25 



and allow to stand the same length of time. Repeat the oper- 

 ation again, after which drain and dry the bine powder which 

 is copper carbonate." 



FORMALIN. — Formalin is nsed in general practice for rid- 

 cling eertain tubers of the seab fnngus and for treating tobáceo 

 seed beds after the seed is sovvn as a preventive of the damping 

 off ñmgus. Also see Formalin page 19°. 



For treating seed tubers, take one pound or °5 kilo of the 

 formalin to thirty gallons or 114 litres of water and soak the 

 tubers in the solution for two hours. They should then be 

 spread out to dry. For treating tobáceo seed beds, dilute one 

 pound or .5 kilos of the formalin with twenty five galolns or 95 

 litres of water. Apply to the seed bed before the seed is sown 

 allowing the soil to dry two or three days before the sowing. A 

 sprinkling pot may be used for the preparation and the liquid 

 applied at the rate of one gallón or 3.8 litres to 1 to 2 square 

 feet or .1 to .2 sq. metres of space. 



SPRAYING APPARATUS 



As the selection of the spraying material depends upon the 

 eharacter of the pest to be combated, so the apparatus to be 

 used depends upon the plant and área to be sprayed. It is not 

 economy to buy a large heavy sprayer for the theatment of a 

 small garden of plants, ñor to attempt the treatment of large 

 plants or extensive áreas with a small hand machine. The follow- 

 ing discussion of the different classes of sprayers is intended 

 to assist persons inexperienced in spraying to decide upon the 

 most eoonomical machine for the work they may have on hand. 



POWER SPRAYERS.— The term power sprayer is used to 

 desingnate that class in which the pressure is generated by some 

 means other than hand labor. At the present tigie there are four 

 general classes of machines of this type. / 



With the first class the power is furnished by high pres- 

 sure tubes of carbonic acid gas. These tubes are filled at the 

 central manufacturing plaut-ánd shipped to the user. Where 



