EXPERIMENT STATION BULLETINS. 



477 



Dry Lime Sulphurs and Similar Materials. 



EXPERIMENTS TO DETERMINE THEIR EFFICIENCY IN CONTROLLING APPLE SCAB 



AND PEACH LEAF-CURL. 



EXPERIMENTS FOR THE CONTROL OF APPLE SCAB. 



Comparative tests of dry lime-sulphurs and similar materials with lime- 

 sulphur solution have been made for several years and the results of all work 

 done previous to 1921 have been published.* A summary of that work is 

 included in this report. 



Experiment in 1921. A comparative test of dry lime-sulphurs with lime- 

 sulphur solution as summer sprays was made on Duchess apples at South 

 Haven in 1921. This work was done in the Harriman orchard. The trees 

 were about ten years old and had not been well sprayed in previous years. 



Materials and applications. Standard lime-sulphur solution and two 

 brands of dry lime-sulphur were used as follows : 



1. Lime-sulphur solution, 1^ gal. in 50. 



2. Dow dry lime-sulphur, 4 lbs. in 50. 



3. Sherwin-Williams dry lime-sulphur, 4 lbs. in 50. 



4. Sherwin-Williams dry lime-sulphur, 6 lbs. in 50. 



5. Check plot. No treatment. 



Lead arsenate was used with all materials. 

 Three applications were made as follows : 



1st. Pink application; when blossom buds had separated in the clusters. 

 2nd. Calyx application; just after the petals had dropped. 

 3rd. Two weeks after calyx application. 



Weather conditions. The season as a whole was quite dry, except very 

 early just as the blossom clusters were expanding. There was so much rain 

 during this period that it was impossible to make the "pre-pink" application. 



RESULTS. 



The fruit from all the trees in each plot was sorted at harvest into two 

 classes, "scabby" and "clean", and the results are given in table 21. 



TABLE 21. — RESULTS WITH DRY LIME-SULPHURS ON DUCHESS^ 1921. 



•Special Bulletin 102 and Quarterly Bulletin, November 1920. 



