46 DISEASES OF ECONOMIC PLANTS 



day were sprayed, making the labor cost 33 cents per acre. 

 Assuming that 100 gallons per acre were applied, the total 

 would be : — 



Copper sulphate, 6 pounds at 7 cents per pound . S .42 



Lime, 12 pounds at 1 cent per pound . . .12 



Total cost of material . $ .54 



Total cost of lal)or . . .33 



Cost per acre of each application $ .87 



Cost per acre of six applications 5.22 



" There should be added for interest on investment, 

 repairs, and depreciation of outfit, SI per acre, which 

 increases the total cost to $0.22 per acre." 



Spraying potatoes, tomatoes, or any other crop which 

 in like manner covers the ground costs approximately the 

 same. 



" The cost of treating pear, plum, and cherry stock the 

 first year, or before and after the buds are inserted, will be 

 about 25 cents for 1000 trees. The next year, or when the 

 buds are making their first season's growth, the cost of the 

 work will probably not exceed 25 cents, while the follo\ving 

 season or the second year from the bud, the cost will be 

 increased 10 to 15 cents, or about 40 cents per thousand. 

 On this basis the entire cost of treating trees until they are 

 two years old from the bud will range from $.85 to $1 per 

 thousand, or about 1 mill per tree." ' 



At Southern Pines, N.C., a careful account was kept 

 of the cost of treating grapes, including both material and 

 labor. The Bordeaux mixture cost almost exactly 50 

 cents a barrel. The labor was estimated as the work of 



' U. S. Dept. Agr. Div. Veg. Physiol. & Path. Bui. 7, p. 27. 



