Rearing history affects demography of greenbugs (Homoptera: Aphididae) on corn and grain sorghum.
1990
McCauley G.W. Jr. | Margolies D.C. | Collins R.D. | Reese J.C.
Biotype E greenbugs, Schizaphis graminum (Rondani), were reared on corn, Zea mays L., to assess their ability to develop, reproduce, and survive on this host. Four corn germ plasm accessions (Antigua, OH-45, AP-670, and 2570) were studied along with a susceptible grain sorghum, Sorghum bicolor (L.) Moench, (NC + 630x) and a resistant sorghum (PI 264453) as controls. Corn-reared and sorghum-reared greenbugs were tested to evaluate the effect of host history on performance. Daily mortality and fecundity schedules were measured and net reproductive rate, intrinsic rate of population increase, finite rate of increase, and population doubling time were calculated Plant entry had a significant effect on development time for the first two instars but not the second two, which may be because of physiological adaptation to the novel hosts. All life-history measures except generation time indicated greater potential for greenbug population growth on sorghum than on corn. However, greenbugs still had sufficiently high population growth on corn to indicate that corn has a good host. Better performance on both sorghums and Antigua corn compared with the other corn entries suggested the possible involvement of the MBOA-DIMBOA complex in resistance to greenbugs. Longevity was greater and population doubling time was shorter for corn-reared than for sorghum-reared greenbugs. Host history also interacted with plant entry such that corn-reared greenbugs were more fecund on corn than sorghum-reared ones, whereas the opposite was true on sorghum. Assessment of these data indicates that greenbugs have a potential to adapt to corn as a true host and develop a biotype injurious to corn.
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