Fig. 54. Onion Diseases. 



a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, 



c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to 



d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- 

 tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through 

 acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. 

 to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. 

 pirJc root of onion showing nipple formation, tn. a formaldehyde drip attachment 

 to a planet junior seed sower, n. a copper tank drip with flexible black tin tube and 

 valve (m. and n. after Stone). 



