Root-feeding insects of Senecio riddellii in eastern New Mexico and northwestern Texas.

Abstract

Five insect species were reared from roots of Riddle's groundsel (Senecio riddellii Torrey & Gray). Phaneta offectalis (Hulst) (Lepidoptera: Tortricidae), Cylindrocopturus armatus Champion (Coleoptera: Curculionidae), and Cochylis felix Walsingham (Lepidoptera: Cochylidae) were the most abundant, while only one individual each of the 2 other species, Smicronyx intricatus Casey (Coleoptera: Curculionidae) and an undescribed moth (Lepidoptera: Gelelchiidae), was reared. A survey conducted in southeastern New Mexico and northwestern Texas indicated that infestation of Riddle's groundsel by P. offectalis is widespread. Riddle's groundsel is a new host record for these 5 insect species, and these insects are naturally occurring exploiters of this rangeland weed.