476 STATE BOARD OP AGRICULTURE. 



Such a condition is recognized as being ideal for the development of the type 

 of injury found. The foliage of the trees in the lime-sulphur plot showed no 

 injury but was usually not so bright in appearance as in the other plots. The 

 foliage of trees in both dusted plots was in excellent physical condition. 



In 1921 there was no foliage injury and, in physical condition of foliage, 

 the dusted plots ranked first, the bordeaux plot second, and the lime-sulphur 

 plot a little below the bordeaux plot. 



An unusual effect of bordeaux upon the fruit of the English Morello devel- 

 oped in 1921 . The fruit in this plot was much smaller in size than on any other 

 plot, A report of the same or a similar trouble has recently come from the 

 Northwest.* The trouble there was evidently caused by the use of strongly 

 alkaline spraying materials and was probably due to the same cause here. 

 So little is known about the trouble at the present time that no definite state- 

 ment can be made regarding it. 



Control of Brown Rot and Slugs. There was some brown-rot on the Mont- 

 morency check in 1920, but it was completely controlled on all dusted and 

 sprayed plots. There was also considerable injury by slugs in 1920 to the 

 foliage of the check trees of both varieties, but none of this injury was found 

 on dusted or sprayed trees of either variety. 



♦ EXl'ERIMENTS WITH PLUMS. 



Summary of previous experiments. The only earlier work on plums which 

 will be mentioned includes two experiments, one on Japanese and native 

 plums in 1918 and another on Japanese plums in 1919. The foliage of such 

 varieties is very susceptible to injury by most of the ordinary spraying ma- 

 terials and one object of these experiments was to determine if sulphur dust 

 would injure the foliage and the results indicated very plainly that it could 

 be used with safety on Japanese and native varieties of plums. 



EXPERIMENTS IX 1920 AND 1921. 



Experiment at South Haven. At South Haven in 1920 on the H. E. 

 Hawley farm, a comparative test of lime-sulphur, sulphur dust and copper 

 sulphate dust was made. The variety was Lombard. It was a general test 

 for the control of leaf-spot, curculio and brown rot but only leaf-spot will be 

 considered here. The results were not conclusive as the foliage of the check 

 trees showed no leaf-spot at any time during the summer and the foliage of 

 the trees in all plots was in excellent physical condition at all times but the 

 foliage of dusted trees was shghtly better than that of the sprayed trees. 



Experiment at Hart. At Hart in 1921 on the Geo. A. Hawley farm, a com- 

 parison was made of dusting and spraying for the control of leaf-spot, brown 

 rot and curculio on plums. This work was done in three separate orchards 

 and included five varieties, viz.. Monarch, Grand Duke, Arch Duke, Lombard 

 and Bradshaw. The materials used were sulphur dust and lime-sulphur. 



A detailed description and report of the experiment will not be given as the 

 results were not conclusive because of the absence or small amount of injury 

 by any of the troubles mentioned. Late applications of sulphur dust were 

 made on other plots for the control of any brown rot which might develop 

 after harvest and a detailed report of that work will be found in another part 

 of this bulletin. 



*D. F. Fisher, Effect of Alkaline Sprays on Sweet Cherries, Journal of American Society for Horti- 

 cultural Science, Oct. 1921. 



