244 THE SPRA YING OF FRUITS. 



greater in proportion as the other care of the plantation is 

 efficient, for the value of the product is thereby heightened. 

 Many old and neglected orchards are scarcely worth the 

 trouble and cost of spraying. The operation of spraying is 

 not always necessary, and it does not, therefore, always give 

 beneficial results. Unless insect or fungous troubles are 

 present, there is no occasion for the operation; but inasmuch 

 as these enemies are nearly always troublesome, and as no 

 one can definitely prognosticate their absence, spraying comes 

 to be an insurance. The risk is too great to allow the practice 

 to be omitted in any year in apple and some other orchards ; 

 and the practice is efficient only when it anticipates the 

 trouble. 



The amount of spraying which shall be done in any par- 

 ticular case, as well as its kind and seasons, depends entirely 

 upon the conditions and the enemies which it is desired to 

 reach. The operator must first of all make a diagnosis of 

 what his trouble is or is likely to be. If fungous troubles are 

 present, or are likely to be, some of the compounds of copper 

 or sulphur must be used. If leaf-eating or chewing insects — 

 like canker-worm, codlin-moth larva, bud-moth larva, tent- 

 caterpillar — are at work, some arsenical poison is to be used. 

 If scale-like or lice-like insects — as bark-louse, San Jose 

 scale, aphis — are present, soap, oil, or emulsion should be em- 

 ployed. In some fruits the operator can prognosticate given 

 troubles with tolerable certainty. For instance, it is safe to 

 assume that the apple will be attacked by the scab-fungus — 

 except in very dry regions — and by the codlin-moth larva. 

 Bordeaux-mixture is a specific for the former, and Paris- 

 green for the latter. These materials may be combined and 

 applied together with as good results as if each were applied 

 separately. As a rule, two insurance sprayings are advised 

 for the apple-orchard, the first one just as the blossom buds 

 have opened, but before the flowers themselves have begun 

 to expand, and the other about as soon as the last petals have 

 fallen. The grower must determine if more sprayings are 

 needed. If insect or fungous enemies are threatening, spray 

 again. The fungous diseases are commonly most serious in 

 wet seasons. As a general rule, the^re. should be two spray- 

 ings for codlin-moth larvae on the apple and pear (the apple- 



