ADDENDA 445 



foliage prevents the spread of the disease. Spraying with 

 potassium sulphide solution answers the same end, and is 

 not so unsightly on the foliage. Diseased shoots and 

 fruit should be cut off in the autumn before the winter 

 fruit falls to the ground. 



Sphaerotheca pannosa, L^v. — Mycelium forming a white, 

 pruinose stratum on living leaves, fruit, and young shoots 

 of wild and cultivated species of Rosa. Diseased leaves 

 usually curl and fall after producing conidia only. On the 

 shoots and fruit the mycelium becomes felted and velvety, 

 and bears later in the season minute blackish perithecia 

 immersed in its substance ; perithecia subglobose, append- 

 ages hyaline, short, ascus solitary, subglobose, 8-spored ; 

 spores elliptical, 20-27 >^ 12-15 /*• 



AMERICAN COFFEE DISEASE 



{Stilbum flavidum, Cooke. 

 =^PistiUinaflavida, Speg.) 



This disease is almost as destructive to the coffee 

 industry in the New World as Hemileia vastatrix is in 

 the Old World. 



The symptoms of the disease are unmistakable ; circular 

 whitish blotches occur on the leaves, often in considerable 

 numbers, and are equally marked on both surfaces. Using 

 a pocket-lens, very minute fungi resembling a miniature 

 pin in shape, and of a clear yellow colour, can be seen 

 grouped on the spots on the upper surface of the leaf. The 

 berries are also sometimes attacked, being marked with 

 circular spots. On the young shoots the pale diseased 

 spots are elongated. 



