DRUPACEOUS FRUITS 123 



the flower stalk. Infection of the twigs may also occur 

 directly from diseased fruit. 



From repeated observations it seems probable that the 

 branches cannot be infected through their unbroken skin, 

 or if so, only rarely. Smith ^ states that the examina- 

 tion of hundreds of twigs in all stages of disease showed 

 that every one was associated with blighted and persistent 

 flowers. 



The inroads of this disease are so serious that many 

 peach and plum growers have been obliged either to secure 

 a remedy for this pest or abandon the crop. Years in 

 which there is full fruitage, accompanied by damp, warm 

 weather, are almost certain to bring a severe attack. But 

 it is not the weather which directly causes the rot; rather 

 it is the fungus which causes the rot when the weather 

 gives the proper conditions for the development of the 

 fungus. 



The mmnmified fruit that falls to the ground serves as 

 the hibernating quarters of the causal fungus. If these 

 mummies be carefully observed in the spring, some of 

 them will be seen to bear small stalked disks (Fig. 55). 

 These are the organs which furnish spores for the following 

 spring. 



It follows that any practice which destroys or covers up 

 these mummified fruits lessens the spring infection. Active 

 treatment in the form of spraying is also necessary. The 

 most successful spray is that employed by Scott,^ which 

 gave the following results: — 



' Smith, E.F., Jour. MycoL, 7, .37, September, 1891. 

 - Scott, W. M., U.S. Dept. Agr. Bur. Plant Indus. Circ. 27, April, 

 1909. 



