386 



DOMESTIC NOTICES. 



ly indicate to me the cause of this species of blight. 

 Frozen sap it could not have been, as two of the 

 trees were imported and set out in the spring, after 

 all frosts were over, and the new wood was inva- 

 riably first attacked. The sun's rays could not 

 have induced the disease, for if so all the limbs of a 

 particular tree would probably have been affected 

 at one time, and the Bartlet was not affected until 

 September, when the sun's rays have comparative- 

 ly little power, and its limbs attacked at different 

 times. But does not the discovery of the vermin 

 settle it conclusively ? It does to my mind. And 

 the remedy is as certainly indicated — that is, am- 

 putation with a clean knife several inches below 

 any appearance of discoloration. I say with a 

 clean knife, because I am certain from observa- 

 tion that the small quantity of diseased sap which 

 adheres to the blade is sufficient to poison a healthy 

 limb. 



As to the theory of frozen sap blight, and sun- 

 blight, for the other and by far the most serious 

 blight of the pear tree — that which first makes its 

 appearance on the body of the large branches and 

 the trunk of the trees — I do not as yet intend to ex- 

 press myself. I only wish at present to propound 

 a question or two for response from yourself and 

 Mr. Ernst. 



If frozen or scalded sap causes this form of 

 blight, why is that as a general rule, bearing trees, 

 or those of bearing age, are the only ones attacked ? 

 That this is so, experience has abundantly proved. 

 I have now growing over two hundred and twenty 

 varieties of the pear, and probably more than five 

 hundred trees, full four-fifths of which are young 

 and have not yet borne. I have never known a 

 case of this species of blight attacking a tree which 

 had not blossomed or borne fruit. Ought not the 

 bark of the young tree to be more sensitive to such 

 influences than the mature and hardened bark of 

 older trees ? I am perfectly well aware that the 

 outer bark of young trees is often, as it were, 

 burned by the winter sun, but this is not blight ; 

 for it is always seen in early spring and with pro- 

 per care, that is, excision of theinjured bark and a 

 coating of shellac over the wound, seldom or ever ma- 

 terially injures the tree. That it may be understood 

 what I mean by blight, allow me to describe it as it 

 appeared among my trees at Albany last summer. 

 In its first stage the outer bark of a large limb or 

 trunk of a bearing tree showed separate or contin- 

 uous patches of a dark brownish colour, with rais- 

 ed or circumscribed edges, presenting precisely the 

 appearance of an erysipelatous inflammation in the 

 human subject. If cut into there was an abundant 

 exudation of viscid and nauseous sap, emitting a 

 peculiar odour. In a few hours this stage of the 

 disease passed, when the bark became shrunken 

 and assumed a much darker color, verging to black. 

 If discovered in a limb during the first stage, am- 

 putation at the junction of the limb and trunk check- 

 ed it in some cases, but if the trunk was attacked 

 we left it to nature. In most cases the tree was 

 completely killed in a short time, but in some a 

 lineof demarkation formed a few inches above the 

 ground, when new buds bursted and threw out limbs. 

 At that stage I amputated near the new bud and 

 covered the wound with shellac. Those trunks ap- 



pear now to be in a healthy state. The disease 

 made its appearance in June and continued to show 

 itself throughout the summer and autumn. Trees 

 of many varieties were attacked — those native to 

 the country as often as those of foreign origin. Mr. 

 E. excepts Seckels from the disease in Ohio, but I 

 cannot do this for Albany, as they appeared to suf- 

 fer equally with other varieties. Last winter was an 

 unusually mild one for this climate ; peach trees, 

 which are generally injured, were not winter-killed 

 in the least. From this fact you can draw your 

 own inferences. Yours, very truly, Hervian Wen- 

 dell. Albany, January \Qth, 1848. 



Remarks. — We stated, in commenting on Mr. 

 Ernst's excellent article in our last, that we differ- 

 ed with him with respect to insect blight, we believ- 

 ing insects to be a fertile cause of one form of 

 blight in some portions of the country. The able 

 article (see page 3i-5) of Dr. Harris, of Harvard 

 University, one of the most skilful and accurate ob- 

 servers in the country, reaffirms and settles this 

 point. 



It is perhaps well enough to repeat here that, 

 from various sources of information, we are inclin- 

 ed to believe that the insect blight is much more 

 prevalent in the sea-coast states than in the west- 

 ern states. 



Dr. Wendei.i. is no doubt quite correct in sup- 

 posing the pear blight, which was last year so de- 

 structive to this tree about Albany, to have been 

 partly owing to insects. After perusing Professor 

 Harris's contrasts of the characters of the differ- 

 ent forms of blight, he will no doubt be able to 

 judge more accurately how far insects must be held 

 accountable for the disease in his trees. 



We are still, however, strongly inclined to be- 

 lieve that frozen sap was the cause of blight in 

 some of the large trees in his grounds. " A mild 

 winter" — that is, a winter with sudden and great 

 fluctuations of temperature — in a climate like that 

 of Albany, is perhaps more fatal to a tender-barked 

 tree than one of uniform low temperature. Take 

 the present season for example. The winter here 

 has been one so mild that there has scarcely been a 

 week that the transplanting of large trees might 

 not have been carried on — the ground being only 

 frozen two or three inches. Yet at Albany, on the 

 12th or 13th of January, the mercury sunk as low 

 as 22deg. below the zero of Fahrenheit. This was 

 perhaps followed by bright weather, and in trees 

 exposed fully to this great alternation of frost and 

 sun, we think frozen sap blight would be very like- 

 ly to occur. 



We have seen himdreds of young pear trees, two 

 years old, killed nearly to the ground with frozen 

 sap blight. But with the more active vital powers 

 possessed by them, they more easily recover from 

 its effects, when the diseased parts are amputated, 

 than older trees. 



Our own observation leads us to coincide with 

 Mr. Ernst in considering the Seckel usually al- 

 most exempt from the blight. But when a disease 

 occurs in a neighborhood, in a more than usually ma- 

 lignant form, individuals usually exempt often fall 

 victims to it — and this, we think, accounts for the 

 exception stated by him, to the general sound health 

 of the Seckel pear tree. 



