606 



THE MONTHLY BULLETIN. 



the bark, and another in which the killing of the inner bark lagged only 

 slightly behind that of the outer and in which the bark remained hard 

 as the areas of infection enlarged. As will be shown later, the former 

 is caused by the grey fungus {Botrytis vulgaris) and the other by the 

 brown rot fungus {Pythiacystis citrophthora), ])oth commonly known as 

 causing fruit rots in the citrus orchards and packing-houses of Cali- 

 fornia. 



Fig. 344. — Lemon tree inocu- 

 lated by inserting bit of grey fun- 

 gus (Botrytis) into the bark 

 Marcli 8, 1912. Pliotographed 

 July 13. 1912. (Original). 



Fig. 345. — Same tree as in Fig. 344. 

 Photographed May 10, 1913, nearly 

 11 months later, showing by chalk 

 lines the area of infected bark. A 

 large part of the gum had been 

 dissolved by spring rains. (Original. ) 



Grey Fungus (Botrytis) Gummosis. 



After the rains of March, 1912, attention was called to the grey fungus 

 (Botrytis) growing abundantly on the dead bark of gumming lemon 

 trunks at Santa Paula, especially where neat's-foot oil had been used. 



