The Springdale news., 1909-09-03
BITTER ROT OF THE APPLE.
Paper Read Before Horticultural
 Society by C. S. Bouton.

such magnitude as the bitter rot of the apple. especially in paper the reading of which will occupy not over twenty minutes, it is doubt less as essential to know what not to say as to know what to say Therefore while it might be in teresting to tell something Of the history of this disease, the losses it has occasioned. and the many ex- periments made in studying it., it will be best to confine our at tention to facts relating to the disease and it's characteristics. it's modes of dissemination, and to methods of treatment for its con trol and eventual eradication
 The disease owes it's name to the taste of the affected tissue It is easily recognized upon the ap- pie by the black circular spots with clearly defined margins, which soon become sunken as the disease pro gresses It is due to a specific fun gus, more lately known as @Gion- cerella rufomaculous. This is another way of stating that it is not due to any inherent disease or condition in the tree in the air or in the soil. It comes from tI.e particular fungus and from nothing else
 This fungus grows on developing apples, and on many other fruits like pears, peaches, quinces, grapes. and even tomatoes, but ordinarily is particularly destructive to only the apple As far as known. ft does not form limb cankers upon any other kind of trees.
 All fungus diseases are propa- gated by spores For the propa- gation of it's kind where it's spores may Lot reach. fungus plants form a mycelium. Of which the spawn of mushrooms is an example This mycelium vegetates in the tissues Of it's host, and when conditions become favorable produce Sp0re
 
 rot of the apple, the favorable con ditions consist Of humidity and - temperature of more than S3 de- grees F.. but after Spore produe- tion has begun. the combination of heat and humidity is not necessary This is important to note in de termining the time for first spray ing WhenZthis combination. .ex ists as early as forty days after the falling of the petals spraying with standard Bordeaux mixture should at once begin Otherwise the treatment may be delayed for as much as ten days longer.
 Modes of Dissemination.
 have said that the mXeeliHm yegetates in the tissues of it's host In the apple, it is either in the fruit. or in the wood. The bitter rot fungus does not attack the leaves It cannot attack heal thy bark without assistance. It needs a wound. or an exposed surface A wound caused by shoes. or ladder, a broken limb, or even by the severing of the ap- pie from it's fruit spur will give opportunity for lodgment. So also will a decayed surface adjoining healthy tissue Let the spores of the fungus find Judgment in any such place under the favorable com bination of moisture and temper ature above noted, and it be- gins active growth upon the cell ular tissues and in the end forms black, smoky-looking, depressed cankers It is these cankers and in the apples which the disease has attacked and left hanging on the tree in the form of shriveled mum ies' that the disease survives the winter Now. suppose crop of apples is growing on tree upon which one or more of these num- mics is hanging. or upon which the bitter rot canker is active, June comes and brings the favorable com
 
 bination previously mentioned. the spore-p producing functions become active, spores are produced in abund- ance in the mummies or the cahKers or both. then 1t only remains tor some agent to scatter them abroad The most active agent is raln, but heavy dews. wind and insects, especially pomaee flies, which reed upon deeayed fruit. aid in the work of dissemination. The spore mos ses when first produced are eov- cred with mucilaginous coating which enables them to adhere To the surface of any apple upon which they may fall. In dry weather these surfaces lose this sticky quality and hence the dl-