DISEASES INJURIOUS TO FRUITS. 131 



Remedy. The remedy for this is Bordeaux mixture applied 

 just before the flowers open in the spring and two to four ap- 

 plications of it later at intervals of about two weeks. 



Black Rot (Sphaeropsis malorum).^his disease often 

 causes serious rotting of the quince just before maturity. It 

 generally starts from the calyx end. The remedy is a preven- 

 tive, and consists of spraying with Bordeaux mixture. 



Diseases of the Plum. 



Plum Pocket (Exoascus pruni). This is a name given ;b 

 certain peculiar deformities which occasionally take the place 

 of plums on the trees. They consist merely of a thin shell vith 

 no evidence whatever of seed. They appear in early summer, 

 and some seasons this disease is very abundant and then for 

 a number of years it may scarcely appear at all. It is due to 

 the presence of a parasitic fungus which attacks the young 



fruit, and by growing with- 

 in it causes the peculiar de- 

 velopment which finally re- 

 sults in the formation of the 

 so-called pocket. This, or a 

 similar fungus, may also at- 

 tack the foliage and cause 

 irregular swellings and dis 

 tortion. 



Remedies. It will some- 

 times be found that a sin- 

 gle tree will be troubled 

 with this fungus for a se- 

 ries of years and it will not 

 spread much. When this is 

 the case such trees should 

 be destroyed, as they are 

 likely to be centers of in- 

 fection, and the diseased fruit should be picked and destroyed. 

 Some varieties are more subject to its attack than others. 



The leaf curl of peaches is caused bya fungus similar to 

 that which causes plum pockets and recent experiments show 

 that this disease may be kept in check by spraying with thick 

 Bordeaux mixture or a solution of sulfate of copper just be- 



Fig. 47. Leaf curl of plums in- 

 volving twig and foliage. 



