8 4 
The Ohio Naturalist. 
LVol. VII, No. 4, 
tin 89 O. Agric. Exp. Station, published by the writer in IS97, 
and is as follows: 
“The history of this trouble is not an extended one, yet its 
restatement may help in later considerations. The fungus was 
first described in 1868, by Berkelv and Curtis, 6 from specimens 
on a wild plant from Cuba. It was at the time called Perono- 
spora Cubensis. In 1888 the same fungus was found upon cu¬ 
cumbers in Japan 7 . Meanwhile, before this fact had been pub¬ 
lished, that is in 1889. Dr. Halsted, of New Jersey, had found the 
fungus upon hot-bed cucumbers at New Brunswick. 8 He then 
expressed the fear that “Market gardeners may have in the cu¬ 
cumber mildew a serious enemy, especially should it spread to 
squashes, melons, and other members of the Cucurbitacece , annd 
attack the seedling plants.” It was afterwards found by him 
upon cucumbers, squashes and pumpkins in various parts of the 
State. 9 The same vear it was reported by Professor Galloway 10 
from Anona, Fla., and College Station, Texas. Humphrey * 11 
reported it from Massachusetts, for 1890, upon garden cucumbers 
and squashes. He changed the name to Plasmopara Cubensis 
(B. & C.) Humph., since it was found to belong to that genus. 
In 1891 it was again reported by Dr. Halsted 12 who found it 
almost Everywhere about New Brunswick, though it had not 
been observed in 1890. Watermelons were attacked by it both 
there and at New Haven, Conn. The same disease was again 
prevalent in New Jersev in 1892 and in 1893. About this time 
it began to be destructive to field cucumbers in south-eastern 
New York 13 , where it continues to be prevalent and destructive 
to the present time. In 1895, the same trouble appeared in 
forcing houses in Ohio and in the writer.s garden at Wooster 14 , 
but did not prove serious. 
In 1896, it was very destructive in forcing houses at Hyde 
Park, and while not reported or studied, so far as known, in the 
pickle fields of Ohio and Kentucky, where the disease proved so 
injurious in 1897, there are some evidences, chiefly later infer¬ 
ences'from observations made at the time by growers, that the 
downy mildew prevailed to a more limited extent in 1896.” 
This subtropical species reproduces itself by short-lived 
conidia which germinate by swarm spores; no oospores are 
6. Journal Linnaean Society, Botany, x, 363. 
7. Farlow, W. G. Botanical Gazette xiv, 189. 
8. Botanical Gazette, xiv, 152-153. 
9. Journal Mycology, v. 201. 
10. Journal Mycology, v. 216. 
11. Eighth Annual Report Mass. State Ag’l Exp’t Station, 210-12. 
12. Report Botanist N. J. Exp’t Station, 1891, p. 248. See also Report Conn. Exp’t 
Station 1891, p. 97. 
13. Stewart loc. cit., p. 155. 
14. Bulletin 73, pp. 231-4. 
