612 



THE MONTHLY BULLETIN. 



from as widely separated localities as Chula Vista, in San Diego County ; 

 Whittier, in Los Angeles County ; Santa Paula, in Ventura County, and 

 Lindsay, in Tulare County, and all these have, on being inoculated into 

 healthy trees, produced the same form of gummosis. Cultures of the 

 brown rot fungus have also been reisolated from the inner barK cor- 

 responding to the outer white line in Figure 349, and this has been done 

 from several other trees that had been inoculated. These reisolated cul- 

 tures have been placed again on lemon fruits and have given them brown 



Fig. 349. — Lemon tree inoculated with 

 pure culture of the Brown Rot fungus 

 iPythiacystis) November 23, 1912. Photo- 

 graphed May 6, 1913. The two narrow 

 black lines to the right are due to tar, not 

 gum, running down from a limb above. 

 ( Original. ) 



rot. Neat's-foot oil applied to the surface of lemon bark and lemon 

 fruits appeared neither to hinder nor to encourage the development and 

 infection of the Pythiacystis or brown rot fungus mycelium that had 

 been placed upon their surfaces. 



It is well known that the brown rot fungus lives in the soil, and that 

 wet weather and abundant rains encourage its growth. This would 

 seem to explain why flooding the trunk of the tree with water or allow- 

 ing the bud union to get below the soil would produce conditions favor- 

 able to infection of the lemon tree trunk, and bring on this type of 



