394 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



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which the water was carried to the tank by an inch pipe and pumped 

 directly into the underground system. Water was thus continuously 

 available at any of the 24 hydrants, and these were so placed that with 

 150 feet of hose any tree in the orchard could be sprayed. Under this 

 system there is no loss of time for refilling, and the cost of horses is 

 eliminated. 



The elements of cost in operating a portable power outfit are engine 

 fuel, labor, and team. This does not include the wear and tear on the 

 machine, which would be about equivalent whether stationary or in 

 motion. Estimating on the basis of an 8-hour day, the actual cost of 

 operation of a power sprayer, as experienced by the writer in southern 

 California, is as follows: fuel averages, 40 cents (gasoline at 15 cents a 

 gallon), labor, $4.00 (2 men at $2.00), team, $5.00; total, $9.40. Under 

 the pipe system the elimination of a team reduces the daily cost of 

 operation bj^ $5.00, or over 50 per cent. Moreover, the avoidance of 

 loss of time for refilling which is necessary with a portable outfit 

 doubtless would amount to at least two hours a day. and results in an 

 additional saving of more than $2.00 a day. The total cost of the 

 application under a pipe system would probably average about 75 

 per cent less than with a portable sprayer in orchards adapted to this 

 method. The total cost of the |-inch pipe system in our experimental 

 orchard was $105.50, or 9| cents per tree. The economy effected 

 during the first treatment more than paid for this cost. 



This system of piping was installed for the use of a pure water 

 spray, but it became apparent to the writer that such a system offered 

 great possibilities in the field of fungicide and insecticide spraying. 

 A part of this orchard was successfully treated with distillate emulsion 

 and with soap powder through the pipe system. Doubtless such 

 sprays as lime-sulphur, nicotine and soap which do not require constant 

 agitation before application could be readily used through long leads 

 of pipe. Where a large acreage of plants requires treatment with such 

 sprays, the installation of a suitable pipe system is likely to prove 

 economical wherever the topography of the ground permits. Further- 

 more, this system covers fields of insecticide application which have in 

 the past offered almost insuperable obstacles, namely, the treatment 

 of truck crops on mucky land, or orchards on steep hillsides. 



A system of piping adapted to each case should be worked out before 

 attempted installation, and certain pertinent suggestions gained during 

 our experimental work might be worth mentioning. The capacity of 

 the pump of the average power sprayer (about 10 gallons a minute) 

 is not adequate for a large pipe system though it would suffice for a 

 few acres where not more than two or possibly four mist nozzles are to 

 be used. To determine the capacity of the pump Avhich should be 



