250 STATE BOARD OF HORTICULTURE. 



bad wound of the surface is apt to be followed by the develop- 

 ment of the disease in the tissue just beneath, with the general 

 characteristics specified above as occurring in Navels. 



In the packing-house or in transit the point of attack may 

 be the navel end, but it is more commonly where two fruits are 

 pressed together. Usually only one of the fruits so touching is 

 affected at first, though after it becomes thoroughly rotted the 

 disease usually communicates to the other. If the conditions 

 are favorable to the growth of the fungus, it may spread from 

 a single affected fruit to all those adjacent, and in time to the 

 whole box. 



This disease, being entirely a matter of the fruit and belong- 

 ing particularly to ripe fruit, evidently always gains its entrance 

 to the fruit from the outside and never from the tree. The 

 conditions necessary to accomplish this are: 



First — That the spore of the fungus should rest uinjii or neav 

 the surface of the fruit. It may be carried there lij^ the wind, 

 or by touching decayed fruit upon which the spores are being 

 produced. 



Second — Sufficient water upon the surface of the fruit to 

 cause the germination of the fungus. 



Third — The right condition of temperature. The fungus will 

 grow in such a range of temperatures, however, that this con- 

 dition may be considered to be practically always present. 



The germination of the spores of the fungus is thus seen to 

 be much the same as the germination of the seed of a higher 

 plant. 



The reason that the navel end is particularly liable to the 

 attack of the rot fungus is that in case a drop of moisture finds 

 its way within this structure, it is less liable to rapid evapora- 

 tion, and so favors the germination of any spores that may also 

 find their way there. The same explanation accounts for the 

 common abundance of this fungus in fruit with broken skin. 

 The point at which moisture will accumulate and remain 

 longest when fruit is sweating after packing, or while it is 

 stored in the packing- or curing-house, is the point where the 

 fruit touches an adjacent fruit; and at this point, therefore, 

 the germination of the fungus most commonly occurs. 



If sufficient refrigeration is maintained, the fruit will be 

 entirely safe from the attack of the fungus; but the cold tem- 

 perature is likely to condense a large amount of water upon 



