in the Baldwin orchard was there enough black-rot to enable us to secure any 

 information as to relative efficiency of the several treatments in controlling 

 this disease. In this orchard 7.2 per cent of the fruit on check trees, 2.0 per 

 cent of the fruit on the plot dusted with copper dust followed by sulfur dust, 

 and an average of 0.9 per cent of the fruit on all plots dusted with sulfur dust 

 showed black-rot infection. The infection on the check was of course light, but 

 we have some indication of the protection against black-rot given by the dust 

 treatment. 



Cost op Dusting and Spraying. 



This includes the cost of materials and the cost of labor, but not the cost of 

 equipment. The cost of treatment for one tree for the season is given in Table 

 IV. 



The labor involved was performed by two men and two horses at each 

 orchard, except Middlesex Fruit Farm where but one horse was used. Further 

 details as to size of trees and labor are given under the section on "Methods 

 and Materials." 



On the Gravensteins of the Middlesex Fruit Farm, 690 gallons of liquid and 

 seven hours of labor were required to spray 100 trees. To dust 100 Baldwins 

 here required 50 minutes and 127 pounds of sulfur dust. At Harvard Fruit 

 Farm, 100 trees were sprayed in two hours, using 160 gallons of liquid. One 

 hundred trees of this size were dusted in 33 minutes, using 75 pounds of sulfur 

 dust. At Pine Crest Orchard, 100 trees were sprayed in two and three-fourths 

 hours, using 360 gallons of liquid. One hundred trees at this orchard were 

 dusted in 35 minutes, using 110 pounds of sulfur dust. 



Although liquid lime-sulfur was not used at Harvard Fruit Farm or Pine 

 Crest Orchard, it is also included in the record of costs for purposes of com- 

 parison. 



A study of Table IV makes it evident that our cheapest method of protec- 

 tion is to spray with liquid lime-sulfur. Dry-mix sulfur-lime is more expensive, 

 although the difference is not so great if dry rather than liquid lime-sulfur 

 is considered. Bordeaux mixture is intermediate in cost between dry and liquid 

 lime-sulfur. Use of the spreader necessarily increases the cost. 



As to whether sprajdng or dusting is cheaper depends on the facilities for 

 spraying, the distance from the water supply, the size of the spray tank, the 

 size of the trees, and how many applications of dust are considered necessary. 

 Five applications of dust were enough in 1924. This being the case, it was 

 as cheap to protect by dusting as by spraying at Middlesex Fruit Farm. At 

 the other two orchards, with smaller trees and less time spent in going for 

 water, protection proved somewhat cheaper by spraying than by dusting, pro- 

 vided that our cheapest spray material is considered. 



In most orchards where dry lime-sulfur and spreader is to be used, it is 

 probable that the cost will not be far from that of dusting. 



Summary. 



The primary infection of the leaves was prevented equally well by lime-sulfur, 

 Bordeaux mixture, and dry-mix sulfur-lime. The primary infection of the 

 leaves was prevented more completely by spraying with lime-sulfur than by 

 dusting with sulfur. 



The prevention of pedicel infection by the fungicides improved the set of 

 fruit. 



On Mcintosh plots sprayed with lime-sulfur four times, there were 1.2 per 

 cent and 0.2 per cent scabby apples; while on their respective check plots there 

 were 69.4 per cent and 81.0 per cent scabby apples. 



The addition of calcium caseinate spreader to lime-sulfur-lead arsenate spray 

 did not result in increased protection against scab. 



A fifth application of lime-sulfur did not increase the protection against 

 scab afforded by four applications. The necessity for a late application for 

 scab control is probably affected less by the rainfall of August than by the 

 degree of scabbiness attained by the tree in June and July. 



Dry-mix sulfur-lime did not control scab on Mcintosh as completely as did 

 lime-sulfur. 



The substitution of Bordeaux mixture for lime-sidfur for the preblossom 



