APPLE GROWING IN CALIFORNIA. 



93 



Spraying with some good fungicide must not be neglected. An early 

 spring application of lime-sulphur at the dormant strength, or of 

 Bordeaux mixture, applied as the buds are swelling, should be made. 

 This should be followed by later applications, which may be combined 

 with the arsenical sprays for codling moth, being careful that com- 

 patible mixtures are used. Either Bordeaux mixture or lime-sulphur 

 with neutral arsenate of lead, according to Geo. P. Gray of the State 

 University of California, may be safely used, or Bordeaux with either 

 the acid or neutral arsenate of lead. Zinc arsenite should not be used 

 with either Bordeaux or lime-sulphur. 



FIG. 49. Rhode Island Greening affected with apple scab. (Original) 



CROWN GALL. 



(Bacterium tumefaciens. ) 



This is a very common disease of the apple, often found on nursery 

 trees, and sometimes becoming so abundant that great numbers of them 

 have to be destroyed. Trees with this disease, if planted in the orchard, 

 may live for years, but are usually stunted and never develop into the 

 best type of trees. 



The cause of this affection is known to be a bacterium, which often 

 enters through a wound, thus starting the disease, which manifests itself 

 in swellings or galls. These occur on the crowns of trees, as well as the 

 roots, at some distance from the crowns, and are very rarely seen above 

 the ground. 



There is no cure for crown gall, but preventive measures, such as 

 inspection and destruction of all affected nursery trees, may keep it out 

 of the orchard. 



