270 PLANT DISEASES 



CELERY LEAF SPOT 



{Fhyllosdcta apii, Hals.) 



Dr. Halsted discovered this disease on celery in the 

 United States. It differs from Cercospora apii in the spots 

 on the leaf being dull brown, never pale coloured. 



It is described and figured in the N. Jersey Agric. Expt. 

 Station Report, 1891, p. 253. 



Septoria petroselini, Desm., Var. Apii, B. and C. — Causes 

 celery leaves to become brown and studded with small 

 black dots over the entire surface. 



CARROT DISEASE 



(Phoma sanguinoknta, Rostr.) 



Forming greyish-brown, sunken, cankerlike spots on the 

 root ; the mycelium during subsequent growth extends into 

 the stem, where depressed areas are formed which prevent 

 the umbel from being fully developed, hence no seed is 

 produced. Numerous minute, dark-coloured perithecia 

 are present on the diseased patches, the conidia escaping 

 in long, flesh-red or blood-red strings or tendrils ; a char- 

 acter by which this fungus can be readily distinguished. 



Preventive Means. — It is useless planting diseased 

 roots with the object of procuring seed, as the bloom 

 is always destroyed. Great care should be exercised in 

 storing not to include diseased carrots, otherwise the pest 

 spreads by contact. 



