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Poster: Biology & Disease Mgmt: Nematology


Cover cropping affects plant-parasitic and free-living nematodes in Michigan carrot production
Z. GRABAU (1), Z. Maung (1), D. Noyes (1), D. Brainard (1), D. Baas (2), B. Werling (3), H. Melakeberhan (1) (1) Michigan State University Department of Horticulture, U.S.A.; (2) Michigan State University Extension-St. Joseph County, U.S.A.; (3) Michigan

Cover crops are often used for reducing soil erosion, retaining soil nutrients, and building organic matter. Free-living nematodes (nematodes that do not feed on plants) are well-established bioindicators and may respond to changes in soil ecology due to cover cropping. Some cover crop cultivars are also marketed for managing plant-parasitic nematodes. This study assessed the impact of common Michigan cover crops on plant-parasitic and free-living nematodes in carrot production systems. Research was conducted at 4 sites in Michigan where cover crops were grown in the fall preceding summer carrot production. Oats, ‘Defender’ radish, dwarf essex rape, a mixture of oats and ‘Defender’ radish, and a fallow control were treatments at each site. Black oats and ‘Graza’ radish were also grown at sites 3 and 4 while ‘Image’ radish was grown only at site 4. Lesion nematode (Pratylenchus sp.) was present at all four sites. At sites 1, 3, and 4, lesion nematode densities were relatively small (less than 20 nematodes/100 cm3 soil) and not significantly (P > 0.05) affected by cover crops. At site 2, during carrot production, lesion nematode density was significantly (P < 0.05) greater following ‘Defender’ radish than fallow or other cover crop treatments. Similarly, at site 2 during carrot production, free-living nematode densities were greater following ‘Defender’ radish or oats than fallow, but were not significantly affected by cover crops at the other sites.