232 
Journal of Agricultural Research 
Vol, VIII, No. 6 
a fungus belonging to the genus Helicosporium has been isolated from 
leaves collected at Kenilworth, D. C., Arlington, N. J., and New York 
and Brooklyn, N. Y. The parasitism of this fungus has been demon¬ 
strated by successful inoculations made during three years with six 
different isolations of the fungus on nine species of pond lily (Nymphaea 
spp.). Hitherto, so far as ascertained, no data upon this disease have 
been published, and the causal fungus is described as a new species under 
the name Helicosporium nymphaearum. 
The fungus gains entrance to the host most readily through the stomata, 
which occur only on the upper leaf surface. Sections of infected leaves 
show the mycelium ramifying through the intercellular spaces and 
occasionally between cells which have become separated. Many of the 
cells of the epidermis and parenchyma become filled with discolored 
coagulation products and the nuclei and chlorophyll bodies disintegrate. 
In the older spots the tissues are seen to have more or less completely 
collapsed and fungus hyphae are found ramifying both between and 
within the decaying cells together with bacteria and various protozoa, 
a condition to be expected in a decaying mass of tissue floating on a 
watery medium. The sclerotia and multiseptate conidia are developed 
sparingly on the diseased leaves and rather abundantly on many of the 
common culture media. 
Spraying experiments with ordinary Bordeaux mixture and with soda- 
Bordeaux mixture were carried out during one season. The disease 
had gained a considerable start before the work was undertaken; 
hence, the control of the disease was not as complete as it might other¬ 
wise have been. However, as shown by careful comparisons of sprayed 
and unsprayed plots, the leaves sprayed with Bordeaux mixture were 
clearly 50 per cent less injured by the disease than were the unsprayed 
leaves. The control by the soda-Bordeaux mixture was almost as high, 
but in this case a slight spray injury of the leaves was observed. During 
the following two seasons this treatment was continued by the owner 
on a commercial scale with satisfactorv results. 
