20 



FARMERS BULLETIN 



Fig. 21.— Horse-driven air-power sprayer in use in a potato field. 



example, are the best. The spray produced should be iii the form 

 of a fine mist covering every part of the plant. 



For truck gardens the common compressed-air sprayer employing 

 a tank holding 3 or 4 gallons and provided with a pump for develop- 

 ing the air pressure is the most effective type. An automatic cut-off 

 in the spray rod retains the liquid in the tank until the desired pres- 

 sure, as high as can be conveniently pumped, has been obtained. 

 Then the liquid may be released as required. Such a machme costs 

 $5 to $6 in galvanized iron, or $8 to $10 in brass. The latter is pref- 

 erable, as it lasts longer and is less liable to corrosion by the chemicals 

 used in spraymg. (See fig. 22.) A smaller t)^e known as the s}Tinge 

 atomizer, holding about a quart of spray mixture, and costmg from 

 50 cents to $2, according to construction, may be obtauied from most 

 seedsmen, and is suitable for small kitchen gardens. 



HOW TO PREPARE BORDEAUX MIXTURE. 



Bordeaux mixture is the only fungicide that has any practical 

 value against potato diseases. Lime-sulphur, powdered sulphur, and 

 other new mixtures that have come into use in orchards are injurious 

 to the foliage, or weaker in fungicidal action, or both. Tlie experi- 

 ments to date show that for potatoes and other truck crops nothing 

 has yet been found to replace the copper fungicides. The mgro- 

 dients and method of preparation are as follows: 



Copper sulphate pounds. . 4 



Quicklime do 4 



Water to make gallons. . 50 



Prt^pare the copper sulphate by suspending it in a gumiy sack just 

 below the surface of several gallons of water in a clean barrel. WTien 



