AN APHIS ATTACK ON PEACH-TREES. I9 



This occurrence of the species at West Farms is of no little interest, 

 as it had never before been reported in the United States. 



In the report of the Commissioner of Agriculture for the year 1884, 

 at page 410, Prof. Riley has published a brief notice of this discovery. 



An Aphis Attack on Roots of Peach-trees. 



Notice of an aphis attack upon the roots of seedling peaches has 

 been communicated to me by Mr. Lorin Blodget, of Philadelphia, Pa- 

 The injury to the trees was first noticed in the year 1881, but its cause 

 remained unknown until the early part of July, 1884, when upon pull- 

 ing up a seedling peach-tree just beginning to wilt, its stem for an inch 

 below the surface was found to be crowded with dark colored aphids: 

 numbers of ants were associated with them. In following up this dis- 

 covery — of a hundred trees examined, one-half at least were found so 

 seriously injured that they were past recovery and were accordingly 

 destroyed. It was doubtful if any of the remainder could survive the 

 attack. In one instance, some aphids were discovered above ground, 

 upon the succulent shoots about a foot long, of a three-year-old tree, 

 which were densely crowded with them, presenting "a singular sight, 

 with their black, shining backs, covered with ants and with large flies 

 often upon them." During forty years' growth of seedling peaches, no 

 injury of this character had been observed before this attack. 



Some examples of the insect sent to me, were dead when received 

 and in otherwise poor condition. They were Avingless, entirely black, 

 although said when living to be brownish-black. The species evidently 

 belonged to the genus Myzus, and probably (the material being too 

 poor for positive determination) to persiccB of Sulzer. A letter to Mr. 

 Blodget expressing this belief, was subsequently handed by him for pub- 

 lication to the Gardener's Monthly and Horticulturist, for September, 

 1884 (xxvi, p. 271-2). 



Mr. Blodget claims for this species a remarkable power of endurance 

 of cold, — that it lives and thrives all winter. So late as the 25th of 

 October, after a severe frost, a shoot of a peach-tree cut off close to the 

 ground, was entirely black for six inches of its length with the insect in 

 lively condition. This was sent to the Department of Agriculture, at 

 Washington, for examination. Answer was returned that it had been 

 referred to Professor Riley, and the aphis pronounced by him to be 

 Myzus cerasi of Fabricus, which he had long known as injurious to 

 peach-trees, especially to young ones in the nursery, by working on the 

 roots. 



An earlier notice of the operations of what was probably the same 

 insect upon the roots of peach-trees, was given by Mr. Glover on page 37 



