138 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE MEANS EMPLOYED TO COMBAT THE AMERICAN 

 GOOSEBERRY-MILDEW IN SWEDEN. 



By Jakob Ebtkbson, Ph.D., Professor at the Royal Academy of 

 Agriculture, Experiment Station.. Stockholm. 



On account of the discovery of the American gooseberry- mildew in 

 Sweden in the summer of 190-5. I sent on July 31 of that year the 

 following report to the Minister of Agriculture in Sweden : — 



u For more than half a century a serious disease appearing on cultivated 

 gooseberries, viz. the American gooseberry-mildew, Spharotheca mors-iiva 

 (Schwein.). Berk., has caused great destruction over a very large area in the 

 North- American continent. This disease has determined the course adopted 

 in the culture of the American gooseberry, and has made it impossible in 

 America to cultivate the best varieties of European gooseberries, since 

 they have proved to be more susceptible to the attacks of the mildew than 

 the American species. As a consequence of this the American fruit- 

 growers have been driven to the necessity of raising varieties from wild 

 species of Bibes native in America (i?. oxyacanthoides andi?. Cynosbati) ; 

 these varieties, while certainly of considerable value, have never reached 

 the same perfection as the best European gooseberries, all of which are 

 varieties of Bibes Grossularia. 



u Will the European culture of the gooseberry be able to maintain in 

 the future the high position which it has hitherto occupied*? We have 

 good reason to ask this question, now that it is known that the American 

 gooseberry-mildew has at length appeared in Europe. The first appear- 

 ance of the disease in Europe was reported in the year 1900 from the North 

 of Ireland, where it was noticed at that time in three gardens. Since that 

 date, each year that has passed has seen the establishment of the mildew 

 in fresh localities. Up to the beginning of the present year, the disease 

 had been reported from eleven localities in Ireland. In 1901 the fungus 

 made its appearance in Russia, viz. in the government of Moscow ; the 

 very next year it appeared in six fresh localities in the Russian Empire. 

 Now the disease is reported from widely separated places in Russia. 

 From facts which have lately been discovered, it appears that in 1900 and 

 1901 the gooseberTy-mildew may have immigrated also into Denmark and 

 Sweden. At the end of last year it was known that the disease had 

 appeared in seven localities in Denmark, and this year the fungus was 

 found to be present at one place in Blekinge in Sweden (where it was 

 first noticed in 1901), and at one locality in West Norway. 



The almost simultaneous appearance of the disease in widely separated 

 localities in different European countries, as well as the rapid spread of 

 the disease wherever it has become naturalised, remind one naturally of 

 the earlier immigration of the potato-fungus (Phytophthora tnfestans, 

 De By.), and the vine-mildew [Oidtum Tuekeri, Berk.), in the middle of 

 the forties. These species of fungi, since their appearance, have never 



