Family Cruciferae 215 



The disease attacks the leaves (fig. 36 a-b), causing 

 small circular gray or straw-colored spots. The 

 acervuli and the salmon-pink spore clusters appear 

 only under moist conditions. The causative ftmgus 

 differs from CoUetotrichum brassicce Sch. and Sacc. 

 The acervuli are small, scattered on both surfaces 

 of the spots. The conidiophores are short (fig. 36 c), 

 conidia hyaline cylindrical one celled (fig. 36 d), setae 

 dark brown to black, slender, i to 3 septate (fig. 36 c). 

 On the stems the spots are more elongated. On 

 the leaves the spots are said to be much smaller 

 than those produced by Cylindrosporium brassiccB 

 F. and R. (fig. 36 e). Anthracnose is not carried 

 with the seed. No method of control is as yet 

 known. 



Phoma Rot 



Caused by Phoma napobrassiccB Rost. 



Phoma rot is a disease which is common in the 

 north of England. It is also foimd in New Zealand 

 and in Canada. In the United States it has been 

 reported but once, by Clinton' of Connecticut. 



Phoma rot seems to be a storage trouble, although 

 the disease is first introduced from the field. 



Symptoms. In the field, the disease is first noticed 

 at digging as a rot around the crown, the top of the 

 plant readily pulling off. In storage the disease is 



'Clinton, G. P., Connecticut Agr. Expt. Sta..,z(>^.Ann.Rept. : 

 355-358, 1912. 



