256 Peach-Growing 



relationship exists between its development and certain 

 weather conditions. If rainy or hot and muggy, especially 

 for a week or two before the ripening of a variety, nearly 

 the entire crop may become infected and lost. 



Course of development of hrowrirrot. 



"The disease appears on the fruit as a small circular 

 brown spot, which under moist, warm conditions enlarges 

 rapidly, soon involving the entire fruit in decay. The 

 spots do not usually become sunken, and the fruit remains 

 plump until almost entirely decayed. The fungus growing 

 in the tissues of the fruit breaks through the skin, forming 

 small, grayish tufts of spore-bearing threads. These tufts, 

 although few on young spots, soon become so numerous 

 as to give the diseased area a grayish, moldy appearance, 

 which is responsible for the term peach * mold ' sometimes 

 applied to the disease. The spores which are produced 

 in great abundance by these fungous tufts are blown by the 

 wind and carried by insects and birds from fruit to fruit, 

 tree to tree, and orchard to orchard. Finding lodgment 

 on the fruit under favorable conditions of temperature and 

 moisture, these spores germinate, producing a fungous 

 gro\\i:h which ramifies and kills the tissues. These dead 

 tissues turn brown, and the fungus breaks through the 

 surface, producing another crop of spores. The process 

 is very rapid, only a few days intervening between one 

 generation of spores and another." ^ 



Methods of control. 



The development of the self-boiled lime-sulfur mixture 

 by W. M. Scott ^ in 1907 made a new epoch not only in 

 » Farmers' Bull. 440. 2 Bur. of Plant Ind. Circ. 1. 



