452 PLANT DISEASES 



rapidity when once established. Uredo- and teleuto- 

 spores are frequently to be found growing together in 

 small pustules forming irregular patches on both surfaces 

 of the leaves. The pustules or heaps of spores are at 

 first covered by the white epidermis of the leaf, which 

 eventually ruptures, exposing the dark-brown masses of 

 spores. Unlike the Pink rust {Puccinia arenariae, Wint.), 

 the Uroinyces is not a native of Britain, and has probably 

 been introduced along with carnations, and in like manner 

 is transferred from one place to another in this country; 

 hence it is important to examine carefully all newly- 

 received carnations. 



Preventive Means. — The same as those recommended 

 under Pink rust, p. 253. 



AMERICAN GOOSEBERRY MILDEW 



{Sphaerotheca mors-uvae, Berk, and Curt.) 



This gooseberry disease, described at p. 97, has quite 

 recently appeared in a very destructive form in Ireland, 

 where it appears to be extending its area. 



STRAWBERRY MILDEW 



■ (^Sphaerotheca castagnei, Ldv.) 



This destructive parasite, well known as 'hop mildew,' 

 under which name it is described at p. 95, has recently 

 completely overrun strawberry gardens in different parts 

 of the country. The foliage is attacked first, but the 

 delicate white bloom is not so evident on the leaves as 

 when it passes on to the fruit, which when ripe is often 



