382 Fruit-growing in Arid Regions 



states. We hope that this immunity may be due to the inability 

 of the scale to thrive in the higher altitudes. 



The remedy for San Jose scale is the same as for the Howard 

 scale. 



SPRAY PUMPS AND SPRAYING 



Pumps with metal valves should be used for the appli- 

 cation of insecticides or fungicides in liquid form, as the 

 materials harden or decompose leather valves so that 

 they last but a short time. If bordeaux mixture is to be 

 used, all parts of pumps and nozzles that come in contact 

 with the mixture must be made of brass, as the chemicals 

 very soon destroy iron. Wooden tanks must take the 

 place of metal. If the pump is to be used with a tank or 

 barrel, it is also important to have some kind of attach- 

 ment that will keep the liquid agitated, so that the ma- 

 terials in suspension will not settle. A common error is 

 to purchase a pump of too small capacity, because it is 

 cheaper. A smaller, cheaper pump usually means less 

 accomplished in a day with the same help and a poorer 

 job, with a greater expenditure of labor. It is often im- 

 portant to complete the spraying in as short a time as 

 possible after it is begun. To do this, a pump of large 

 capacity with two or more leads of hose is necessary. 

 The hose to which the nozzles are attached should be as 

 light as possible and still have the requisite strength a 

 hose of good quality with heavy wall, but small caliber. 

 Bucket pumps are sold by different dealers at prices rang- 

 ing between about $2 and $8. They are suitable for use 

 among garden vegetables, shrubbery, and all low plants, 

 but should not be purchased for orchard work if one has 

 more than a very few trees to treat. 



