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THE APPLICATION OF CONCENTRATE SPRAYS 

 BY LARGE AIRBLAST SPRAYERS 



F.H. Lewis^ 

 Pennsylvania State University 

 Fruit Research Laboratory 

 Arendtsvi 1 1 e , Pennsylvania 



ON APPLES 



I would like to take my assigned topic of concentrate sprays 

 and expand the discussion to a consideration of the overall pest 

 control program on apples and the place that pesticide application 

 methods have in changes for the future. 



We have four major problems in the apple pest control field. 

 These problems, not necessarily in the order of their importance, 

 are (i) a continued need for new miticides and mite control pro- 

 grams, (ii) the concern of our customers and the government regard- 

 ing chemical residues, (iii) the cost of the pest control program, 

 and (iv) the labor problem, including cost, availability and skills 

 Concentrate sprays have a vital role in our plans for the solution 

 of all of these problems. 



Dean Asquith and I began work on concentrate sprays nearly 

 20 years ago. In the beginning, our interest was based primarily 

 on cost figures. A similar approach may be useful here. 



When a grower purchases a large airblast sprayer at about 

 $9600, the annual fixed cost of owning that sprayer will be about 

 $1500 for depreciation (10% of cost less 10% trade-in), interest 

 (7% on bank loan repaid in 10 years), fire insurance (60 cents per 

 $100 on the amount owed), and shelter (1% of cost of machine). 

 Many growers would use this machine no more than 200 hours each 

 year. The variable costs for 200 hours work are estimated at about 

 $600. This would include repairs, lubrication, gasoline and oil. 

 The labor cost is estimated at $2.50 per hour. Thus, if the spray- 

 er is used only 200 hours each year, the cost per hour for the 

 sprayer and one man will be about $13.00. This could be reduced 

 to about $10.00 per hour by using the sprayer about 400 hours each 

 year. These costs have gone up over 42 per cent in 6 years. 



It is necessary to have a tractor to pull the sprayer and a 

 good tractor for work on somewhat hilly land is apt to cost at 

 least $6000. If this tractor is used throughout the year, it may 

 cost no more than $2,00 per hour. The cost of the sprayer, tractor 

 and one man would then add up to $15.00 per hour for 200 hours 

 spraying each year and about $12.00 per hour for 400 hours spraying 



Assuming that the sprayer does not break down, the total time 

 in the orchard is spent in spraying, turning on row ends, and re- 



Talk presented by F.H. Lewis at fruit meetings in Maryland and 

 West Virginia. Printed with his permission. 



