712 



Journal of Agricultural Research 



Vol. XX, No. 9 



This experiment shows (i) that even under what may be considered 

 very good weather conditions for natural curing a considerable amount 

 of smudge will develop; (2) that exposure to moist weather for a week 

 after harvest practically doubled the amount of smudge; and (3) that 

 thorough artificial drying immediately after such exposure counteracts 

 the effect of excessive moisture. 



Experiment 3. — The sets used in this experiment were from a late 

 sowing and consequently were not harvested until September 14, 1918. 

 Smudge was prevalent on the extreme outer scales of a large percentage 

 of the bulbs at this time. Five bushels were placed in shallow crates 

 in the kiln drier, in which the temperature was maintained at ioo° to 

 120 F. One crate was removed at the end of one day, a second at the 

 end of two days, and the remaining three on the fifth day. Three 

 untreated crates used in the experiment were allowed to cure in a cov- 

 ered pile in the field with the remainder of the crop. On September 30 

 they were removed to a standard onion warehouse, where they were 

 stored during the winter with the artificially dried lots. On March 5, 

 1 91 9, when final notes were taken, a comparison of the artificially cured 

 and field-cured lots was secured by estimating the percentage showing 

 any signs of smudge after sets had been milled to remove the loose 

 scales. 1 The results are given in Table V. 



Table V. — Amount of smudge on artificially cured and field-cured onion sets at the end 



of the storage period 



Crate 

 No. 



9 



10 



Nature of treatment. 



Artificially dried. 



do 



do 



do 



do 



Field-cured 



do 



do 



Average of artificially dried crates. 

 Average of field-cured crates 



Length of 

 treat- 

 ment. 



Days. 

 I 



3 



5 



5 



5 

 16 

 16 

 16 



Percent- 

 age 



showing 

 any 



signs of 



smudge. 



33 

 31 

 72 



75 

 78 



75 



The foregoing experiments clearly establish the importance of moisture 

 as a factor in the advance of the disease during the curing and storage 

 periods. They also indicate that artificial curing immediately following 

 harvest greatly checks the progress of the disease as compared with 

 natural field-curing. 



1 It is the common practice to run "bottom" sets through a fanning mill as they are taken from storage 

 in order to remove the loose outer scales. 



