CONTROL OF THE HOP APHIS. 35 



one full air bottle to each tank of spray. However, the same bottles are charged 

 several times in a day, and on some ranches we run 10 or 12 spray rigs with three dozen 

 bottles, and could probably get along with a few bottles less, if necessary. 



The air compressor we use is a 10 by 12 double-acting mine compressor with the 

 valves removed from one end . The piston rod is continued on through and the initial 

 compressor puts the air through pipes immersed in water that cool same, and the ram at 

 the other end of the piston rod puts this air up to 1,000 pounds. We use XX f-inch 

 steel pipe for leads, and usually fill three or four bottles at a time, or new bottles can 

 be put on and others taken off, without stopping the compressor. The compressor we 

 have designed will charge about 25 bottles per hour, if necessary, all from 1,000 to 1,200 

 pounds. Lately we are charging quite a lot at 1,200 pounds, especially where we use 

 250-gallon tanks. Cost of compressor, as fitted, $550. 



For small growers it would seem to us that they could club together and buy a com- 

 pressor and bring their empty air bottles in for recharging, as a bottle gets away with a 

 lot of spray even at high pressure. The reducing valves are so constructed that any 

 pressure desired is obtained. We have also tried the use of carbonic-acid gas for spray- 

 ing, but we use the spray material up so fast that the gas freezes itself up in the valve 

 while coming out of the bottle when the pressure is being reduced. This could be 

 overcome by the use of an alcohol lamp in the lead line, but this is too cumbersome; 



besides, air costs less. 



E. Clemens Horst Co.. 



By Theo. Eder. 

 COST OF SPRAYING. 



The following estimate of the cost of spraying for the hop aphis is 

 made from data taken from actual field work on high-trellis yards. 

 The amount of material needed for hops on short poles will be some- 

 what less. 



It has been found that one machine will spray from 2 to 3 acres 

 per day, and that in order to do thorough work it is necessary to 

 apply from 300 to 500 gallons per acre according to the amount of 

 foliage on the vines. The following data are based upon a machine 

 which will spray 2 acres per day : 



Materials: Nicotine sulphate, 1-2,000; flour paste, 4-100. Cost, 70.8 cents per 100 



gallons. 



300 galls. 500 galls. 



Applying per acre $2. 13 $3. 54 



Labor, 3 men, $2 per day for § day 3. 00 3. 00 



1 horse, 50 cents per day for £ day , 25 .25 



Total cost per acre of 1 application ' 5. 38 6. 79 



Quassia and Whale-Oil Soap. — Formula No. 2. 



Cost of materials per 100 gallons $0. G9 



Cost of cooking 11 



Total 80 



300 galls. 500 galls. 



Applying per acre $2. 40 $4. 00 



Labor, 3 men, $2 per day for \ day 3. 00 3. 00 



1 horse, 50 cents per day for \ day 25 .25 



Total cost of 1 application 5. 65 7. 25 



