Family Liliaceae 291 



improper storage conditions, and by early topping 

 in the field where a green neck offers a favorable 

 entrance of the rot. The latter is of a dry nature, 

 and the affected bulbs become blackened and 

 wrinkled at the neck (fig. 52 d). Selby 1 recommends 

 treating the bulbs with formaldehyde gas as recom- 

 mended for the white potato, p. 336. 



Pink Root 



Cause Unknown fungus. 2 



Pink root is a serious disease which is threatening 

 the onion industry in the Laredo districts of Texas. 

 The disease apparently is not new, but it has not 

 been investigated before. The work of the writer is 

 as yet incomplete, hence no complete statement can 

 be made at this time relative to the disease. 



The roots of affected sets first turn slightly yellow- 

 ish, when they are known as "Yellow root, " and then 

 pink. Affected roots dry up, and the bulbs con- 

 stantly make an attempt to produce new rootlets, 

 which even under favorable conditions become pink 

 and die. At the end of the season and because of the 

 attempt of the bulb to produce new roots, a nipple is 

 usually formed at the bottom of the center plate of 

 the bulb (fig. 54 1 and k). The disease is carried with 

 the young sets from the seed beds to the field. It 



1 Selby, A. D., Ohio Agr. Expt. Sta. Bui. 214 : 414, 1910. 

 3 Investigations by the author seem to show that pink root is 

 caused by a pathogenic fungus. 



