452 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



The apple blotch frequently causes 

 over 90 per cent of injury to susceptible 

 varieties in the Central West. It has 

 been successfully controlled on the fruit, 

 the first season sprayed, by the applica- 

 tion of Bordeaux mixture. 



By the continued use of Bordeaux dur- 

 ing successive seasons the disease can be 

 almost completely eradicated from the 

 orchard in from four to six years. The 

 3-4-50 Bordeaux can be safely used, if 

 made and applied only as recommended. 



It is especially necessary in the con- 

 trol of this disease that the spraying be 

 done with absolute thoroughness, and 

 at the time indicated in the schedule. 



Lime-sulphur solution is less effective 

 than Bordeaux mixture, for blotch con- 

 trol, but should always be used during 

 wet weather, on account of the tendency 

 of Bordeaux to cause injury at such a 

 time. 



The work of eradicating the blotch 

 fungus can be hastened, the chance for 

 injury lessened, and the commercial 

 value of the fruit increased, by carefully 

 cutting back the affected trees. 



This cutting-back process strengthens 

 the framework of the tree, and throws 

 it into vigorous growth. Advantage may 

 be taken of this growth to increase and 

 lower the bearing surface of the tree. 



Recommendations 



The apple blotch fungus can be con- 

 trolled. In the most susceptible vari- 

 eties, showing an enormous amount of 

 cankers, the disease has been reduced to 

 less than five per cent of injury by the 

 application of Bordeaux mixture. It has 

 been found that the disease on the fruit 

 can be controlled the first season by 

 spray applications, and that by follow- 

 ing the same treatment during succes- 

 sive seasons it can be almost entirely 

 eradicated from the orchard. This pro- 

 cess can be hastened and the injury 

 materially lessened by removing the 

 worst cankered and useless limbs from 

 the infested trees. 



Bordeaux mixture frequently causes 

 serious burning, and an investigation of 

 the methods generally used in preparing 



this mixture has led the author to the 

 conclusion that three factors are largely 

 responsible tor this injury: First, a 

 stronger mixture than necessary to con- 

 trol the fungi is ordinarily used: sec- 

 ond, unsatisfactory methods are fre- 

 quently employed in mixing; third, a 

 poor grade of lime, or air-slaked lime, 

 is commonly used. Investigations both 

 in the laboratory and in the orchard 

 have shown that three pounds of copper 

 sulphate and four pounds of well-slaked 

 stone lime for each 50 gallons of water 

 make a Bordeaux which, for all summer 

 orchard work, is effective and less liable 

 to injure tender fruit and foliage than 

 that made according to the stronger 

 formultP. 



Tlie Correct Method of Making Bordeaux 



In order to make an effective Bor- 

 deaux, and one that is the least liable 

 to cause burning, the copper sulphate 

 and lime should be added each to one- 

 half the total required water, and these 

 two dilute solutions allowed to run to- 

 gether, in equal quantities, into a third 

 tank. There is nothing new about this 

 method, as it has been in use for years, 

 but ordinarily the beginner tries to les- 

 sen the time and labor involved in this 

 process, with the result that serious in- 

 jury follows. The manner in which these 

 two solutions are mixed may be varied 

 according to convenience, just so the two 

 are mixed in equal dilute quantities. 

 Very frequently, when small amounts of 

 Bordeaux are required, the two dilute 

 solutions are poured together into the 

 spraying tank by hand. When large 

 quantities are to be made, however, two 

 tanks, each large enough to hold a little 

 more than one-half the volume of the 

 spray tank, should be placed upon an 

 elevated platform at such a height that 

 they will drain into the top of the 

 spray tank. The two dilute solutions 

 are then made in these tanks and allowed 

 to run together through equal-sized 

 openings into the spraying tank. 



Much care should be taken in slaking 

 the lime used in Bordeaux mixture. It 

 should not be entirely covered with 



