282 MANUAL OF FRUIT DISEASES 



considerable influence on the disease. In the Pacific North- 

 west, for example, little or no curl exists east of the Cascade 

 Mountains, where the annual rainfall is light; on the other 

 hand, west of these mountains the rainfall is heavy and curl 

 is very destructive. In these two regions the temperature 

 is approximately the same. 



Control. 



The time and thoroughness of the application of remedial 

 measures are important points in the control of peach leaf- 

 curl. It is imperative that such work be done before the buds 

 swell in the spring. Conjectures with reference to the winter 

 and spring activities of the pathogene lead one to infer that 

 spraying should prevent the disease. It has been shown that 

 the application of almost any common fungicide ordinarily 

 controls the trouble satisfactorily. One spraying is sufficient and 

 may be made in the fall, or in the spring before the buds swell. 

 Never spray more than once, as it is a waste of time and materi- 

 als : and do not spray for curl after the leaves are expanded, for 

 such an operation is useless and dangerous. Spray thoroughly, 

 making sure to coat every bud. If the season is favorable to 

 curl, the unsprayed buds will show the disease. Ordinarily 

 lime-sulfur solution of standard Baume test, 32, at a strength 

 of 1 to 15 or 1 to 20, is effective. If San Jos scale must be 

 combated, both troubles may be controlled by using the fun- 

 gicide at scale strength, 1 to 8. Scale can be controlled as 

 effectively by spraying in the fall as in the spring. Bordeaux 

 mixture of any strength, or copper sulfate 2 pounds to 50 

 gallons of water, are also effective in controlling peach leaf- 

 curl, and may be used when scale is not a factor to be considered. 



REFERENCES 



Reddick, D., and Toan, L. A. Fall spraying for peach leaf cuil. 



Cornell Univ. Agr. Exp. Sta. Circ. 31 : 65-73. 1915. 

 Pierce, N. B. Peach leaf curl, its nature and treatment. U. S. Agr. 



Dept. Veg. Phys. and Path. Div. Bui. 20 : 1-204. 1900. 



