A New Apple Rot. 
9 
latter case, too, the skin of the fruit is often cracked in the affected 
areas apparently from loss of moisture. 
On the leaves of the pear the fungus produces brown spots of 
considerable size which are often situated along the margin or 
scattered over the surface in an irregular manner. (See Plate II 
and III). 
MICROSCOPIC characters. 
The rotting effects of this fungus are due to the invasion of 
the tissues of the plant by numerous branching threads or hyphse 
of mycelium. Thus a microscopic examination of the decayed part 
of an apple or pear reveals the presence of this mycelium in the form 
of an intricate network. These hyphse vary considerably in diame¬ 
ter in some cases being so slender as to be seen with difficulty under 
even a high power. In numerous instances, the mycelium may be 
found in the cell cavity, in which case the slender hyphse are often 
coiled to some extent. Within the affected tissues the mycelium is 
nearly hyaline, or but slightly yellowish in color and contains num¬ 
erous minute oil drops; but as the fruiting or spore-bearing portions 
of the mycelium are reached, the hyphse assume a brownish color. 
The conidiophores, or spore-bearing branches, possess rather thick¬ 
er walls than the feeding part of the mycelium and are freely septate 
near the terminus. 
The spores, conidia, are characteristic of those of the genus 
Alterncria. When seen in mass they appear blackish olive, but are 
of a brownish color when seen under the microscope. They differ 
much in size and shape, as well as in the number of cells composing 
them, varying from one cell in the smallest to ten or twelve cells in 
the largest. They are produced in simple or slightly branched chains 
with a narrowed portion, consisting of one or more lengthened cells, 
joining the spores. Thus, when the larger spores are separated they 
usually possess a somewhat flask-shaped form, the larger end rep¬ 
resenting the base or point nearest the conidiophore. 
Spores may often be found by examining the calyx end of 
affected specimens of fruit, but are obtained most readily by placing 
such fruit in a moist chamber for a few days. 
The spores germinate readily in water, each cell being capable 
of sending out a germ tube, and even portions of the conidiophores 
frequently act in the same manner. While the spores are capable 
of germinating as soon as mature, if conditions of moisture and 
temperature are not favorable they will remain dormant during the 
remainder of the season or until the conditions are suitable for 
growth. (Plate IV). 
TIME AND MANNER OE INEECTION. 
While the matter of infection has not been investi¬ 
gated to any great extent, it appears from observations made, in 
