7 

 yielded 1.1 per cent scabby apples. In their dusting experiments, trees which 

 received sulfur yielded 2.6 per cent scabby apples and those which were dusted 

 with sulfur with calcium caseinate added yielded 2.4 per cent scabby apples. 



The claim is made that calcium caseinate spreaders improve the adhesiveness 

 of sprays, but it should be noted that Butler and Smith (14) found that the ad- 

 hesiveness of Bordeaux mixture is not affected by the addition of calcium caseinate. 

 Whatever may be said in favor of the use of calcium caseinate, and there are sound 

 arguments in its favor, it cannot be said that there is sufficient or satisfactory 

 evidence as to its increasing the fungicidal efficiency of Ume-sulfur against apple 

 scab to a point of commercial importance. It is probable, however, that the more 

 imperfect the sprajdng, the greater the benefit to be derived from the use of a 

 calcium caseinate spreader. 



Calcium caseinate is further considered in connection with its effect on com- 

 patibiUty of ingredients in combination sprays. 



Bordeaux Mixture as Compared with Lime-Sulfur for Applications 

 Before Flower Buds Open. 



The Bordeaux mixture used in these experiments was an excess-lime Bordeaux 

 mixture containing 3 pounds of copper sulfate and 10 pounds of Hme in 50 gallons 

 of water. This is referred to in the abbreviated language of practice as 3-10-50 

 Bordeaux mixture. It was used, rather than a Bordeaux mixture containing copper 

 suKate and Hme in the ratio 1:1, because it has been found to be somewhat safer 

 to the sprayed tree. 



In the preparation of Bordeaux mixture, the diluted copper sulfate solution and 

 the diluted milk-of-Ume may be poured together into a third barrel or into a spray 

 tank, and this is a method quite generally followed. But it requires some special 

 equipment and involves unnecessary labor. It is important . that at least one of 

 the stock solutions, either copper sulfate or hme, be diluted before the other and 

 concentrated one is added to it, but as Butler (15) has shown, it is not necessary 

 that both be diluted before mixing. In practice, it is sufficient to place the copper 

 sulfate stock solution in the spray tank when it is about three-fourths full of water; 

 then, with the agitator running, add the undiluted stock solution of the hme, and 

 fiU the tank with water. The Bordeaux mixture used in these experiments was 

 prepared in this way. 



In many experiments where Bordeaux mixture and hme-sulfur have been com- 

 pared, it has been found that the former has a somewhat greater fungicidal efficiency 

 than the latter against apple scab. Unfortunately, Bordeaux mixture usually burns 

 the fruit and fohage of the apple. The results of many experiments are weU illus- 

 trated by those of Krout (2) who found that even an excess-lime Bordeaux mixture 

 of 3-10-50 formula, when used for all appUcations, russeted the fruit and burned 

 the foliage severely. For this reason, the use of Bordeaux mixture throughout the 

 spraying season was not attempted in 1923. It was, however, used on certain plots 

 for the pink, or the prepink and pink apphcations, followed by Ume-sulfur for later 

 applications. 



The plot in the Frost orchard which received three apphcations of hquid hme- 

 sulfur yielded 2.1 per cent scabbj^ apples, while the plot which received Bordeaux 

 mixture for the pink application and hquid lime-sulfur for the calyx and last apph- 

 cations jdekled 1.7 per cent scabby apples. This is too small a difference to have 

 any significance. The plot which received the prepink and pink appUcations of 

 Bordeaux mixture followed by hquid hme-sulfur for the later appUcations yielded 

 0.6 per cent scabbj^ fruit. This reduction in the amount of scabby fruit cannot be 

 attributed entirely to the substitution of Bordeaux mixture for Ume-sulfur since 

 this plot received one extra application; namely, the prepink. The results in 

 Frost's orchard do not show that any benefit is to be derived from the substitu- 

 tion of Bordeaux mixture for Ume-sulfur for the early apphcation. 



At the Knights orchard, Bordeaux mixture was substituted for dry Ume-sulfur 

 in one case and for liquid lime-sulfur in another for the pink or prepink and pink 

 applications. The plot sprayed with dry Ume-sulfur throughout the season yielded 

 1.7 per cent scabby fruit, and the plot on which Bordeaux mixture was substituted 

 for dry Ume-sulfur at the time of the pink apphcation yielded practically the same; 

 namely, 1.06 per cent scabby fruit. No benefit from the substitution of Bordeaux 



