86 FUNGOID PESTS OF CULTIVATED PLANTS. 



BEAN BUST. 

 Uromyces Fabce (Pers.), PL. VII. fig. 106. 



This extremely common parasite is found on the foliage, stems, and 

 leaves of the Garden Bean (Vicia Faba), as well as the Horse Bean or 

 Field Bean, covering them with a rust-coloured powder, which consists of 

 the scattered uredo and teleutospores. 



The uredospores are first produced, and are the most profuse, bursting 

 through little rounded pustules which elevate the cuticle. They are 

 globose or nearly globose in form, of a yellowish-brown colour, and a 

 roughened or shortly spiny surface (20-30 x 17-20 /^). 



These are ultimately succeeded by the teleutospores, which are of a 

 darker colour, somewhat club-shaped, with the outer coat much thickened 

 at the apex, and terminated by a depressed pore. They are longer and 

 rather broader than the uredospores, and apparently smooth, with a 

 colourless deciduous pedicel (24-27 x 17-30 /*). 



This species is known in France, Belgium, the Netherlands, Germany, 

 Switzerland, Austria, Hungary, Bohemia, Italy, Finland, Siberia, South 

 Africa, and North and South America. 



It is difficult to suggest a remedy when none have proved really 

 successful. How often the bean haulms covered with rust and teleuto- 

 spores are left in heaps to rot, when it would be much more politic to 

 burn them instead of leaving them to disseminate the disease ! 



Sacc. Syll. vii. 1921 ; Mass. PL Dis. p. 229 ; Cooke, M. P. 201 ; Cooke, 

 Hdbk. No. 1512 ; Plowr. Brit. Ured. 119. 



FRENCH BEAN BUST. 



Uromyces Phaseoli (Pers.), PL VII. fig. 107. 

 Uromyces appendicidatus, DC. 



Changes of names in the Uredines have been so numerous of late years 

 that it would seem a relief to fall back on such an old name as Uromyces 

 appendiculatus again if not forbidden. 



This rust is found on the leaves of most kinds of garden beans ; what- 

 ever name the cluster-cups may have had, we find the uredospores to be 

 plentiful enough in rounded pustules, of a pale cinnamon-brown. They 

 are either round or shortly ellipsoid (24-33 x 16-20 /<), with a rough 

 surface. 



The teleutospores occur in darker, almost black, pustules to the eye, 

 which are soon ruptured, and the powdery spores set free. These teleuto- 

 spores are either subglobose or elliptical, with the spore- coat much 

 thickened about the apex, surmounted by an obtuse hyaline wart or 

 papilla. Externally the spores are smooth (26-35 x 20-26 /i). 



It is recorded in France, Belgium, the Netherlands, Germany, Switzer- 

 land, Austria, Hungary, Italy, Portugal, and North America. 



Spraying with potassium sulphide solution should be commenced as 

 early as possible after the manifestation of the disease, to be of any 

 service. There is no hope with the uredines when firmly established, 

 and the mycelium permeates the host-plant. 



