iNDIAlSrA HOETICULTUEAL SOCIETY, 426 



in other crops before planting an orctiard is, of coursfe, to be commended. 

 Perhaps in this fashion the fungus may simply be cultivated out of ex- 

 istence. » 



"In view of all that has been said, it is plain that it is not advisable to 

 replant trees in holes from which diseased ones have just been removed 

 unless perfect precautionary measures have been taken to rid the soil 

 of all traces of the mycelium. And it is even doubtful if new trees should 

 ever be planted out between the rows of diseased ones. 



"And, finally, all sporophores that are found should be burned. The 

 search for disease-resisting varieties will probably prove a failure and is 

 a method that has in similar cases not yet proven itself entirely practical. 

 The fact that this fungus and other similar ones are found as parasites 

 on such widely different species as noted above would of itself discourage 

 the attempt to secure a disease-resisting variety."— Exchange. 



BLACK KNOT OF THE PLUM AND CHERRY. 



The opinion is quite prevalent among farmers and many fruit growers 

 that the disease known as black knot, so often found upon plum and cherry 

 trees, is caused by certain insects. It is true that we may often find upon 

 cutting open these knots the larvae of certain insects, but it is a uni- 

 versally I'ecognized fact among those who have given the matter care- 

 ful attention, that these unsightly, knotty excrescences are due to a special 

 fungus which is almost always confined to the plum and sour cherry. The 

 insects are there, because they find these knots to be good breeding places. 

 The swellings are first noticed in early spring, often as soon as growth 

 begins. They are then of a yellowish color, but get darker with age. In 

 May and .Tune a crop of spores, which answer to seeds in higher plants, 

 appears on the surface of the knots, i*esembling to the naked eye a soft 

 downy covering. This soon disappears, when the knots continue to get 

 darker until winter, when they have the characteristic black color, which 

 makes them so conspicuous at this season of the year. If examined 

 carefully late in the fall, the surface of the knot will be found to be cov- 

 ered with a great many minute pimples or elevations, each one of which 

 is a fruit of the fungus in which the winter spores are contained. These 

 are in turn distributed later on, and find a lodging place in the crotches 

 of limbs and in the openings of the bark, and at the junctions of the an- 

 nual growths. As these spores germinate they send their vegetative or- 

 gans into the growing tissues of the branch causing swellings, which often 

 extend along the branches four or five inches. These vegetative tissues 

 do not all die during the winter, but some live over and so new swellings, 

 at the edges of the old ones, may be seen the following year. In this way 

 the branch may continue to be infested until finally it becomes completely 

 surrounded, when the circulation is cut off and the branch dies. 



