PLANT DISEASES IN I908. 9 



The first year unlimed plots showed quite a marked falHng oft 

 in the amount of scab as a result of the extra year in grass. The 

 average for these plots was 6 per cent of scabby tubers as com- 

 pared with II per cent in 1907 and 13.6 per cent in 1908 on the 

 adjoining second year plots. 



For a discussion as to the methods of handling soil or seed to 

 prevent the introduction of scab and the treatment of land 

 already infested the reader is referred to the following publica- 

 tions of this Station : Bulletins 141 and 149 and the special cir- 

 cular entitled "How to Fight Potato Enemies." The former 

 bulletin is now out of print but the two latter publications will 

 be sent on request. 



Another matter was noted in connection with the yields on 

 the two portions of the field which is of practical importance to 

 the potato grower. There was a marked falling off in the yields 

 on the same land growing the second crop of potatoes in suc- 

 cession as compared with that growing the first crop of potatoes, 

 although 1200 pounds of high grade potato fertilizer had been 

 applied for each crop. The former gave slightly less than 83 per 

 cent of a full crop as compared with the latter, or 90 and 109 

 barrels per acre respectively. 



Seef-Boiled Lime-Sulpeiur as a Substitute for Bordeaux 

 Mixture for Apple Scab. 



Bordeaux mixture has been found to be the most effective 

 agent as a treatment for and as a preventative of the common leaf 

 and fruit diseases of the apple, but unfortunately it occasionally 

 causes injury to fruit an;l foliage. This matter of bordeaux 

 injury, or "spray injury" to apple trees as it is commonly called, 

 has been made the subject of quite exhaustive inquiry by Hed- 

 rick.* The reader is referred to his report on the subject for a 

 detailed discussion of the nature, causes and prevalence of spray 

 injury. With regard to the continued use of bordeaux mixture 

 on apple trees he summarizes his conclusions as follows : — 



"Bordeaux mixture is the best fungicide known to the apple 

 grower. Its use cannot be given up in fighting the apple scab. 



* Heclrick, U. P. Bordeaux Injury, Bulletin 287, N. Y. Agr. Exp. 

 Sta., 1907. 



