1 88 FUNGOUS DISEASES OF PLANTS 



Extent of losses. The years when the greatest injury has been 

 reported from various sections of this country are as follows : In 

 1887 Dr. Erwin F. Smith reported it from Maryland and Delaware. 

 The extent of the injury probably resulted in a shortage of the 

 total crop estimated at 800,000 baskets of peaches. It was also 

 very abundant in 1891 and 1893. Again, during subsequent years, 

 it has been of considerable importance in the Delaware and Chesa- 

 peake peninsula. In 1897 an almost total loss of the crop in 

 Alabama was reported, the following year being somewhat less 

 disastrous. Quaintance states that the year 1900 was the worst in 

 the history of commercial peach and plum growing in Georgia. 

 He estimated the loss at 40 per cent of the total crop. This 

 would mean a loss of between $500,000 and $700,000 for that 

 state alone. 



Symptoms. The name brown rot has long been applied to this 

 disease, and it is the one in most common use, although many 

 others, particularly ripe rot, are also employed in some sections. 

 This disease affects practically all stone fruits (Prunus spp.), very 

 few varieties of either peach, apricot, nectarine, plum, or cherry 

 being free from it during seasons favorable to the fungus. The 

 fruits are the most common seat of injury, but other vegetative parts 

 are likewise susceptible. As a rule the fruits are apparently most 

 easily attacked after they have become half grown, and the sus- 

 ceptibility increases from this time to ripening. Fruits in clusters, 

 under which conditions moisture would be held, are more readily 

 injured. 



The disease first makes itself evident as a small, dark brown, 

 decayed spot. This spot increases in extent until the whole fruit 

 is infested, but there is at first no diminution in size, and no sunken 

 area develops. Before the whole fruit has become decayed, how- 

 ever, evidences of a superficial development of the conidia of the 

 fungus may appear. As a rule, however, the fungus develops its 

 spores only after the fruit has decayed considerably. The fungus 

 then breaks through the surface in the form of small tufts, con- 

 sisting of masses of conidiophores with an abundant production 

 of conidia, the appearance being as shown in Fig. 69. 



The flowers may also succumb, and that is more commonly 

 the case the year after an unusual outbreak of the disease, due 



