August 8, 2005
Underneath it All
The tastiest root
There are many insects which spend part of their lives below ground, feeding on the roots of various plants. While much is known about their above-ground lives, less is known about what they do underground. Focusing on the clover root weevil (Sitona lepidus), an insect that attacks white clover (Trifolium repens) throughout Europe and the United States, Scott Johnson, Peter Gregory (Scottish Crop Research Institute, UK), and Xioxian Zhang (University of Abertay, UK) used various techniques, including x-ray tomography, to observe the insects' plant choices. The team identified a flavanoid compound that attracted the weevils, who show a preference for N2-fixing root nodules. The talk, "What lies beneath: How do soil insects find host plant roots?" will be given by Scott Johnson during Organized Oral Session 8: Invertebrate Ecology: Butterflies and Soil Insects.Monday 8 August 08:00 "“ 11:30 EDT, Meeting Room 518 C, Level 5, Palais des congrs de Montr©al
Draped in silk
If a predator left a clue behind every time it went somewhere, prey might start to catch on. Apparently some insects have noticed that spiders frequently leave tell-tale trails of silk behind. Beetles, which could be a mighty hard catch for some spiders, avoid the presence of fresh silk, according to Ann Rypstra (Miami University, Ohio, US) and Christopher Buddle (McGill University, Quebec, Canada). In their study, Rypstra and Buddle examined the effect spider and silkworm silk had on the leaf-chewing Japanese Beetles and Mexican Bean Beetles, two herbivores that feast on snap beans. The presence of silk on snap bean leaves worked as a pest deterrent of sorts, as the beetles did less damage to the silk draped plants than the ones left bare. Rypstra will present the poster, "Silk reduces plant damage caused by pest insects," during Poster Session 24: Agroecology.
Wednesday 10 August, 17:00 "“ 18:30 EDT, Exhibit Hall 220 A-E, Level 2, Palais des congrs de Montr©al
Throwing dirt on disease
Even with a wide range of techniques and tools, diseases--both new and old--continue to plague farmers' crops. Investigating the importance of biodiversity in soil, Jean Ristiano, Bo Lui, Shujin Hu, and Marcia Gumpertz (North Carolina State University, US) compared the use of synthetic and organic fertilizers in combating the invasive soil-borne pathogen Sclerotium rolfsii, a fungus which causes Southern Blight. The group's findings will be presented during Poster Session 24: Agroecology. The title of the poster is, "Influence of microbial species and functional diversity in soils on pathogen dispersal and ecosystem process in organic and conventional agroecosystems."
Wednesday 10 August, 17:00 - 18:30 EDT, Exhibit Hall 220 A-E, Level 2 Palais des congrs de Montr©al
Genetic modification: Bacillus thringiensis (Bt) in the soil
Genetically modified Bt maize produces a protein considered toxic to certain insects that would normally damage these crops. Marko Debeljak (Jozef Stefan Institute, Ljubljana, Slovenia) and colleagues from France and Denmark examined the effects of these crops on organisms living in the soil nearby, that are not specific targets or particular pests to the crops: springtails (Collembola) and earthworms. Debeljak will discuss the results in a talk entitled, "Effects of genetically modified Bt maize on earthworms and Collembola functional groups" during Contributed Oral Session 137: Agroecology: Pest Control, Dispersal, and Pollination.
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