256 Forty-second Report on the State Museum. [114] 



Food-plants. 



Dr. Fitch was of the opinion that the cherry aphis lived only upon 

 the garden cherry — not on any of our native or wild cherry trees, or 

 upon any other tree. This opinion has not been sustained by our 

 further acquaintance with the insect. Thus, in the year 1878, Dr. 

 Thomas found it in Illinois, covering the twigs and axils of the small 

 limbs of plum trees as well as the cherry, in confirmation of the 

 statement of its occurrence on the plum that had been previously 

 made by Mr. Walsh. 



Mr. Buckton has observed viviparous specimens of it in limited 

 number, on the black currant, showing the slight colorational differ- 

 ence of a duller body and paler cornicles. 



It is possible that this species also extends its ravages to the peach 

 tree, appearing there as a root-form infesting the roots. For many 

 years past, the roots of peach trees along the Atlantic seaboard have 

 been seriously infested with an aphis, to the extent of causing a great 

 mortality, particularly in seedling trees. The attack was naturally 

 referred to Myzus persicce, but by some has been regarded as a dis- 

 tinct species. Examples of it sent to the Department of Agriculture 

 at Washington, were pronounced by Professor Riley to be the 3Iyzus 

 cerasi of Fabricius, but in correspondence with him, the opinion is 

 expressed that before its identity with that species can be positively 

 asserted, additional study is necessary. For a notice of 31. f cerasi, on 

 the roots of peach trees, the Second Report on the Insects of New York, 

 pp. 19-22, may be referred to. 



Eemedies. 



A kerosene and soap emulsion sprayed upon the insects would 

 effectually kill all with which it came in contact. Clustered as they 

 are on the under sides of the leaves, it would be necessary to apply 

 the liquid from beneath the tree, changing position as might be nec- 

 essary in order to reach every portion of the infested foliage. The 

 statement of Dr. Fitch, that " these are creatui'es that sprinkling will 

 not cleanse from the tree — immersion must be resorted to," may have 

 been warranted by the spi-inklers then in use, but is not sustained by 

 the progress subsequently made in the discovery of insecticides and 

 improved instruments for their application. 



Strong soap-suds alone, although not entirely effectual, will mate- 

 rially reduce the aphids upon a tree — only the more hardy ones sur- 

 viving its use. 



Tobacco water, if made of sufficient strength, is claimed to be an 

 effectual remedy for the insect. It has been used with unfailing sue- 



