Seasonal patterns ofLygus hesperusKnight abundance and distribution were observed at two conifer nurseries in western Oregon during 1985.Lygusabundance differed significantly among conifer seedling types (age class/species combinations) and sampling dates. Highest densities were observed in lodgepole pine and ponderosa pine seedlings germinated during 1985, in Douglas-fir seedlings germinated in 1984 and in late July samples. Significant interaction between seedling type and sample date reflected a shift inLygusoccurrence among seedling types during the growing season, especially from 1984 Douglas-fir seedlings early in the season to 1985 seedlings later in the season. This shift coincided with dispersal of the firstLygusgeneration and with pruning of the 1984 seedlings for height control. These results indicate thatL. hesperusabundance and distribution in conifer nurseries result fromLygusphenology in combination with seasonal changes in the spatial pattern of available resources. Implications for nursery management are discussed.