26 EXPERIMENT STATION BULLETIN. 



EXPERIMENTS WITH CHERRIES AND PLUMS 



The work with cherries and plums has consisted of comparisons of 

 the dusting and spraying methods of application and testing calcium 

 and magnesium arsenates in comparison with lead arsenate. 



EXPERIMENTS IN 1918 

 CALCIUM ARSENATE ON CHERRIES AND PLUMS 



Blocks of Moore's Arctic plum and Early Richmond cherry on the 

 Horticultural grounds at East Lansing were used for making a com- 

 parison of calcium arsenate with lead arsenate._ The effect on the foli- 

 age was the main point of consideration. 



Materials. The materials were used as follows: 



1st. Calcium arsenate (dry), 1 Ib. in 50 gal. No lime. 

 2nd. Lead arsenate (dry), 1% Ib. in 50 gal. 



They were used in combination with lime-sulphur solution, diluted 

 at the rate of 1 to 40. All spraying was done with a spray gun and with 

 high pressure. Each material was used on a plot of from seven to nine 

 trees of each kind of fruit. Check plots of equal size of each kind of 

 fruit were left unsprayed. 



Applications. Three applications were made on the plums and two 

 on the cherries. The first one was not made on the cherries. They were 

 as follows: 



1st. Just before blossoms opened. 

 2nd. Soon after the petals had fallen. 

 3rd. About two weeks after second. 



RESULTS 



The foliage of all trees was in excellent condition throughout the sea- 

 son. There was no injury that could be traced to spraying material. 



A 



DUSTING JAPANESE PLUMS 



A planting of mixed varieties of plums on the College grounds at East 

 Lansing was dusted in 1918. There were several species and several 

 varieties of each species, including European, Japanese and native 

 species. Since Japanese varieties are very subject to injury by several 

 spraying materials, they were dusted to determine if such treatment 

 would have any ill effects on the foliage. No check plot was left un- 

 treated nor was any other material used. 



Material. A 90-10 mixture of sulphur and lead arsenate and pure 

 sulphur were used. 



