title: Trichogramma (Hymenoptera: Trichogrammatidae) ecology in a tropical bt transgenic cotton cropping system: sampling to improve seasonal pest impact estimates in the Ord River Irrigation Area, Australia.
abstract: Trichogramma Westwood (Hymenoptera: Trichogrammatidae) cause high mortality rates in the potentially resistant pest species, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and are considered integral to the resistance management plan for Bacillus thuringiensis transgenic cotton, Gossypium hirsutum L., production in the Ord River Irrigation Area (ORIA), Western Australia. Measured as percentage of parasitism, Trichogramma activity seems highly variable over time; yet, it contributes significantly to pest suppression at peak insect pest density. Environmental constraints on Trichogramma survival, especially insecticide applications, may limit their effectiveness. The decision to initiate insecticide applications in ORIA cotton crops is best delayed unless absolutely necessary to avoid disruption of Trichogramma impact on pests. Trichogramma disperse into young crops and display high intrinsic rates of increase effectively stifling Helicoverpa (Hardwick) population increase after initial egg lay during high-density years in the ORIA, and evidence suggests a possible preference for H. armigera host eggs.
authors.affiliation: School of Integrative Biology, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia. andrew.davies@ars.usda.gov
authors.forename: A P
authors.initials: AP
authors.lastname: Davies
authors.forename: U S
authors.initials: US
authors.lastname: Pufke
authors.forename: M P
authors.initials: MP
authors.lastname: Zalucki
mesh_terms: D000383:Agriculture / Q000379:methods*; D000704:Analysis of Variance; D000818:Animals; D003368:Gossypium; D007300:Insect Control / Q000379:methods*; D009036:Moths; D030821:Plants, Genetically Modified; D011157:Population Dynamics; D012621:Seasons; D014329:Tropical Climate; D014863:Wasps / Q000502:physiology*; D014904:Western Australia