ABSTRACT
A large number of insect species are associated with alfalfa fields, many of which are beneficial to the crop. The beneficials include insects essential to the pollination of alfalfa flowers and predators and parasitoids of herbivorous species. The use of insect-resistant cultivars to control insects that damage both quantity and quality of the alfalfa crop is a well-established practice. The genus Medicago contains more than 60 species, two-thirds of which are annuals and one-third perennials. The National Plant Germplasm System alfalfa collection is maintained by the United States Department of Agriculture-Agricultural Research Service, Western Regional Plant Introduction Station, Washington State University, and Pullman, Washington. A wide range of intra- and inter-population breeding methods have been used but phenotypic recurrent selection in random mating populations has been especially successful in developing resistance to insects. The potato leafhopper causes extensive losses to the second and successive crops of alfalfa in much of the midwestern and eastern United States.
