TREATMENT OF DISEASES INJURIOUS TO ORCHARD CROPS. 77 



the pressure may go down before the spraying is completed. A pressure 

 gauge shows the driver when the pressure is low, and he immediately 

 operates the accessory hand-pump till the tree is sprayed. 



Steam spraying outfits are being used in the larger orchards and also by 

 the park departments of cities and towns with satisfactory results. Some 

 of these are fitted simply with steam pump, and depend upon horse-power, 

 taken by means of sprockets on the wagon wheel, for running the agitator. 

 Others have an engine, which runs both the pump and the agitator, 

 mounted on the wagon which carries the pump. Some use kerosene 

 or gasoline for fuel, others burn coal. 



One of the recent designs in spraying apparatus which is worthy of 

 notice provides for the use of compressed air for spraying. Upon a two- 

 wheeled cart is mounted one tank for holding the compressed air and 

 another for the Bordeaux Mixture, the two being connected with 

 J-inch pipe. A steam gauge shows the amount of pressure. When 

 a spray is desired a valve is opened so that the compressed air forces the 

 Bordeaux Mixture out in a fine spray. The amount of pressure admitted 

 to the liquid is regulated by the extent to which the valve is opened. 

 One horse takes the spray cart even over rough hillside vineyards without 

 upsetting, and the spray continues uniform regardless of the position of 

 the liquid in the tank. No agitator is used, and if the spraying is 

 uninterrupted and the mixture properly prepared none seems to be needed. 

 The outfit consists of two carts like the one described and a gasoline 

 engine and air pump for supplying the compressed air. "While one cart 

 is being used the tanks on the other are being filled, one with compressed 

 air and one with the Bordeaux Mixture, so that on the return of the first 

 cart the second is ready to be used. The engine and air pump are 

 mounted on a one-horse wagon so that they may readily be moved to any 

 place most convenient to the field of operations where water for the spray 

 mixtures may be obtained. This outfit gives the owner excellent satisfac- 

 tion. It does the work well and easily. So far as I know, no apparatus 

 of this kind has yet been put on the market by any manufacturing 

 concern. The owner has purchased the various parts and constructed the 

 apparatus himself. This device is doubtless the forerunner of a new^ 

 type of spraying apparatus for orchard use in which compressed air tanks 

 will supplant spray pumps. The idea of using compressed air for spraying 

 is not new. Some years ago apparatus for vineyard use were put upon 

 the market in France, but the machine which has been described above 

 is the first compressed air sprayer which I have seen constructed in 

 America for orchard use. It will commend itself to the commercial 

 orchardist because it does away with the labour of working a spray pump. 



Orchard Diseases not yet Controlled by Spraying. 



One class of orchard troubles should perhaps be mentioned in closing, 

 namely, those diseases for which no remedy is as yet known. 



The Peach Yellows disease continues to claim its viptims, while the 

 cause of it is still a mystery. The only treatment recommended is the 

 immediate destruction by fire of the afiected trees. Another Peach disease, 

 which in some orchards is even more destructive than the Yellows, is called 



