150 DISEASES OF ECONOMIC PLANTS 



Other plants upon which the same disease occurs are: 

 Azalea {Rhododendron viscosum Torr.); sheep laurel, or 

 lambkill {Kalmia angustifolia L.) ; sweet pepper bush, 

 or white alder (Clethro. aim folia L.) ; leather leaf (Cas- 

 sandra calyculata Don.); huckleberry (Gaylussacia resi- 

 nosa T. & G.) ; the teaberry, or wintergreen {Gaultheria 

 procumhens L.). 



Burning of the infected areas is recommended. 



Fly speck (Leptothyrium Pomi (Mont. & Fr.) Sacc). — 

 Fly speck is identical in character with that described for 

 the apple. 



CURRANT 



Knot (Pleonedria Berolinensis Sacc). — This disease was 

 described by Durand ^ in 1897 as prevalent in some regions 

 of New York State. It has since been found in several 

 other states and may be expected wherever currants are 

 grown. 



The first symptom is wilting of the foliage, which soon 

 turns yellow, dries up, and falls away. The diseased clus- 

 ters of fruit are smaller than normal color prematurely, 

 and fall with the foliage, leaving only the bare stalks, which 

 soon die. Cuttings made from the apparently healthy 

 bushes in a diseased field usually grow slowly, which 

 seems to indicate that the fungus causing the disease 

 is present in even those stalks which appear healthy. 

 After the death of a stalk small, wartlike, sporiferous tuber- 

 cles appear in great number upon its surface. 



Cuttings should not be taken from diseased fields. 



> Durand, E. J., N.Y. (Cornell) Agr. Exp. Sta. Bui. 125, February 

 1897. 



