none The population ecology of S. graminum (Rondani) was investigated during the summers of 1979 and 1980. Population numbers of greenbug were sampled and correlated with various biotic and abiotic factors, namely, number of predators and parasites, days postplant, daily ambient air temperature means and extremes, microhabitat air temperature means and extremes, daily percent relative humidity (RH), and weekly rainfall. Stepwise regression and life table analysis methods were used. In 1979, the days postplant and coccinellid predators were of greatest significance in influencing greenbug numbers, whereas during 1980, coccinellid and Chrysopa larvae correlated significantly with changes in greenbug densities. Nutrition; Diet; Feeding; Carnivorous feeding; Predation; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Population dynamics; Habitat; Man made habitat; Abiotic factors; Physical factors; Land and freshwater zones; Nearctic region; North America; USA Coccinellidae; Chrysopa (Neuroptera ); Prey; Schizaphis graminum (Hemiptera); Predator prey interactions; Population density; Hemipteran prey population dynamics relationship; Cultivated land habitat; Sorghum fields, density & hemipteran prey dynamics; Missouri; Boone & Cooper Counties; Hemipteran prey, crop habitat Lysiphlebus testaceipes (Braconidae); Hemipteran hosts; Schizaphis graminum; Host parasite relationships; Schizaphis graminum (Hemiptera) host population dynamics; Population density, hemipteran host dynamics relationship; Cultivated land habitat; Sorghum fields, density & hemipteran host dynamics; Missouri; Boone & Cooper Counties; Hemipteran host, crop habitat Anthocoridae; Prey; Schizaphis graminum, crop habitat; Predator prey interactions; Schizaphis graminum population dynamics relationships; Population density; Hemipteran prey population dynamics relationship; Cultivated land habitat; Sorghum fields, density & hemipteran prey dynamics; Missouri Schizaphis graminum (Aphidoidea); Food plants; Sorghum bicolor (sorghum); Predator prey interactions; Insect predators; Hymenopteran parasites; Lysiphlebus testaceipes; Host parasite relationships; Lysiphlebus testaceipes (Hymenoptera); Population dynamics, biotic & abiotic influences; Life tables; Population dynamics in crop habitat, biotic & abiotic factors; Predators; Anthocoridae; Coccinellidae (Coleoptera) & Chrysopa (Neuroptera); Cultivated land habitat; Sorghum fields, biotic & abiotic factors influencing dynamics; Climate and weather; Rainfall & microclimatic influences on population dynamics; Humidity, crop habitat; Temperature; Ambient & microclimate, population dynamics relationship; Misouri; Missouri; Boone & Cooper Counties, insect parasite & predator & abiotic factors