EXPERIMENT STATION BULLETINS. 599 



SUMMARY. 



Phoma Root Rot is a disease of celery and celeriac known both in Europe 

 and America and is caused by the same fungus {Phoma apiiccla) in both 

 cases. 



The fungus also attacks parsley (Carum 'pelroselinum) , parsnip {Pasiinaca 

 sativa), carrot (Daucus carota), and caraway (Caruni carvi). 



The disease comes in on the croAvn of plants and causes dead leaves at 

 the base, ' 'stimting' ', and a pinching off near the surface of the soil. 



The causal organism requires a relatively low temperature (optimum 

 about 18°C.) and abundance of moisture and a large supply of oxygen for 

 best growth. 



The disease reaches its maximum of destructiveness in the spring and fall, 

 the hot weather of midsummer checks the advance of the fungus and gives 

 a crop free from its attack. 



Over- wintering is known to take place in the trash of the field. 



Control measures recommended are the use of disease-free plants and the 

 destruction of trash which harbors the pathogen, or when the disease is 

 severe, the rotation of crops. 



BIBLIOGRAPHY*. 



1. Bennett, C. W. Phoma root-rot of celery. Phytopath, 10:65. 1920. 



2. Coons, G. H. A Phoma disease of celery. Annual Report Mich. State 



Board Agr. 30:318. 1917. 



3. Coons, G. H. Michigan Plant Disease Survey for 1917, Celery. Report 



Mich. Acad. Sci. 20:444. 1918. 



4. Halsted, BjTon D. The celery leaf spot. Aimual Rept. N. J. Agr. 



Exp. Sta. 12:253-256. 1891. 



5. Klebahn, H. Krankheiten des Selleries. Zeitschr. fiir Pflanzenkrank- 



heiten 20:17-39. 1910. 



6. Quanjer, H. M. and N. Slagter. De Roest-of Schurftziekte van de 



Selderieknol en Enkele Opmerkingen over Andere Selderieziekten. 

 Tijdschr. over Plantenziekten 20:13-27. 1914. 



7. Van Hook, J. M. Celery root rot. Ohio Agr. Exp. Sta. Circ. 72. 1907. 



* This bibliography contains only those>eferences which bear directly on the disease in question 

 other references are given in the foot notes. 



