64 STATE HORTICULTURAL SOCIETY. 



LEAF SPOT CONTROL ON CHERRIES AND PLUMS. 



A du.sting experiment on i)lums was carried through the season at 

 Hart on the farm of our president, ]\Ir. George Hawlej'. Work was 

 done in three separate orchards which included five varieties, namely, 

 Monarch, Grand Duke, Arch Duke, Bradshaw and Lombard. Three 

 applications of dust were made and ^Ir. Hawley sprayed the other 

 parts of each orchard with lime-sulphur. A check plot was left for 

 each variety. The season however, was so dry until late in the summer 

 that only a very little leaf spot developed even on the checks. The 

 only exception to this was with the jMonarch and Arch Duke. The 

 foliage of Monarch seems to react very quickly to any unfavorable con- 

 dition. About August 1st the foliage of the check trees of this variety 

 were quite yellow but the trouble apparently was not due to leaf spot. 

 On adjacent dusted and sprayed trees, the foliage was in excellent condi- 

 tion. The contrast was shown more distinctly on the last check tree 

 which received some dust. One-half the tree was yellow and the other 

 half green. Later, leaf spot developed on the check but all the trees 

 lost their foliage sooner than other varieties, probably because of their 

 being so susceptible to any unfavorable condition such as dry weather. 

 The Arch Duke check trees showed some leaf spot by September 1st 

 but it could not be called serious. The dusted and sprayed trees were 

 in equally good condition. This work, also, will have to be continued 

 before any definite statement can be made. 



Experiments for the control of leaf-spot on cherries were continued 

 this year at Traverse City on the Titus Brothers farm and the work was 

 done by Mr. Johnston. Two varieties, English Morello and Mont- 

 morency, were included in the work and the blocks of each were divided 

 into five plots as follows: 



1. Check 



2. Lime-sulphur, 13^2 in 50 



3. Bordeaux 4-7-50 



4. Copper sulphate dust (20% dehydrated copper sulphate) 



5. Sulphur dust (80-10-10) 



Arsenate of lead was used whenever desirable. Five applications 

 were made on the Morellos as here indicated: 



1. Just before blossoms opened 



2. Just before blossoms had dropped 



3. Two weeks after the second 



4. July 7 



5. August 16, about two weeks after harvest. 



The Montmorencies were not given the first and last api)lications. 

 All dusting was done when weather conditions were ideal. The season 

 as a whole was unfavorable to leaf spot development and on the Mont- 

 morency trees there was never enough leaf spot to give anj' conclusive 

 results. Only very little developed on the Morello checks until early in 

 August but from then until Septeml^er 1st it came on rapidly so that the 

 check trees were defoliated before the middle of September. There was 

 no leaf spot on any of the treated trees but the foliage on both dusted 

 l)lots was in better condition than where sprayed and the foliage in the 

 Bordeaux plot was better than where sprayed with lime sulphur. The 

 Bordeaux, however, had a very undesirable effect upon the fruit. The 

 cherries were stunted and smaller tiian on other trees. This, of course, 



