NEW ENGLAND FARMER. 



a59 



sess so little acidity as to require no sugar. They 

 Iiave received the name of "Davis's Seedling," 

 and are destined to make as much noise among tlie 

 cultivators of this delicious fruit as any yet brought 

 into notice. — Mobile Tribune. 



INSECTS NOT THE CAUSE OF POTATO 

 ROT. 



We copy the following remarks and communica- 

 tions from the Salem Observer. Dr. Harris shows 

 conclusively that all the various theories about in- 

 sects causing the potato rot are without foundation; 

 and this has always been our view of the subject. 

 The sudden and extensive manner in which this 

 malady comes like a blast upon us over a vast ex- 

 tent of country, and sometimes nearly over the 

 whole world, clearly shows that it cannot be the 

 work of insects. Again, if insects were the cause, 

 they must be so numerous that they could be dis- 

 covered. 



THE POTATO ROT. 



The correspondence which we publish below 

 will, we think, be equally valuable and interesting 

 to a large number of our readers. The subject is 

 one whose importance to our whole community 

 cannot be over-estimated, and which has for the last 

 few years formed a staple article for newspaper 

 discussion. The large reward offered by our 

 Legislature for a solution of the mystery, has 

 brought forth one or two new theories on the sub- 

 ject, and we feel that no apology is necessary for 

 taking up considerable space with Dr. Harris's let- 

 ter. It is probable not necessary for us to inform 

 our readers that Dr. Harris is the Librarian of 

 Harvard University, and that, as an Entomologist, 

 he is acknowledged to have no superior. His re- 

 marks, theiefore, have the weight of authority to 

 support them. — Salem Observer. 



Danvers, July 8, 1851. 

 To the Editors of the Salem Observer: 



Gentlemen: — In your paper of the 5th inst., 

 there appeared a brief note, intimating the belief 

 jhat the pretended discovery of the cause of the in- 

 tury to the potato, in the small black bug menlioned 

 by Mr. Flanders, would be found a delusive hope. 

 Feeling a deep interest in this subject, I addressed 

 a line to Dr. Harris, of Cambridge, giving him 

 such a description and specimen of insects, found 

 on the potato, as I had at command; and have re- 

 ceived from him the following letter, the publica- 

 tion of which I trust the author will pardon, as 

 the subject is one of great public interest at this 

 moment. Very truly, your obt't servant, 



John W. Puoctor. 



Cambridge, Mass., July 7, 1851. 

 John W. Proctor, Esq.: 



Dear Sir: — Your description of the insects on 

 the potato vine, with the specimens (though the 

 latter had suffered some in transmission,) applies 

 well to the larvm of Crioccris trilincata, described 

 in tiie work on insects injurious to vegetation, 

 pages 95 — 9G, to which I beg to refer you for par- 

 ticulars, — at the same time thanking you for your 

 offer of other specimens if required. You may 

 be assured that this insect has nothing to do with 

 the potato rot, which, as far as I can judge, has 

 no connection with insect depredations of any kind. 



A year or two after the potato rot appeared in 

 England, a Mr. Smee thought he had discovered 

 the cause of it, in the attacks of certain plant-lice 

 or aphides, and he wrote a work on the subject, 

 and dedicated it to Prince Albert. British natur- 

 alists, however, did not sustain him in his views. 



Three or four years ago, some person sent to 

 me, through Mr. Cole, a lot of insects, which he 

 was confident were the cause of potato rot, having 

 found them in considerable numbers on the vines. 

 They proved to be the larvrc or young of a species 

 of Coccinclla, oi lady-bird as commonly called, an 

 insect innocent of all offence against vegetation, 

 and living in all its stages upon plant-lice. 



In the summer of 1849, a young farmer in Water- 

 town brought to me a slender, striped, smooth cat- 

 erpillar, (or worm as he called it,) which he found 

 burrowing in the potato-stalks. I have found the 

 same not only in potato-stalks, but in the stems of 

 the common pig-weed. It is the larva of a small 

 moth, and though capable of doing some mischief, 

 it is by no means so common or so abundant as to 

 warrant even a suspicion that it was the cause of 

 the potato-rot. 



Last summer, the farmer employed by Mr. Wm. 

 C. Bond, astronomical observer, announced that he 

 had discovered the cause of the potato disease, and 

 stated that it was occasioned by the punctures of 

 insects, great numbers of which were to be found 

 on the vines. At my request, he collected and 

 sent to me several of them in spirit. They proved 

 to be identical with the little black jumping beetles 

 that often infest cucumber vines, and which are de- 

 scribed in my book, pages 103—104. These may 

 be the same as those mentioned in your communi- 

 cation. 



I could enumerate at least half a dozen more 

 kinds of insects that are occasionally or always to 

 be found, in their season, on the potato vines, — 

 insects varying in size from the minute black Hal- 

 tica, above mentioned, to the big potato-worm, or 

 Sphinx (fiinquemacuta, — all of them destructive ac- 

 cording to the extent of their powers, but innocent 

 of the great offence, which might be charged to 

 them with as much propriety as to other insects, 

 of causing the potato disease. I will only advert 

 to one more, namely, the Baridius trinotatus, an 

 insect for whose history we are indebted to ^ lady. 

 Miss Margaretta Morris, of Germantow^n. In the 

 larva state it lives in the stemsof the potato, where 

 it is finally transformed to a little grey beetle hav- 

 ing three black dots on its shoulders. This insect, 

 though common enough in the middle Slates, I 

 have^never seen in New England, in the course of 

 30 years' observation, and am confident that it must 

 be rarely found here, if at all. Miss Morris, when 

 she first discovered its habits, thought that she had 

 detected the real culprit, but has become convinced 

 that the potato-rot is not caused by it, though tlie 

 ravages of this insect are admitted to be very con- 

 siderable. 



And now Mr. Flanders comes forth, as the 

 claimant of the premium offered for the discovery 

 of the cause and remedy for this pestilence, telling 

 his Excellency, the Governor, that "a black bug 

 preys upon the leaf until it destroys the vine and 

 causes the root to rot," &c., &c. The claimant 

 ought at least to produce his black bugs, and have 

 tliem examined by a naturalist, to sec whether 

 they are native or imported insects. 



As the potato rot has spread over Europe, and 



