Insect Pollinators of Carrots in Utah

Abstract

IN THE course of observation at Logan, Utah, on the occurrence and pollinating activities of insects on carrots grown for seed, 334 species representing 71 families, were collected. Most numerous in species were the hymenopterous families and superfamilies Sphecidae, Apoidea, Psammocharidae, Vespidae, and Ichneumonidae, and the dipterous families Syrphidae, Tachinidae, Bombyliidae, Stratiomyidae, and Sarcophagidae. Most numerous in individuals were the dipterous families Syrphidae, Ceratopogonidae, Chloropidae, and Piophilidae and the coleopterous family Coccinellidae. Families and superfamilies represented by the most efficient pollinators were Apoidea, Sphecidae, Syrphidae, and Stratiomyidae. Abundance times efficiency was used as a pollination index for each species. On this basis the most important genera of Apoidea were Apis: Andrena, Halictus, Chloralictus, and Colletes; of Sphecidae, Cerceris, Lindenius, Philanthus, Nysson, and Sceliphron; of Syrphidae, Syritta and Tubifera; of Stratiomyidae, Eulalia and Stratiomys. Honey bees (Apis mellifera L.) were efficient pollinators, but they were only minor factors in the Logan area because of their scarcity on carrot flowers. In most areas a combination of honey bee colonies adjacent to carrot seed fields and elimination of competing bloom may be the most practical method of increasing carrot pollination.