CLOVER SCLEROTINIA 155 



Sclerotinia megalospora, Wor., on Vaccinium uliginosum. 



Woronin, Mem. Acad. Imp. St. Petersburg^ ser. vn. } vol. 

 xxxvi., 1888, 10 pi. 



CLOVER SCLEROTINIA 



(Sclerotinia trifoliorum, Eriksson.) 



During certain seasons this fungus is very destructive to 

 the different kinds of cultivated clover (Trifoliwti). It 

 also attacks Sainfoin (Onobrychis sativa), Lucerne (Medi- 

 cago sativa\ Fenu-grec (Trigonella foenum-graecum\ and 

 Medicago lupulina. 



The leaves are first attacked, and if the weather is suf- 

 ficiently moist a delicate white mycelium appears on the 

 surface, and extends to adjacent plants ; finally the leaves 

 shrivel and decay. Numerous minute, blackish sclerotia 

 are formed during winter on the dead leaves and roots 

 remaining in the ground. During the summer these 

 sclerotia produce one or two ascophores of the usual 

 Sclerotinia type, brown in colour, quite smooth, stem long 

 and slender, hymenium or disc concave or saucer-shaped, 

 thus differing from S. sclerotiorum. The spores of the 

 ascophore form directly inoculate the leaves. Conidial 

 condition unknown. 



PREVENTIVE MEANS. This disease has only been 

 recorded as present in Britain quite recently, and may 

 fortunately still be considered as rare. Where clover fields 

 are attacked, it is necessary to abstain from cultivating this 

 crop for several years. I have noticed this disease in a 

 plot of Trifolium incarnatum once near Sheire, Surrey. 

 Wherever the disease appears it should be promptly dealt 



