356 Minnesota Plant Diseases. 



latter are largely store-house diseases. Experiments in formalin 

 treatment and with other chemicals have been unsuccessful. Good 

 ventilation of the stored fruit and a frequent sorting- to remove 

 the rotted fruits, thereby diminishing the chances for infection 

 from the spores which are formed on these fruits, are also recom- 

 mended. Any damage, such as bruising or cracking the fruit 

 skin, is to be avoided in all processes of handling the fruit. (See 

 Fig. I.) 



Bitter rot or ripe rot of apples [Glomerella rufoma-culans 

 (Berk.) Sp. von Schr.]. This is also known simply as apple rot. 

 It attacks apples before they are ripe, and also apples in storage ; 



■- -s- '^ 



., _;2!^ V^ ^^ H ■' 





Fig. 189. — Blue mold soft rot of apple. Accessory spores of the futtgus. Highly mag- 

 nified. After L. F. Kinney. 



it is a very destructive parasite. The parasite is one of the burnt- 

 wood fungi, and it is the summer-spore stage that is the most 

 conspicuous and the form which causes most damage. Where 

 the fungus attacks the frviit, a small brownish red spot appears 

 and increases in size until a considerable area of the apple is in- 

 volved. The spot becomes somewhat sunken, is soft, and the 

 apple underneath has a bitter taste. On the surface of the spot 

 arise usually in well-defined circles the summer-spore masses 



