New York Agricultural Experiment Station. 355 



plant in Cuba; and has since been found on the cucumber 

 {Cucumis sativus), the muskmelon {Cucumis melo), the watermelon 

 {Citrulhis vulgaris), the squash (Cucurbita mawima), the pumpkin 

 {Cucurbita j)epo) and the gherkin gourd {Cucumis anguria). It is 

 likely that when the fungus becomes better known it will be 

 found on still other cucurbitaceous plants. During an outbreak 

 of the disease in New Jersey in 1891, Dr. Halsted* sought for it 

 on the star cucumber [Sicyos angidatus) and the wild cucumber 

 [Echinocijstis lobata) but failed to find it. 



On both field-grown and hot-house cucumbers it is exceedingly 

 destructive. The muskmelon, too, suffers severely from its at- 

 tacks. Muskmelon plants attacked by the disease lose their 

 leaves in much the same manner as do cucumber plants, except 

 that the yellow discoloration is less marked in the muskmelon 

 and the dead spots are dark colored. The diseased plants may 

 continue to produce melons but they are of a very inferior quality. 

 The watermelon is affected in the same way. Dr. Halsted attrib- 

 utesf the partial failure of the New Jersey watermelon crop in 

 1891 to this fungus. On the squash and pumpkin the disease 

 presents the same general appearance as on the cucumber, but as 

 yet it has not done much harm to these plants. However, it 

 seems to be on the increase and it is not improbable that in the 

 near future Long Island squash grov»'ers will have to fight this 

 disease or abandon the crop just as cucumber growers are doing 



now. 



HISTORY OF THE DISEASE. 



The disease with which we are dealing has a comparatively 

 short history. It was originally discovered on a wild plant in 

 Cuba and the fungus causing it was first described! in 1869 by 

 Berkeley and Curtis, who gave it the name Peronospora cubensis. 

 For the next twenty years nothing was heard of it and then in 

 1889 it suddenly appeared in Japan and in New Jersey. The first 

 announcement of its occurrence in this country is to be found on 

 page 152 of the Botanical Gazette for June, 1889. Dr. Halsted, 



♦Halsted, B. D. Notes upon Peronosporeae for 1S91. Ann. Rept. New Jersey Agri- 

 cultural Experiment Station for 1891, p. 248. 

 tLoc. cit. 

 t Journal Linnaean Society, Botany, Vol. 10, p. 363. 



