298 FRUIT AND ITS CULTIVATION, 



Bladder Plum Disease (Exoascus pruni). This fungus 

 attacks the fruit of the Plum and Damson. The mycelium 

 enters the embryo of the flower, and when the fruit forms 

 it develops a bladder-like shape, hollow within, and stone- 

 less. As the mycelium of the fungus lives in the tissues 

 of the shoots, the only remedy is to cut off and burn those 

 that bear the bladder-like fruits. 



Gumming Disease (Coryneum beyerinckii). This dis- 

 ease attacks the Apricot, Cherry, Plum, and Peach. It 

 appears in the form of red patches on the under surface of 

 the leaves. In due course the disease develops, causes 

 the parts attacked to become dry, fall out, and leave cir- 

 cular holes in the leaves. It also attacks the shoots, and 

 causes a gummy substance to ooze out. Another fungus 

 (Cladosporium epiphyceum) also causes gum to ooze out 

 of the branches. Cut off and burn all shoots attacked. 



Silver-leaf Disease. The Plum, Peach, and Apricot 

 have of late years been attacked by a disease which causes 

 the leaves to assume a silvery hue. Some authorities con- 

 sider it to be caused by a fungus (Stereum purpureum), 

 but Mr. George Massee, F.L.S., the well-known myco- 

 logist, holds a contrary opinion. Anyway, whatever the 

 cause may be, trees attacked do not survive for more than 

 two or three years. Many remedies have been tried as 

 a cure or a preventive, but all have so far failed to act. 

 Clearly, the only course is to uproot and burn all diseased 

 trees. 



Currants and Gooseberries. 



American Gooseberry Mildew (Spaerotheca mors-uvae). 

 This is a very serious disease, which, had it not been for the 

 timely action of the Board of Agriculture in taking strin- 

 gent steps to stamp it out, might have annihilated the 

 Gooseberry in this country. It appears about May, in the 

 form of a delicate cobweb-like, white film, and later be- 

 comes mealy on the young leaf-buds, then on the shoots 

 and fruit. The fungus develops with alarming rapidity, 



