152 CROP PRODUCTION 



fungus and to cut and burn these promptly. Spraying 

 with fungicides will also prove helpful. 



Other Fungous Diseases 



The Brown Rot of stone fruits is another serious 

 menace to plum culture. It is the disease that so often 

 causes the rotting of the fruit upon the tree before picking 

 or in the baskets after picking. It is caused by a fungus 

 which produces myriads of spores from the affected 

 fruits, these spores being carried by the wind and starting 

 new centers of disease when they light upon other plums. 



Many of the injured fruits hang as shriveled mummies 

 upon the tree through the winter and spring while others 

 remain upon the ground beneath the tree. These de- 

 velop new Crops of spores in spring and summer, these 

 spores often causing the disease to appear upon the 

 blossoms in spring and the new crop of fruit in summer. 

 Consequently the destruction of all these mummied 

 plums is desirable if we hope to check the disease. Then 

 by spraying with the self-boiled lime-sulphur wash 

 serious injury may be prevented. 



Young plums are sometimes affected by a curious 

 disease which causes them to become strangely swollen 

 with hollow spaces where the pits should be. The 

 disease is called Plum Pockets: it is due to a parasitic 

 fungus closely related to the one that causes Peach Leaf- 

 curl. The swollen plums often become covered with 

 a powder made up of the spores of the fungus. Then 

 the diseased plums fall off, but threads of the fungus 

 remain in the twigs and grow along with the twigs so 

 that succeeding crops on such branches are very likely 

 to be diseased. Consequently it is desirable to cut off 



