336 PEAR GROWING IN CALIFORNIA. 



CHAPTER XII. 



SPRAYING THE PEAR. 



Without systematic, regular and careful spraying for certain ever- 

 present diseases and insects, success in the pear business is impossible. 

 In the discussion of insect pests and fungous diseases, specific instruc- 

 tions are given for each pest. There are a few general principles 

 regarding spraying which are needed if one expects to get maximum 

 results. 



WHEN TO SPRAY. 



The question of when to spray can not be intelligently decided unless 

 the orchardist has a knowledge o'f the insects and diseases for which 

 spraying is necessary. In the case of certain pests, for example : 

 codling moth and scab, which are nearly always present, rules that 

 are subject to slight variations can be laid down, for spraying to 

 control these pests must be done with regularity and at approximately 

 the same time each season, at least the applications for these troubles 

 must be made when the trees are in a certain condition of their growth. 

 In the case of certain other pests, for example: red spider, thrips, 

 aphids and scale insects spraying does not need to be .done regularly 

 and whether or not the need exists must be determined by the owner of 

 the orchard to be sprayed. Preventive sprays for pests of this nature 

 which require contact insecticides for their control are not usually of 

 any value and the time to spray is determined only by a knowledge 

 of the presence of the pests at a certain time during the season. Thus, 

 while in the case of certain insects and diseases spraying becomes a 

 regular thing at approximately the same time each season, in the case 

 of other pests spraying is done only when conditions justify it. Intel- 

 ligent spraying means a fairly accurate knowledge of the pests and 

 their habits and a lack of such knowledge often means time and money 

 wasted in making untimely applications. 



THOROUGHNESS IN SPRAYING. 



There is nothing in connection with spraying work in general that 

 needs greater emphasis than the need for thoroughness in applying a 

 spray. Sprays either kill by contact or by poisoning through assimila- 

 tion after being taken internally. In the first case it becomes exceed- 

 ingly difficult to apply a spray in a thorough enough manner so that 

 every square inch of surface on a tree is covered. In the case of spray- 

 ing for sucking insects of all kinds it is absolutely necessary that no 

 portion of a tree be missed. Scale insects and aphids breed very 

 rapidly and failure to kill practically 100 per cent may mean a prac- 

 tical failure in controlling the pest. With these insects present to 

 spray for the work should be done by careful, trustworthy hands who 

 should be taught to exert every effort toward spraying so thoroughly 

 that no insect wherever present on a tree would be missed. Theoreti- 

 cally it would be possible to reach every one, practically it is not, and 



