84 The Ohio Naturalist. [Vol. VII, No. 4, 



tin 89 O. Agric. Exp. Station, published b_v the writer in 1S97, 

 and is as follows: 



"The histor}^ of this trouble is not an extended one, yet its 

 restatement ma}^ help in later considerations. The fungus was 

 first described in 1868, by Berkely and Curtis,*^ from specimens 

 on a wild plant from Cuba. It was at the time called Perono- 

 spora Cuhensis. In 1S8S the same fungus was found upon cu- 

 cumbers in Japan'. 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.* 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 Cucurbitaceoe, annd 

 attack the seedling plants." It was afterwards found by him 

 upon cucumbers, squashes and pumpkins in various parts of the 

 State.'' The same year it was reported by Professor Gallow^ay^" 

 from Anona, Fla., and College Station, Texas. Humphrey" 

 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^- 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 Jersey in 1892 and in 1893. About this time 

 it began to be destructive to field cucumbers in south-eastern 

 New York^-"*, 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", 

 but did not prove serious. 



In 189(i, 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 189(i." 



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, 1.52-1.53. 



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. E.xp't Station, 1891, p. 248. See also Report Cunn. Exp't 

 Station 1891, p. 97. 



13. Stewart loc. cit., p. 1.55. 



14. Bulletin 73, pp. 231-4. 



