Soo BULLETIN 333 



A careful and detailed record was kept of the actual cost of spraying 

 four hundred and thirty-five trees. Most of these trees were large and 

 all stood near the street and near the campus water supply. The cost 

 of spraying these trees once was $133.37, or 30.7 cents per tree. On the 

 average, each machine sprayed 36 J trees per day of eight hours, or 4! 

 trees per hour, or a single tree about every 13 J minutes. The average 

 quantity of liquid used for each tree was approximately i8| gallons. 

 With the bordeaux nozzle, or with any nozzle throwing a coarse stream, 

 considerable liquid is sure to be wasted. Nevertheless, the writer thinks 

 it is not wise to try to be too economical in the use of the spraying material. 

 Both the upper and undersides of the foliage should be covered, even 

 if some material goes to waste in getting about among the branches. 



During the season of 1912 the beetles were not so abundant nor so 

 injurious. They appeared considerably later in the spring than in 1911. 

 No beetles were seen on the trees until May 1 7 and they were not abundant 

 until May 22. Spraying was begun on June 13 and finished on June 22. 

 This was a little later than usual, it having been decided to spray but once 

 because of the scarcity of beetles and because of the thorough spraying 

 in the preceding year. It cost $218.90 to spray the trees in 1912, an 

 average of 41 J cents per tree. Since only one application was given, the 

 work was done somewhat more thoroughly than before and considerably 

 more liquid was used. The men on the towers were paid $2.50 a day, 

 an advance of 50 cents over the amount paid in 1911. 



Powdered ar senate of lead, at the rate of ij pounds to 50 gallons of 

 water, was used on one hundred and twenty-six trees. It gave as good 

 results in controlling the beetles as did the paste, and mixed a little more 

 readily with water. It was slightly more expensive than the paste. 



COST OF SPRAYING SHADE TREES IN OTHER LOCALITIES 



It has been shown that in the work at Cornell University the cost of 

 spraying each tree was about 30 to 41 cents when one application was given. 

 It is probably safe to say that the shade trees of most towns and cities 

 could be efficiently sprayed at this cost. It must be remembered that 

 the trees on the Cornell University campus were being sprayed by an 

 entomologist who was anxious that the work should be an unqualified 

 success, at least so far as controlling the beetle was concerned. Great 

 pains were taken to coat all parts of the trees, especially the topmost 

 and the inner branches. In order to do thorough, careful work, much 

 time and material must be consumed. Undoubtedly the trees were more 

 thoroughly sprayed than are average trees. It would be easy to cut the 

 cost of spraying one fourth or one third by slighting the work. 



