TO CURE THE PLUM TREE KNOTS. 



31 



^ve Tiever troubled with the cxirculio ; yet 

 many of the trees belonging to a neighbor 

 of mine are covered v/ith knots, and I am 

 xander the necessity of cutting them off my 

 own trees annually to keep them from, the 

 sam.e condition. It appears evident, there- 

 fore, in fact I may say conclusive, to my 

 mind, that the excrescence is not caused 

 by the curculio ; because, supposing that 

 insect to be prevalent here, it is not at all 

 probable that they v/ould attack the bark 

 in preference to the fruity as the knots con- 

 tinue making their appearance as long as 

 the sap is in motion. I have, until quite 

 lately, been under the iiiipression that it 

 might be caused by some other insect. I 

 therefore watched -the trees quite closely, 

 but have never discovered any insect feed- 

 ing upon, or depositing its eggs in the 

 bark of the tree. 



The fact, that the larv<z or the eggs of 

 one or two insects are sometimes found in 

 the knots, is no evidence of the insect being 

 the cause of the disease ; since the larva, 

 or the eggs, as the case may be, are not to be 

 found when the swelling first appears, nor 

 until it has become quite large and pulpy. 



I have, in consequence, arrived at the 

 conclusion that the disease is not attributa- 

 ble to the attacks of an insect. It is no- 

 thing more nor less than an impure state of 

 the sap, caused by the introduction of some 

 improper food, of a virulent and contagious 

 nature, into the circulation through the 

 agency of th« roots or leaves. 



Or, it is an ulcerous habit, peculiar to 

 those varieties of the plum, with coloured 

 fruit, v/hich makes its appearance in the 

 infancy or at an advanced age of the tree, 

 according as it may be infected. In sup- 

 port of these views, I shall state the follow- 

 ing facts : 



1st. Suckers taken from the roots of a 

 badly diseased tree, will, without excep- 



tion, eventually become diseased. On the 

 other hand, seedlings, grown from the 

 seeds of a healthy tree, will rarely be af- 

 fected, unless contiguous to trees in an un- 

 healthy state. 



2d. Buds, taken from diseased trees, and 

 inoculated on healthier stocks, have become 

 so m.uch infected as to be cut down, en- 

 tirely, the first year after being operated 

 upon ] while in other cases where the trees, 

 from which the buds for inoculating were 

 taken, were in a healthy condition, quite 

 the reverse was the result. They remained 

 healthy and sound. This I have tried re- 

 peatedly. 



It may not be amiss to state, here, that 

 the trees bearing light coloured [white or 

 yellow,] plums are seldom affected, and 

 never unless immediately surrounded by 

 diseased trees of the dark coloured varie- 

 ties. [This is perfectly true, except when 

 the disease is very wide-spread and neg- 

 lected ; the yellow sorts are then att-ack- 

 ed. Ed.] I could adduce many other 

 similar instances favorable to my conclu- 

 sions ; but I shall, at present, after propos- 

 ing a remedy which suggests itself to my 

 mind, leave the subject to some more skill- 

 ful cultivator who may take advantage of 

 the above hints. 



The remedy which I propose is to cut 

 and keep cutting, as long as the knots 

 make their appearance, covering the wounds 

 thus made with Mr. Downing's solution of 

 gum shellac, at the same time freely wa- 

 tering with copperas {sulphate, of iron) dis- 

 solved in water, at the rate of one ounce of 

 copperas to two gallons of water. This 

 maybe considered rather strong; but the 

 trees will bear it. It is a very powerful 

 disinfecting agent. I have seen it used 

 with great success on trees which were 

 given up for dead. It possesses some po- 

 tent vital principle, of which I am not suf- 



