title: Effect of Bt-cotton on chrysopids, ladybird beetles and their prey: aphids and whiteflies.
abstract: The effect of Bt-cotton, i.e. genetically modified cotton that contain genes expressing delta-endotoxin, on aphid, whitefly, chrysopid and coccinellid populations was determined with a two-year field study at a cotton farm near Marble Hall, South Africa. Although Bt-cotton is lepidopteran specific, non-lepidopteran arthropod populations may be indirectly influenced by the endotoxin. Abundance of aphid, whitefly, chrysopid and coccinellid populations and predator-prey interactions were used as measures to determine possible effects on the populations under investigation. The cultivation of Bt-cotton had no effect on aphid, whitefly, chrysopid or coccinellid abundance. Positive density dependent interactions occurred between aphids and coccinellids which were not influenced by Bt-cotton. A significant relationship between whitefly and coccinellid abundance, i.e. predator-prey reaction, occurred in the control and sprayed non-Bt cotton fields but was absent from the Bt-cotton fields.
authors.affiliation: Department of Zoology & Entomology, University of Pretoria, Pretoria, 0002, South Africa. magdel.mellet@bayercropscience.com
authors.forename: M A
authors.initials: MA
authors.lastname: Mellet
authors.forename: A S
authors.initials: AS
authors.lastname: Schoeman
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects / Q000502:physiology; D001517:Coleoptera / Q000187:drug effects / Q000502:physiology*; D004175:Diptera / Q000187:drug effects / Q000502:physiology*; D017753:Ecosystem; D004726:Endosulfan / Q000494:pharmacology; D020387:Food Chain; D003368:Gossypium / Q000235:genetics* / Q000502:physiology*; D006430:Hemiptera / Q000187:drug effects / Q000502:physiology*; D007306:Insecticides / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000502:physiology*; D011156:Population Density
chemical_list: D007306:Insecticides; D004726:Endosulfan