THE AMERICAN GOOSEBERRY-MILDEW IN EUROPE. 100 



reach him. It appears to me that here the disease is gradually spreading. 

 It seems scarcely credible that this disease, which is so striking, could — if 

 it had existed in this country — have been hitherto, completely overlooked ; 

 yet, on the other hand, the example of the Pseudoperonospora of Rostow- 

 zew on Cucumis proves that such cases may occur. Consequently it is 

 difficult to hold a definite opinion on the subject." 



Prof. A. de Jaczewsky, Inspector of Vegetable Pathology to the 

 Russian Minister of Agriculture, has sent me the following information : 

 " With regard to S. mors-uvce, I am now able to give you some more 

 details about the occurrence of this parasite in Russia. During the 

 summer of 1902 I observed it personally at Simbirsk, and I received 

 specimens from the following localities : Kaluga, Poltava, and Lomza, 

 in Poland. In considering the question of the origin of the present 

 outbreak, it seems clear to me that the fungus has been imported, and 

 consequently that my previous opinion that the fungus was endemic to 

 Russia is wrong. In all the localities above named, which are very widely 

 separated, the disease has appeared only within the last two or three 

 years, and has never been observed before. It began in the gardens 

 where gooseberry-bushes (new varieties or new bushes) had been obtained 

 from nurserymen at Riga, Kaluga, Tambov, &c, who import various 

 plants from America, and amongst them gooseberry-bushes. The facts 

 seem to me to prove the American origin of the fungus, and also to 

 account satisfactorily for the sudden appearance of the disease in 

 localities so widely separated. As regards the identity of S. mors-uvce 

 with S. tomentosa, I may say that I agree with you (see Bibliogr. 4, p. 72) 

 that morplwlogically both these fungi are identical. It may be that we 

 have to do with two biological races of the same species, each with a 

 well-defined area, and I do not suppose that the fungus could now pass 

 from Euphorbia* to Ribes. S. tomentosa has been known in Russia 

 since 1870, and in Switzerland I have observed it very frequently in 

 many different localities ; but neither in Russia (until the present 

 outbreak) nor in Switzerland has Ribes been attacked. Also, S. mors- 

 uvce has now appeared in Russia in localities where Euphorbia does not 

 occur." 



Since the above was written, an article has appeared by Prof. Rostrup 

 (see Bibliogr. 5) in the July number of the Danish journal " Haven," t 

 recording the appearance of the American Gooseberry-mildew in Denmark. 

 Prof. Rostrup received, at the beginning of last June, branches of Goose- 

 berry bushes bearing berries attacked by S. mors-uvce, from two localities 



Tik^b-Egnen in Nordsjaelland, and Stavnholt, on the north side of 



Furesp. Information was obtained that in both localities the Goose- 

 berry bushes which first showed signs of the disease had been obtained, 

 three years ago, from the same nursery. Prof. Rostrup personally 

 inspected, on June 17, the garden at Tik^b in which the outbreak has 

 occurred, and has described in detail the devastation caused by the 

 disease. All the English varieties of Gooseberries which had beer 



* S. tomentosa occurs on Euphorbia dulcis, E. heUoscopia, E. palustris, E. 

 Peplus, E. platyphyllos, E. stricta, E. virgata, and E. Cyparissias, var. palustris. 



f I am indebted to Mr. L. A. Boodle, F.L.S., for kindly giving me a translation i I 

 this article. 



