596 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



ON THE INCREASE IN EUROPE OF THE AMERICAN 

 GOOSEBERRY-MILDEW (Sphcerotheca mors-uvce (Schwein.), Berk. & 



Curt.). 



By Ernest S. Salmon, F.L.S., F.R.H.S. 



When giving an account, at p. 139 of vol. xxv. of this Journal, of the 

 occurrence in 1900 of the American Gooseberry-mildew in a garden at 

 Ballymena, Ireland — the first appearance in Europe of the disease — the 

 opinion was expressed that in all probability the disease would invade 

 other parts of Europe. In 1901 (see p. 778 of vol. xxvi. of this Journal) 

 the disease recurred with increased severity in the original locality in 

 Ireland, but was not reported from elsewhere. In the present year, 1902, 

 not only has the disease occurred in several fresh localities in Ireland; 

 but it has been reported from two widely-separated districts in Russia, 

 where it caused wholesale destruction to the Gooseberry crop. 



First, as to the spread of the disease in Ireland. Mr. Nixon has sent 

 me the following notes on the occurrence of the disease during the pre- 

 sent year in the original station at Ballymena : — " I had the Gooseberry 

 bushes sprayed once this year, but now (June 11) I find the fungus is 

 abundant both on the berries and on the young wood. I notice that the 

 disease is far worse — that is, it spreads far more quickly — in damp or 

 rainy weather. We have had a great deal of rain here this last April 

 and May, and the temperature during May was lower at night than 1 

 have ever known it in all my experience of gardening. We are seriously 

 thinking of burning all our trees — over three hundred — this season. We 

 are greatly sheltered by very tall treei on the south side. I should think 

 most of them are eighty feet high. I never saw many, if any, gardens so 

 shaded on the south side. Possibly this may have something to do with 

 the disease spreading so quickly, but its origin is as yet entirely a mystery 

 to me." In August Mr. Nixon wrote : — " I have destroyed a great many 

 trees by fire just on the plot where they grew. We have a Large Green 

 Rough or Hairy variety of Gooseberry which seems to resist the disease." 

 At the same time Mr. Nixon informed me that the disease had appeared 

 in a garden at Knocktarna, Coleraine, Londonderry. On writing to the 

 owner of the garden I received the following information on this fresh 

 outbreak of the disease : — " The mildew, which appeared for the first time 

 in our bushes this year, was first observed about the middle of July, when 

 the berries were ripening. I feel confident that there was no occurrence 

 of the disease last year. It began upon a plantation of young bushes 

 bought four years ago from Portadown. It spread rapidly, until the fruit 

 upon every bush was attacked in two gardens, quite separate from each 

 other ; yet our neighbour's gardens, only on the other side of the road, 

 were quite free from it. None of the Gooseberry bushes appeared to 

 remain unattacked by the disease. This is a heavy clay soil, and in 

 former years was famous for Gooseberries. I have heard of the disease 

 appearing in a garden at Aghadowey, but only a few bushes were attacked 



