I5 8 FUNGOUS DISEASES OF PLANTS 



mixtures first came into use in the treatment of downy mildew 

 of the grape. The experiments of Millardet in France in 1881, 

 and subsequently, led promptly to the perfection of Bordeaux 

 mixture as a fungicide. 



XIII. DOWNY MILDEW OF THE CUCUMBER 

 Plasmopara cubensis (B. & C.) Humphrey 



CLINTON, G. P. Downy Mildew, or Blight, Peronoplasmopara cubensis (B. & C.) 



Clint., of Musk Melons and Cucumbers. Conn. (New Haven) Agl. Exp. 



Sta. Kept.: 329-362. pis. 29-31. 1904. 



FARLOW, W. G. Notes on Fungi i. Bot. Gaz. 14: 187-190. 1889. 

 HUMPHREY, J. E. The Cucumber Mildew. Plasmopara Cubensis (B. & C.) 



Mass. Agl. Exp. Sta. Rept. t 8: 210-212. 1890. 

 SIRRINE, F. A., and STEWART, F. C. Spraying Cucumbers in the Season of 



1898. N. Y. Agl. Exp. Sta. Built. 156: 3?6-39 6 - pis. 1-4- 1898. 

 STEWART, F. C. The Downy Mildew of the Cucumber : What it is and how 



to prevent it. N. Y. Agl. Exp. Sta. Built. 119 : 154-183. pis. 1-4. 1897. 



Habitat relations. The two most important diseases of the 

 cucumber, or indeed of the commonly cultivated members of 

 the gourd family in this country, are the downy mildew and the 

 bacterial wilt disease. It has been definitely ascertained that the 

 Plasmopara is the chief cause of the poor crops which have 

 prevailed in the cucumber districts of New York and a part 

 of New Jersey in recent years. The downy mildew of the 

 cucumber has an interesting though brief economic history. In 

 1869 the fungus was described upon a wild plant found in Cuba. 

 It appears that this fungus was not again reported until early in 

 the spring of 1889, when it was found in greenhouses in New 

 Jersey, 1 and by the end of the season it had been detected upon 

 the cucumber, squash, and pumpkin in the field in several loca- 

 tions in that state. It was further reported during the same season 

 from several southern states. Subsequently it developed 2 that the 

 fungus had been found in Japan early in the same year. 



This disease-producing organism is now known to occur in 

 many sections of the eastern and southern United States, but 

 no mention of its occurrence in Europe has as yet come to 

 my attention. It is most abundant in regions which have long 



1 Halsted, B. D. Peronospora on Cucumbers. Bot. Gaz. 14 : 149-150. 1889. 



2 Farlow. Notes on Fungi, I.e. 



