4 i8 



DISEASES OF CULTIVATED PLANTS 



rapidly if there is the least sign of sweating, hence tainted 

 onions should be thoroughly dried and used at once. 



Spots orbicular, perithecia concentrically arranged, seated 

 on radiating hyaline mycelium, very minute, furnished with 

 long, rigid, black hairs ; conidia oblong, hyaline, 10-14 X 3~4 /* 



Berkeley, Card. Chron., 1851, p. 595. 

 Stoneman, Bot. Gaz., 1898, p. 98. 



FIG. 130. Vermicularia circinans. i , onion 

 attacked by fungus ; 2, one of the black tufts 

 of the fungus ; 3, portion of a tuft showing 

 the conidia borne at the apex of slender 

 conidiophores, also the long black spines. 

 Figs. 2 and 3 highly mag. 



French potato scab. Dr. Ducomet has described a disease 

 of potatoes and tomatoes which when recurring on the tubers 

 would come under our conception of scab, but which he terms 

 'dartrose.' The fungus causing the injury is Vermicularia 

 varians (Ducomet). The disease, although present, is not 



