356 Fruit-growing in Arid Regions 



examined each year since, but no further evidence of curl 

 has been discovered. 



Some of the diseases can be controlled only by cutting 

 out the affected trees, as in peach-yellows. Pear-blight 

 could be controlled if all of the diseased limbs were re- 

 moved promptly, but this seems to be impossible for the 

 majority of orchardists. Brown-rot of the stone-fruits 

 has not as yet been successfully combated; and in wet 

 seasons it is very difficult and often impossible to control 

 such common diseases as apple-scab. This is due not 

 only to the inability to spray at the proper time, or the 

 material being washed off by the rains, though these are 

 important features. Unfortunately, the copper in bor- 

 deaux mixture is made soluble under some conditions, 

 and when this occurs, more damage results to fruit and 

 foliage from the corrosive action of the copper than from 

 the disease. 



The apples that come to our markets from the humid 

 states are more or less scabby and often discolored with 

 the sooty blotch, and the peaches are commonly dis- 

 figured by scab or some surface-growing mold. Our 

 growers have never been bothered by fungi that attacks 

 leaves and fruit, consequently they have been saved the 

 expense of spraying, and the fruit goes on the market 

 without a blemish. These are distinct advantages which 

 it is to be hoped will continue. 



We have a few diseases, however, and at least one of 

 them, pear-blight, is very destructive. These are de- 

 scribed in the following pages, and the latest information 

 in regard to their control is given. 



As in plant diseases, the insect enemies with which our 



