Family Liliaceae 289 



Control. A very effective treatment is to sow the 

 seed in a seed bed and later transplant the sets. 

 This method not only insures a crop free from smut, 

 but the quality and the yield are benefited. An- 

 other method which generally gives good results is 

 to apply to the soil at sowing time from 500 to 700 

 gallons per acre of a solution made up of one pint of 

 formaldehyde in thirty gallons of water. This is 

 applied with a drip attachment of the seed drill. 

 For this method to be effective the soil must be in 

 good condition of tilth. 



Rust 



Caused by Puccinia allii D. C. 



Rust is a rare disease with onions in the United 

 States, and very little is known about it. It is 

 doubtful if it will ever cause damage serious enough 

 to warrant treatment. 



Anthracnose 



Caused by Vermicularia circinans Berk. 



This disease seems to be confined to the bulbs 

 only. It is characterized by black spots (fig. 54 h) 

 which are made up of various rings one within the 

 other. Each ring consists of minute black dots, 

 which are the acervuli of the fungus and which pos- 

 sess numerous black hairs or bristles (fig. 54 i, j). 

 19 



