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CIRCULAR 76 5, U. S. DEPARTMENT OF AGRICULTURE 



Although ozone did not check infection of wounds, it retarded 

 enlargement of the lesions (fig. 6) . In table 6 unusually small lesions 



Figure 6. — Effect of ozone on blue mold decay on Rome Beauty apples inoculated 

 with Penieillium expansion and stored for 60 days at 31° F. : A, In atmosphere con- 

 taining 3.25 p. p. m. of ozone; B, in nonozonized atmosphere. 



on both the ozonized and the nonozonized fruit are recorded as re- 

 tarded. Obviously the small lesions on the nonozonized lots were due 

 to factors other than ozone. After 51 days' storage at 31° F. ozonized 

 York Imperial apples had 40.7 percent of the lesions retarded and 

 the nonozonized ones 9.1 percent. Thus ozone was responsible for 

 retarding growth in approximately 31.6 percent of the lesions. After 

 GO days at 31°, 80.3 percent of the lesions on ozonized Rome Beauty 

 apples were retarded and 31.3 percent on the nonozonized ones; or 

 49 percent of the lesions were retarded by the ozone. Retardation of 

 decay occurs only when ozone is present, however: after removal of 

 the fruit from the ozonized atmosphere, the decay lesions increase in 

 size as rapidly as do those on the nonozonized fruit. Although the 

 retardation is considerable, the affected fruit is still unacceptable and 

 so the retardation is not commercially important. 



Fruit Inoculated With Phialophora Malorum 



Sound apples of a uniform degree of maturity were selected for 

 inoculation with PMcdo'phora malorum. the fungus that causes the 

 so-called side rot of apples. Fruit free from wounds was selected 



