusive of permanent equipment, the cost of spraying 

 these trees twice was $464.90, or an average of approximately 88 cents 

 each. The scattered trees raised materially the average cost of the whole. 

 If all the trees had stood along streets and reasonably near a water supply, 

 the average cost, the writer thinks, would have fallen below 70 cents. With 

 the two machines it took ten days to make the first spraying and eleven 

 days to make the second. The second spraying was done more thoroughly 

 and there was much more leaf surface to be covered; on the other hand, 

 experience had made the men more efficient. The great majority of 

 the trees were over forty years old, while some were older; nearly all 

 of them were large. 



DETAILS OF COST OF SPRAYING ELMS ON CORNELL UNIVERSITY CAMPUS 1 



In order to give a clear idea of the cost of spraying elm trees, a few 

 details of the work on different days are here presented. The men were 

 paid $2 a day with the exception of the foreman, who was an experienced 

 man and who received $5 a day. The men who drove the teams and 

 sprayed the trees were inexperienced. The amount paid for teams was 

 $2 a day. 



On June 20 the two machines sprayed eighty-two trees, some of which 

 were small. The total expense of this day, including men, teams, arsenate 

 of lead, and gasoline, was $24.91, an average of 30! cents per tree. On 

 June 1 6 sixty-six trees were sprayed at a total cost of $22.14, an average 

 f 332 cents per tree; these were all large trees. On June 19 fifty-nine of 

 the largest trees on the campus were sprayed those along Central 

 Avenue southward from the Library. The cost of spraying these trees 

 was $23.965, an average of 40! cents per tree. These trees stood close 

 to the street and near a water supply. They are very large trees, 

 having a great amount of leaf surface. This should give one a fair idea 

 as to the cost of spraying the largest trees. 



1 Journal of Economic Entomology, vol. 5, no. 2, April, 1912, pp. 170-171. 



