10 



ON THE FUNGUS FLORA OF GLASSHOUSE WATER 

 SUPPLIES IN RELATION TO PLANT DISEASE^ 



By W. F. BEWLEY 

 {Mycologist to the Experimental and Research Station, Cheshunt, Herts.) 



AND W. BUDDIN 



{Assistant Mycologist). 



(With 1 Text-figure.) 



It has long been recognised that the elimination of infection centres is 

 an important factor in the control of disease, but while the intimate 

 relation between polluted water and epidemics of human diseases is 

 now common knowledge, little attention has yet been given to the 

 corresponding relation between water contaminations and plant dis- 

 eases. Attention was drawn to this latter problem by a severe epidemic 

 of " damping-ofE " in tomato seedUngs in the early part of 1919 and pre- 

 liminary experiments showed that the causal organism, Phytophthora 

 cryptogea Pethybr. (5), was carried by the water used in cultivation. 

 Later in the year the same fact was proved in the case of a severe attack 

 of "buck-eye" rot of tomatoes caused by Phytophthora parasitica 

 Dastur(3). It was evident that a centre of infection existed in the water 

 supply and this appeared of sufficient importance to justify further 

 study. 



Sources of water. 



The water necessary for glasshouse cultivation is pumped from a 

 well or other source of supply into a galvanised iron or painted steel 

 tank placed at from 25 to 30 feet above ground. Here it is stored for a 

 varying period and thence conveyed direct to the house by means of 

 piping and hoses. In some nurseries covered tanks are used, but this is 

 by no means a constant practice. Uncovered tanks are open to contami- 

 nation by air-borne bacteria and fungus spores, as well as by debris 

 dropped by birds, which go there to drink. The sources from which the 

 water is drawn in the Lea Valley are the Water Company's supply, 



^ A grant in aid of publication has been received foi' this communication. 



