Page S2 



BETTER FRUIT 



February 



THE PEACH BORER AND ITS WORK. 

 T]ie "borer" and its cocoon at root crown of two-year-old peach tree 



we believe to be undesirable, with 

 nothing to commend it. 



In the application of any concentrate, 

 either home-made or commercial, it is 

 essential that a definite method of dilu- 

 tion be followed. Two solutions may 

 look exactly alike and yet differ widely 

 in density, so that any accurate method 

 must be based primarily on the density 

 of the concentrate that is being diluted. 

 Moreover, we believe that recommenda- 

 tions based on the density of diluted 

 spray are preferable to those based on 

 the number of dilutions, even when 

 accompanied by a statement of the con- 

 centrate's density. 



Accurate dilution is very simple and 

 easily accomplished with the aid of a 

 hydrometer having the specific gravity 

 scale. Sprays of any desired density may 

 be obtained from any concentrate by 

 simply getting- the reading of the con- 

 centrate and dividing the decimal of this 

 reading by the decimal of the, spray 

 desired. For example, if the reading 

 of the concentrate is 1.27 (about 31° 

 Beaume), to get a spray of 1.03 density 

 we divide the .27 by .03 and obtain nine, 

 which is the number of dilutions required, 

 and which, of course, is obtained by add- 

 ing eight volumes of water. In this we 

 are simply applying the general fact that 

 the densities of solutions heavier than 

 water vary inversely with the number of 

 dilutions. 



This method gives final sprays of 

 definite density, and the importance of 

 this is obvious when we consider the 

 relatively small margins between safe 

 and unsafe densities in the use of these 

 solutions on foliage. 



With Beaume hydrometers the dilu- 

 tions are obtained indirectly either by 

 conversion into the specific gravity scale 

 or by means of a special dilution table. 

 In the latter case, however, a table is 

 likely to be needed for each density of 

 spray desired. 



The following table gives the uses of 

 the lime-sulphur spray as far as our 

 present knowledge extends: 



While it is believed that the densities 

 recommended in this table will generally 

 prove efficient and safe where pure solu- 



Density 



1.03 for regular annual control; 1.04 

 in bad cases, especially on old 

 apple trees 



1.02 



1.03 to 1.04; the latter strength for 

 aphis eggs (Col. Bull. 133:27) 



1.01; may be varied by .002 or more 

 either way, as results direct 



1.01, or slightly weaker 



1.003 to 1.005; may be varied .001 

 either way, as results direct. On 

 peaches and plums, limited trials 

 only, testing effect on foliage by 

 applying to a few trees several 

 days before regular applications 



tions are used, yet occasional injury has 

 occurred from third and fourth applica- 

 tions when the earlier applications of the 

 same strength of spray had proved 

 entirely safe. The presence of salt in 

 some of the commercial preparations 

 makes caution desirable in using them 

 upon foliage. Also, the abundance of 

 the application may frequently afifect the 

 amount of foliage injury nearly as much 

 as the density of spray applied. 



As compared with our other leading 

 sprays, the advantages of the storable, 

 home-made lime-sulphur are conspicu- 

 ous. In total cost, including the making, 

 it will produce a 1.03 scale spray for 

 about three-fourths of a cent, or less, per 

 gallon, while the commercial prepara- 

 tions usually cost two cents or more. 

 The known absence of superfluous, and 

 possibly harmful, ingredients is also of 

 some importance. For apple scab it does 

 not "russet'' the fruit; it can be made 

 up beforehand, and in proper strengths 

 costs about one-quarter of a cent per 

 gallon. Bordeaux (4-4-50), on the other 

 hand, russets fruit, is not storable and 

 costs about one-half cent per gallon. 



Insect or Disease 



San Jose scale 



Oyster shell scale 



Blister mite 



Plant lice eggs 



Peach leaf curl 



Apple and pear scab 



Apple worm (add arsenical 

 (2) and (3) 



Cherry leaf spot 



Peach scab and brown rot of 

 stone fruits (experimental as 

 yet) 



Spraying Times 



Trees dormant, but best in fall 

 or spring 



At hatching time 



Just before buds open. 



(1) Blossoms beginning to show 

 pink 



(2) Within a week after petals 

 fall 



(3) About three weeks later.... 



Three sprayings, a month apart, 

 beginning with signs of infec- 

 tion 



(1) Three or four weeks after 

 petals fall 



(2) Half way between (1) and 

 (3) 



(3) Two weeks before fruit ripens 



PROFESSOR W. M.. SCOTT, DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C, 

 SPRAYING IN HIS PEACH ORCHARD AT SLEEPY CREEK, WEST VIRGINIA 

 The "Friend" power sprayer being used 



