Apr. IS, 1915 



Phoma Destructiva 



17 



showed growth in five days. Under ordinary laboratory conditions 

 stem cultures (tomato, cotton, and sweet clover) dry out in less than a 

 year and the fungus dies. Special medium was used in the hope of 

 obtaining a perithecial stage of the fungus, but no fruiting bodies other 

 than pycnidia have been observ^ed in culture or upon host tissue. 



TEMPERATURE RELATIONS 



The Phoma fungus grows well at ordinary room temperatures. Trans- 

 fers were made from a 2 -weeks-old corn-meal culture to string-bean agar, 

 potato cylinders, and corn-meal flasks and kept in incubators for a 

 period of ID days with the results given in Table V. 



Table V. — Temperature relations of the Phoma fungus 



Period of 

 growth. 



Average temperature (°C.). 



S.6 



IS.6 



10 days. .. . 



When re- 

 m ove d 

 to room 

 tempera- 

 ture. 



Growth 

 within 

 2 days. 



Growth 

 within 

 2 days. 



Growth I Growth 

 within I within 

 2 days. 2 days. 



Trace. 

 Contin- 

 ued 

 growth. 



Fair. 



Contin- 

 ued 



growth. 



Good. 

 Contin- 

 ued 

 growth. 



Good. 

 Contin- 

 ued 

 growth. 



Good. 

 Contin- 

 ued 

 growth. 



These tests show the minimum temperature of the Phoma fungus to 

 be about 6° C, the optimum temperature about 28°, and the maxi- 

 mum temperature between 32° and 33°. 



DISTRIBUTION OF THE DISEASE 



Information concerning the distribution of this Phoma disease of 

 tomato has thus far been obtained only through specimens sent in for 

 examination from Cutler, Fla., in 191 2; Punta Gorda, Fla.; Cuba; 

 Florence, S. C; Miamisville, N. Y.; and Herrington, Kans., in 1914. 



It seems probable that the disease is widely distributed but because 

 of the presence of associated fungi has often been looked upon as one of 

 the more commonly known fruit-spots. The seriousness of the disease 

 under favorable climatic conditions is suggested in the report of Mr. 

 James Brown, already mentioned, that this fruit-spotting had caused 

 heavy loss among the farmers of Dade County, Fla., in 191 2. 

 79827°— 15 2 



