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NEW ENGLAND FARMER. 



465 



THE POTATO ROT— ITS CAUSE AND 

 CUEE. 



The opinion is general, we believe, that the 

 potato rot is caused by atmospheric influences — 

 •we thought so until 1855, when Lyman Reed, 

 Esq., then of Waltham, Mass., but now of Mary- 

 land, placed before us evidence that we could 

 not resist, that it is caused by an insect. In 

 1847, Mr. Alfked Smee, surgeon to the Bank 

 of England, investigated the matter with tire- 

 less assiduity, which resulted in the conviction 

 that the rot was occasioned by an insect, and the 

 publication of a book of 150 pages — but Mr. 

 Smee suggested nothing as a remedy beyond 

 picking the insect from the potato before plant- 

 ing it. 



Mr. Reed has a remedy, upon which he has 

 obtained a patent. Mr. Smee and Mr. Reed both 

 impute the mischief to an insect which they call 

 the Aphis Vastator. 



More recently, Mr. Alexander Henderson, 

 of Buffalo, N. Y., has discovered that the Phy- 

 tocoris Linealaris of P. de Barroe, or the Capris 

 Obliniaius of Say, is the cause of the potato rot. 



In that excellent journal of science and art, 

 the Scientific American, we find some illustrations 

 of the potato leaf and tuber, and the insects up- 

 on them, and an extended history of the discov- 



ery. We have thought the subject of sufficient 

 importance to justify us in incurring the expense 

 of the engravings which are beneath presented, 



and with such portions of the history as we can 

 find room for. In our next paper we propose to 

 give Mr. Reed's history of his discovery. The 

 American says : — 



"One thing appears certain : Mr. Henderson 

 has discoved that the Phytocoris are the primary 

 cause of the potato rot, strictly so called, which 

 first appeared in 1845, and which is identical 

 with that of the present season. 



If a tuber be examined with a microscope just 

 before planting, on it may be seen a small, yel- 

 lowish, translucent oval object, secured, as is 

 common with insects' eggs, by a gummy substance 

 to the potato. This will produce unsound pota- 

 toes, and the egg is that of the Pliyiocons. — 

 When the tuber is plarited at the ordinary depth, 

 this egg hatches, but if the potato is planted 

 deep, the egg is killed, and therefore deep plant- 

 ing is one remedy, because air and light are pre- 

 vented from coming to the delicate egg. After 

 a sufficient amount of warmth and moisture has 

 been obtained by the egg, the shortest time that 

 has yet been observed being six days, the shell 

 opens along its greater axis, and out comes the 

 small insect, without wings, from about the twen- 

 tieth to a twelfth of an inch long. It has sis 

 perfect legs, two attenufe, a proboscis and a pair 

 of brilliant black eyes. The proboscis is about 

 two-thirds of its body in length, and one-third 

 of its length from the head is thick, seen coiled 

 upon itself at c, Fig. 3 (which is an enlarged 

 view of the perfect insect, taken, with the other 

 views, from actual plants, tubers and insects, 

 brought to us by Mr. Henderson,) and the re- 

 mainder is flexible and needle-like. It contains 

 three tubes, through one of which it sucks up 

 the juice of the plant for its nutriment ; through 

 another it probably ejects a poison into the plant, 

 and through the other it may perform part of its 

 respiration. The young insect being born alive, 

 instantly requires nutriment, and commences 

 feeding upon the seed, which, without the young 

 are very numerous, does not. perceptibly inter- 

 fere with its growth. According to the amount 



