198 Diseases of Truck Crops 



conglutinans Woll. is given by Gilman. 1 Sporo- 

 dochia, lacking or greatly reduced, pionnotes never 

 present, conidia borne on short conidiophores strewn 

 throughout the mycelium. The majority of spores 

 are non-septate, a few are one to three septate 

 (fig. 31 e) ; conidia with higher septation are rare. 

 In old cultures, chlamydospores are produced in 

 great abundance (fig. 31 f). 



Control. Cabbage yellows cannot be readily 

 controlled. Naturally a clean seed bed should be 

 chosen (fig. 31 b-c). However, the healthy seedlings 

 when transplanted into infected fields will soon con- 

 tract the disease. The same also holds true even 

 when the seeds are disinfected. Neither is crop 

 rotation a sure method of control. It is doubtful if 

 fifteen years' rest from cabbage will free a soil from 

 the causative parasite. The best method of control 

 is the development of resistant varieties. This has 

 already been accomplished by Jones and Gilman 2 

 who selected a strain from the Hollander which 

 they named Wisconsin Hollander No. 8. This strain 

 is said to be nearly 100 per cent, resistant to wilt. The 

 same is also true for the Volga (fig. 32 a-b). The 

 question arises as to whether a cabbage selected for 

 resistance under Wisconsin soil will show it in a like 

 degree in other climatic conditions and soil. For 

 the cabbage the answer may be given in the affirma- 

 tive. For instance, the Houser and the Volga, which 



1 Oilman, J. C. f Annals Missouri Bot. Garden, 3 : 2-84, 1916. 



2 Jones, L. R., and Gilman, J. C., Wisconsin Agr. Expt. Sta. Bui., 

 38 : 1-69, 1915. 



