56 



FUXGI AND FUNGICIDES 



excellent popular account of the disease, by Dr. Hal- 

 sted, appears in Bulletin 78 of the New Jersey Experi- 

 ment Station. There are many other short accounts 

 scattered through our horticultural literature. 



The Brown Rot 



Monilia fructigena 



The brown rot of stone fruits is probably familiar to 

 every grower of plums, peaches or cherries in the older 

 portions of the United 

 States. It is one of the 

 most destructive fungous 

 diseases of fruits, attack- 

 ing not only the fruit 

 itself, but also the twigs, 

 leaves and blossoms. It 

 is occasionally found upon 

 the apple and pear, but in 

 the Northern States is 

 seldom destructive to fig. 29. brown rot. aiAONiriED. 



these fruits, althoUS'h in «'<^i»ai"s of spores; 6, branching mycelium. 



some southern localities it is reported to do serious dam- 

 age. The annual cycle of the fungus of brown rot may 

 be brieflv outlined as follows, starting with its attack 

 upon the fruit : A minute spore (Fig. 26) falls upon a 

 green plum on which there is a little water, left by rain* 

 or dew, and sends out a germinating tube which pene- 

 trates the skin of the fruit. Once inside it grows rap- 

 idly, pushing its branches through the pulp in all direc- 

 tions, and thus forming a dense mass of mycelium, 

 which absorbs the contents of the cells, disorganizing 

 the tissues and causing the so-called rot. The affected 

 plum at first turns brown in one or two spots ; these 

 gradually enlarge until, finally, the whole plum becomes 

 brown and ^^ rotten." When it has reached this stage it 



a 

 FIG. 29. 



