Wednesday, December 12, 2007 - 10:41 AM

Plant-herbivore-carnivore interactions in cotton, Gossypium hirsutum: Linking belowground and aboveground

Dawn M. Olson,, USDA-ARS, Cprmu, 2747 Davis Road, Tifton, GA and Felix L. Wäckers,, Lancaster University, Centre for Sustainable Agriculture, LA1 4 YQ, Lancaster, United Kingdom.

ABSTACT Most studies on plant-herbivore interactions have focused on either root or shoot herbivory in isolation, but recent studies show how above- and below ground herbivores may interact via a shared host plant. Cotton (Gossypium spp.) produces a variety of terpenoid aldehydes that exhibit toxicity to a wide range of herbivores and pathogens. In addition cotton plants emit herbivore induced volatile compounds, both at the site of damage and systemically on all tissues above the site of damage. As these volatile compounds attract natural enemy species of the herbivore, they are considered to represent an indirect defense. We utilize Gossypium hirsutum, Heliocoverpa zea, Meloidogyne arenaria and Microplitis croceipes to determine if terpenoid induction occurs in cotton through foliage feeding, root feeding and their combination, and if foliage feeding, root feeding and their combination affect volatile induction and the ensuing attractiveness of plants for a member of the third trophic level.

Species 1: Malvales Malvaceae Gossypium hirsutum (cotton)
Species 2: Hymenoptera Braconidae Microplitis croceipes
Species 3: Lepidoptera Noctuidae Helicoverpa zea (corn ear worm, bollworm)