APS Homepage

TECHNICAL SESSION: Integrated Management of Plant Diseases

Integrated management of turnip scab caused by Streptomyces spp.
Saltanat Mambetova - Michigan State University. Benjamin Werling- Michigan State University, Chad Hutchinson- TriEst Ag Group Inc, Mary Hausbeck- Michigan State University, Ray Hammerschmidt- Michigan State University, Noah Rosenzweig- Michigan State University

Turnip scab is caused by Streptomyces spp., soil-inhabiting filamentous bacteria. Turnip production for fresh market or processing in Michigan comprises approximately 429 acres. Growers reported turnips yield $3,000-$6,000/A in gross revenue in 2015 and 2016. Losses due to diseases cost growers significant revenue. Recently, turnip production in Michigan has been affected by Streptomyces spp. Therefore, the objective of this study was to develop integrated management tools for turnip scab. An experimental research trial in a commercial grower field was established with the turnip variety “Purple Top White Globe” to evaluate different rates of fumigant (chloropicrin) and two commercially available biological products. Turnip seed was planted at 1” depth into four rows by 100-ft plots and replicated four times with a randomized complete block design. Six treatments; fumigant with three different rates, two biological treatments were tested and compared to the non-treated control. Treatments were applied pre-planting and at planting. Two rows of turnip per plot were hand harvested 70 days after planting. The number of total and marketable turnips was calculated. Disease severity was measured as an index. No treatments were significantly different from the non-treated control in number of total roots. Two different rates of fumigant had significantly higher total and marketable yield compared to the non-treated control.