PYTHIUM UE BAKYANUM HESSE 



BY 



E. J. BUTLER, m.b., F.r.s. 

 Imperial Mycologist, 



Pytliiiim, de Baryanum Hesse, though extremely common as a 

 facultative parasite in garden soils in Europe and the United 

 States, has not. so far as the writer is aware, previously been re- 

 corded in Asia. It has recently been isolated from the soil of the 

 Pusa Farm and a short note on its occurrence may be not without 

 interest. 



The species was first described by Hesse 1 in 1874, as the cause 

 of a disease, since widely known under the name of " damping off," 

 of seedlings of Camelina sativa. It has frequently been observed 

 since on many hosts, and a brief summary of our knowledge of its 

 habits and the plants which it is capable of attacking was published 

 in these Memoirs in 1907 2 . More recently it has come into pro- 

 minence in Central Europe as a cause of the disease of beet-root 

 (especially sugar beet) known as ' ' wurzelbrand 3 . ' ' 



In November 1912, some seeds of castor (Ricinus communis) 

 which had been sown in pots of unsterilised Pusa soil and had 

 failed to germinate, were examined. A Phycomycete, bearing 

 numerous oospores, was found in the caruncle of the seed. Iso- 

 lated on boiled ants in the manner described in the writer's memoir 

 on Pythium, a copious clean growth was obtained in water. This 



1 Hesse, R. Ueber Pythium de Baryanum, ein endophytischer Schmarotzer, Halle 

 (Inaugr. Dissert.), 1874. 



2 Butler, E. J. An account of the genus Pythium and some Chytridiacece. Mem. Dept. 

 of Agric. in India, Bot. Ser., I, No. 5, 1907. 



3 Peters, L. Ueber die Erreger des Wurzelbrand es, in Busse W. Untersuchungen iiber die 

 Krankheiten der Ruben, 5, Arb. Kaiserl. Biol. Anstalt fiir Land-und Forstwirtschaft, VIII, 2, 

 1911, p. 211. (Gives a full account of the association of Pythium de Baryanum with this dis- 

 ease, including references to previous work.) 



