432 STATE BOARD OF AGRICULTURE. 



leaves for spore discharge studies were secured, was used for a spraying 

 experiment planned to get more definite information as to the value of the 

 pre-pink application on scab control. The trees in this orchard were about 

 seventeen years old. 



Schedules of applications made. Two plots of about fifty trees each were 

 sprayed according to the schedules here given: 



Plot I. Sprayed according to ''regular" schedule. 



1st. When buds had separated in the clusters. 



2nd. When petals had fallen. 



3rd. Two weeks after the second application. 

 Plot II. Sprayed according to "pre-pink" schedule. 



1st. When buds were in the "pre-pink" stage. 



2nd. When buds had separated in the clusters. 



3rd. When petals had fallen. 



4th, Two weeks after the previous application. 

 Plot III. Check. No treatment. 



Both sprayed plots were treated in exactly the same manner except that 

 one received the "pre-pink'" application and the other did not. Lime- 

 sulphur solution, lK-50,* was used on both plots for all apphcations. Lead 

 arsenate powder was also used for all applications except the "pre-pink". 



The various applications were made on the dates here listed: 



"Pre-pink" application Aprils 



Pink or cluster application April 26 



Calyx application May 12 



Two weeks application May 27 and 30 



Referring back to the spore discharge studies we find that no spores were 

 discharged for some time after the "pre-pink" application and the conclusion 

 might be made that this application was put on too early as the first spores 

 were not discharged until April 21. This is explained by the fact that from 

 April 8 to 20 the temperature was so low that the blossom buds did not 

 advance. The warmer weather which followed forced the buds out quickly 

 and apparently at the same time hastened the discharge of scab spores. The 

 relation of temperature to spore discharge is probably very close but there 

 is little information available concerning this. There was rainfall on April 

 21 and 22. The twenty-third was very warm and there was a hard rain 

 again on April 25. The buds had separated in the cluster on the twenty- 

 fifth but the cluster application could not be made until the twenty-sixth 

 because of the rain. The buds were in condition for the cluster application 

 for three days beginning with the twenty-fifth. 



RESULTS. 



Adverse weather conditions greatly reduced the crop but there was enough 

 fruit produced to get definite results. An epidemic of blossom blight did 

 much damage but there would still have been a fair crop had there not been 

 a severe frost on May 16. The results of the counts made of Duchess are 

 given in table 1. 



•In this and future discussions, the strength of the lime-sulphur solution is indicated in this manner; 

 "1 Ji-50" means that IJi gallons of lime-sulphur solution has been diluted with water to make a total 

 of 50 gallons of solution. 



