272 Peach-Growing 



It has been observed that leaf-curl, which is sometimes 

 serious in California, as it is throughout the entire country, 

 appears to be largely controlled also by a November or 

 December application of bordeaux mixture. Where leaf- 

 curl is extremely bad, however, it is not so completely con- 

 trolled by a late fall application as by a spraying in Feb- 

 ruary or March. 



It seems probable that the lime-sulfur mixture used at 

 dormant-spray strength would be equally effective in 

 controlling these diseases and at the same time control San 

 Jose scale. 



As the peach twig-borer or peach-worm {Anarisa line- 

 atella) is also controlled (see page 233) by lime-sulfur applied 

 just as the buds are opening, the best spraying program 

 where these three troubles occur is to apply bordeaux mix- 

 ture during November or the first half of December for 

 blight and for a measurable control of leaf-curl; again 

 just as the buds are beginning to swell for the peach-worm 

 (or twig-borer) and the final control of leaf-curl and also 

 for the San Jose scale when that occurs. 



Crown-gall {Bacterium tumefaciens) 



This is a bacterial disease common to various tree-fruits, 

 also to raspberries, blackberries, and other plants. Prob- 

 ably the greatest economic importance of crown-gall on 

 peach trees is as a disease of nursery stock, since it is dur- 

 ing the nursery period that they are most likely to become 

 affected, and this stock probably constitutes the chief means 

 of dissemination. 



