AMERIGANA 



VOL. VI.. BROOKLYN, NOVEMBER, 1890. 



No. 11. 



THE BLACK PEACH APHIS. 



A new species of the genus Aphis. 



By Erwin F. Smith, Sc. D., Washington, D. C. 



(Continued from p. 103, vol. vi.) 



My attention was first called to this aphis in the Summer of 

 1887. Since then I have observed it repeatedly, my line of scientific 

 inquiry having kept me in the peach orchards of the eastern United 

 States almost continuously each year during the season of growth. 

 I saw it first upon the roots of the peach and did not find any upon 

 the parts above ground for more than a year. 



This aphis is not restricted to any portion of the root system, 

 but it prefers the smaller and younger fibres which admit of easy 

 puncture. Upon these the insect congregates and multiplies. Some- 

 times the rootlets are entirely covered for an inch or two and com- 

 pletely sapped, the remoter portions becoming flabby and devitalized. 

 Generally, however, I have found these root aphides in smaller 

 colonies; sometimes it has required much digging to find any; and 

 in a few instances I have failed altogether, when, fi-om the appear- 

 ance of the trees, I had every reason to suspect their presence. 

 From these observations I conclude that they are more abundant at 

 certain times of the year than at others. The character of the soil 

 also appears to have some influence on their prevalence. They are 

 most abundant and most destructive on light sandy lands, such as 

 occur in southern New Jersey, and in the middle and southern parts 

 of the Chesapeake and Delaware peninsula. I have, however, seen 

 them on roots taken from the stiff" clay a foot below the surface. 



Entomologica Americana. Vol. IV. 



NOVEMEKR, 1S9O. 



