EXPERIMENT STATION BULLETINS. 2G5 



will be a wise precaution to prevent overcropping, and the consequent 

 weakening of the trees, by a judicious thinning of the fruit. 



As indicated above, whenever a knot appears it should be cut off, while 

 still but partly developed, and destroyed by fire. The cut should be 

 made several inches below the lowest point where any discoloration can be 

 seen in the wood, in order to remove all of the tissues of the fungus and 

 prevent its spread down the branches. If the knot is upon the trunk of 

 the tree, while it might be economy to remove and burn the entire top of 

 the tree, if not the ttee itself, it can generally be prevented from spreading 

 if the swelling is carefully pared away and the wound treated with tincture 

 of iodine, which seems to have the power of destroying the tissues of the 

 fungus without injuring the tree. The wound should then be covered with 

 linseed oil paint. Good results have been found from the use of the oil 

 alone but the treatment with iodine seems more efficient. 



Cut off or treat the knots whenever they are found, but careful examina- 

 tions of the trees should be made in the spring and again in the fall to 

 prevent the knots that may have escaped attention during the summer from 

 developing spores. 



To secure proper attention to the destruction of the knots, a law was 

 enacted by the last legislature, as a part of the yellows law (which is given 

 in this Bulletin under that heading). The intelligent and wide-awake fruit- 

 grower does not need to be compelled to destroy his knots, by legislative 

 enactment, but he should avail himself of its aid in securing the destruction 

 of the knots upon the trees of his criminally careless neighbor. 



PLUM BLADDERS. {Exoascus priini. Fuckl) 



The fruits of the European plums and both branches and fruit of Amer- 

 ican sorts are often attacked by a fungus causing them to swell up. The 

 fruits in particular are greatly distended, the contents are destroyed, and 

 only a hollow shell remains, hence the name. The diseased twigs and fruits 

 should be removed and burned. While entire immunity may not be secured 

 by spraying, as for the rot and shot-hole fungus, with the Bordeaux mixture, 

 there are no other known remedies. 



THE PEACH AND PLUM ROT. (Monilia fructigena. Pers.) 



Particularly in wet seasons this disease has caused frequent losses to the 

 peach-and plum-growers, the entire crops in some cases being destroyed. 

 , The apricot and cherry also are subject to the same disease. It is most inju- 

 rious to the early sorts, but few if any varieties are proof against it. In the 

 case of the cherry, and plum, the foliage as well as the fruit is attacked and 

 the young twigs, particularly of American varieties, may also be involved. 

 Not only does the presence of moisture seem necessary for the germination 

 of the spores, but the spread of this disease is in proportion to the humidity 

 of the season. The appearance of the disease is familiar to all, but it may 

 not be generally understood that the patches of yellowish-brown dust 

 seen upon the surface are the spores or seeds of the disease, by which it 

 is disseminated. When two or more fruits grow so closely together that 

 they touch, the sides in contact are generally covered with moisture, and 

 the germination of the spores is hastened ; it is a matter of general obser- 

 vation that if one fruit is attacked the rot always spreads to all fruits that 

 touch it. By the proper thinning of the fruit, the rot is made less destruc- 

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