1847.] Blight in Fruit Trees. 83 



•which are remarkably vigorous begin to curl and lose their 

 bright green, as it' another attack had commenced. A lew 

 days will determine the tact. We may remark, too, that the 

 beautiful and vigorous pines of Mount Hope, the residence of Mr. 

 Prentice, exhibit the same phenomena as the fruit trees. The 

 terminal branches in these pines is the seat of the disease. It 

 does not seem to extend to the large branches. One fact in re- 

 gard to Mr. Prentice's garden and orchard ought not to be forgot- 

 ten; viz., that he uses much stimulating, azotized manure from 

 his establishments. It is not stated, however, as proving that 

 high living in the case of vegetables predisposes to the blight; 

 and yet, it appears that some of the worst cases of the potato dis- 

 ease have happened when they have been highly manured. The 

 effect of rich manures, especially those abounding in organic 

 matter, deserves consideration. Comparative observations are 

 ■wanted to make out the case for us; but certainly there is sojue 

 proof derived from the analogy of things, that vegetables may be 

 so far over-stimulated by certain manures as to render them more 

 susceptible to the causes of disease. Analogy, how^ever, must not 

 lead us astray. A vegetable has but few, if any, of the proper- 

 ties of the animal; and we may not certainly conclude, that be- 

 cause a good liver becomes fat and subject to gout and dropsy, 

 that a tree from an abundance of food will become corpulent and 

 liable to perish from a surplus of food. 



Another important rule of practice which seems to be establish- 

 ed, is that it is better to wait until the termination of the disease 

 before the dead parts are removed. The rule will enable us to 

 save much of the tree which would be sacrificed if the limbs are 

 removed at random; and since experience proves that there is no 

 danger of an extension of disease from their remaining, the pro- 

 priety of this course need not be urged. 



There is still another species of blight which attacks fruit trees. 

 It might be called the leaf blight, inasmuch as it first begins in 

 the leaf. The branch does not necessarily perish, — frequently it 

 does. Most of the leaves curl, dry up and fall off; if they all fall 

 off the limb necessarily dies. This affection differs from the pear 

 blight in this: the limb maintains its color, except that it is dry. 

 There is no appeaiance of gangrene; and if one or two leaves 

 are saved the limb will not die. In the pear blight, which af- 

 fects the limb so remarkably, gangrenous patches are common 

 and the leaf seems to die from an obstruction of the flow of sap. 

 In the leaf blight, on the contrary, the death of the leaf is the 

 cause of the death of the branch, by checking the flow of the sap 

 into the branch. The elm is more subject to this disease than any 

 of our forest trees, except the buttonwood. The disease is con- 

 fined to those which we believe are cultivated; at least, they 

 seem to suffer more than those which have not been transplanted. 



