Baldwin Fruit Spot
( Originally Published Early 1900's )
W. S. FIELDS, BUFFALO, N. Y.
The Baldwin Fruit Spot is a disease, so-called perhaps because it occurs on this variety more than on any other. But the specimens which I have in my hand are Northern Spies affected with this disease.
This fruit spot is called by various names and is confused with "Sooty Spot" and "Brown Spot," both of which are fungus diseases. The disease appears on the surface of the apple in the form of small brown spots, varying in diameter from one-sixteenth to one-eighth of an inch. The spots are slightly sunken or depressed, so that the surface has a pitted appearance. You will note that the spots are not uniformly distributed over the surface and are considerably more numerous towards the apical portion than towards the cavity of the fruit. In these specimens the cavity is practically free of the spots.
The spots extend into the flesh of the apple but a short distance, about as much as the diameter of the spot. Then the damage to the apple is principally one of disfigurement but we all know that a number one apple must be free from blemishes and so, an apple affected with this disease, no matter how perfect otherwise, will be graded as a number two or three. It has been observed that these spots are not confined to the surface but may occur at any depth in the flesh and will increase in number in cold storage. The browned tissue may have a slightly bit-ter flavor in the older spots but this bitterness is not a constant factor.
The cause of this disease is unknown thus far and careful observations in the laboratory conclude that neither fungi nor bacteria can be assigned as the cause of the spot. The disease is widespread both in Europe and the United States. The variety pre-eminently subject to it in the northeastern part of the U. S. is the Baldwin. Prof. Craig of Ottawa, Canada, reports the spot as occurring on the Baldwin, Canada Red, Northern Spy, Seek-No-Further, Tolman Sweet, Ben Davis, Fame-use and others.
Wortmann, a German investigator found that starch is present often in considerable quantity, in the brown, spongy tissue while the surrounding healthy tissue is almost, if not wholly destitute of starch. It is believed that upon death of the cells their activities ceased and the transformation of starch into sugar was arrested. This theory accounts . for the absence of starch from late formed spots. Several other investigators of this disease were, Sewart of the Geneva Experiment Station, Craig of Ottawa, Canada, Lamson of the New Hampshire Station and others.