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Poster Presentations


Poster Presentations


High volume aerial sampling for low incidence detection of Phakopsora pachyrhizi spores in the planetary boundary

Presenter: Gary C. Bergstrom(2)

Other authors and affiliations: Elson J. Shields(1), Mary E. McKellar(2), Molly Swartwood(2), Patty Clement(2). (1)Cornell University, Entomology, Ithaca, NY 14853, U.S.A.; (2)Cornell University, Plant Pathology, Ithaca, NY 14853, U.S.A.

Alternatives to the soybean rust sentinel plot system need to be developed that can be executed with fewer personnel. We attempted ultra-high-volume (120 m3 of air per 15 min) sampling of the planetary boundary layer of the lower atmosphere for the presence of spores present at very low incidence. We utilized remotely piloted aircraft fitted with four spore-sampling devices that were opened at 60 m aboveground by remote control. The collection substrate was a glycerol-coated polycarbonate filter cemented to a petri plate. DNA was extracted from filters and P. pachyrhizi was identified by quantitative real-time PCR using primers Ppm1/Ppa2 and the FAM probe. Of 26 flights in Freeville, NY, from July through August 2007, samples collected on August 16 and 29 tested positive for P. pachyrhizi by PCR. Attempts to incubate spores from rinsed filters onto detached soybean leaves did not result in infection, so captured spores were presumed to be nonviable. Rust was not detected in a sentinel soybean plot or in the Syngenta spore trap at the same location. Ultra-high-volume atmospheric sampling coupled with PCR detection and spore viability testing holds great promise in regional early detection systems for soybean rust.

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