Taxonomic and Ecological Characteristics of Crop Pests in Colorado

Pest species assemblages associated with vegetable, field and forage, ornamental, fruit, and tree crops in Colorado were surveyed. Analysis of species richness on crop plants indicated that the insect orders Coleoptera, Lepidoptera, and Homoptera contained most crop pests. The insect family with the most pest species was Aphididae. Total pest species richness was correlated with major pest species richness. Frequently occurring species were determined for each crop type; there was little overlap among dominant pest species assemblages. Foliage- and stem-feeding pests were more common than trunk-, fruit-, and root-feeding species. Polyphagous species comprised ca. 70% of the species in crop pest species assemblages. but only about one-third of the total pest species list. Sequential evolution may be more common than coevolution in crop systems, due to artificial selection pressure imposed by plant breeders.