138 HORTICULTURE FOR SCHOOLS 



228. Spraying. Spraying is one of the most necessary 

 tasks the orchardist has to perform. To be successful he must 



know what insects or diseases 

 he is spraying for, and must 

 apply the spray at the proper 

 time and so that no parts of 



FIG. 97.-Pruning shears. ^ ^ ^ migsed 



229. Spraying machinery. Spraying machinery must be 

 of such construction that the spray can be applied rapidly 

 and effectively over the entire tree. There are many types 

 of spray machines, such as hand sprayers for small plants or 

 trees, knapsack sprayers for applying both liquid or dust 

 preparations, bucket pumps and power outfits. The latter 

 are the best for large orchards. A power outfit consists of a 

 tank to hold the spray, a pump which should be able to keep 

 up a high pressure, an engine for running the pump, an agi- 

 tator for keeping the spray in the tank mixed, a pressure 

 gauge and regulator for maintaining a uniform pressure and 

 a truck on which the outfit is mounted. All parts of the 

 outfit should be durable in construction, and the parts which 

 come in contact with the spray should be of some material 

 which does not corrode easily; for valves brass is best, and 

 for the tank wood is generally used. 



230. Nozzles and spray-rods. There are many kinds of 

 nozzles, some suited for general work and others for special 

 purposes. One of the most common is the disc type in which 

 the spray is forced out with a whirling motion through a 

 small hole in a disc. There are many types of needle-point 

 nozzles, in which a needle is so placed as to disengage the 

 material when the nozzle clogs. Needle-point nozzles are 

 now largely replaced with those of the disc type. Bordeaux 

 nozzles are of value for spraying coarse materials. 



A spray-rod consists of a hollow rod of some light material 

 through which the liquid travels from the hose to the nozzle. 

 The rods are of different lengths, depending on the size of 



