Insect Fauna of the Heads and Stems of Native Sunflowers (Asterales: Asteraceae) in Eastern North Dakota

Abstract

Insect fauna from the heads (capitula) and stems of six native sunflower species in eastern North Dakota and western Minnesota are reported. Eight insect species in six families of Coleoptera, Diptera, and Lepidoptera were recovered from the heads of six species of Helianthus . Heads of Helianthus annuus L. contained the greatest diversity of insect species. Insect species collected were also commonly found as pests of cultivated sunflower heads. Two major pests of commercial sunflower in the Great Plains—the red sunflower seed weevil, Smicronyx fulvus LeConte; and the banded sunflower moth, Cochylis hospes Walsingham—were collected from the heads of all six native Helianthus species, although they were most common in H. annuus . Neotephritis finalis (Loew) also occurred in the heads of all Helianthus spp. examined. Insects from seven overwintering species were recovered from the stems of all six Helianthus spp. Insect stem fauna diversity was greatest in H. maximiliani Schrader, and least in H. rigidus subrhomboideus (Rydberg). The sunflower stem weevil, Cylindrocopturus adspersus (LeConte), was the only major insect pest of cultivated sunflower that was recovered from sunflower stems. It was most abundant in H. annuus . A single species of parasitoid, Nealiolus curculionis (Fitch), was reared from sunflower stem weevil larvae. Results suggest that some species of Helianthus have high potential as sources of insect resistance for incorporation into commercial sunflower.