The Identity of the Black Pecan Aphid, Elanocallis Caryaefoliae (Davis)

Abstract

In 1910, J. J. Davis (2) described a “velvety black” aphid, collected from hickory in Illinois and Missouri, under the name Callipterus caryaefoliae, “the tuberculate hickory plantlouse.” After examining the Fitch and Davis types, Baker (1) declared caryaefoliae to be a synonym of fumipennella Fitch which he placed in the genus Myzocallis. Subsequently a “black” aphid that has become abundant on pecan in the South was identified as Myzocallis fumipennellus (Fitch) and practically all references to the insect have been under that name. The common name, “black pecan aphid,” has been adopted by the American Association of Economic Entomologists. In their recent work on the aphids of Illinois, Hottes and Frison (6) follow Baker's opinion as to the species but recognize the genus Melanocallis which was erected by Oestlund (7) for caryaefoliae Davis. They remark, “Fitch's original description, however, fails to agree in some respects with specimens we are calling this species.” In order to identify the black pecan aphid with more certainty, the writer has studied the types of fumipennella and caryaefoliae in comparison with many additional specimens taken from pecan and other hickories. A report of these studies follows.