314 



DISEASES OF CULTIVATED PLANTS 



the pustules are pale orange, and irregularly scattered. Later 

 in the season small black clusters of teleutospores appear on 

 the under surface of the leaves. 



Aecidiospores orange, aculeolate, 20-28^ diam., paraphyses 

 clavate, orange. Uredospores orange, aculeate, 16-22 ju. 

 Teleutospores oblong, apiculate, warted, 5-10 septate, black 

 and opaque, 90-140 x 20-35 /*> pedicel thickened below. 



FIG. 93. Phragmidium rubi-idaei. i, pustules and teleuto- 

 spores on under surface of raspberry leaf ; 2, teleutospore ; 

 3, section through an aecidium ; a, chains of warted spores ; 

 b, paraphyses ; 4, uredospores. Fig. i nat. size, remainder 

 highly mag. 



Spraying with potassium sulphide arrests the spread of the 

 disease. If Bordeaux mixture is used it must be diluted, or 

 the foliage will be scorched. Diseased leaves that have fallen 

 should be swept up and burned. 



XENODOCHUS (SCHLECHT.) 



Teleutospores pedicellate, many-celled, cylindrical, brown, 

 forming large blackish spore-clusters. Aecidiospores in 



