47th TWC, Tob. Work. Conf., 2016, abstr. 61

Determining black shank resistance in tobacco varieties grown in Atkinson and Coffee counties in 2013-2015

BARNES T.(1); VON WALDNER M.(1); EDWARDS P.(1); BERTRAND P.(1); MOORE J.M.(1); LEWIS R.S.(2)
(1) University of Georgia, Pearson GA USA; (2) North Carolina State University, Raleigh NC USA

Black shank re-emerged as a serious problem in 2014. Varieties counted on for resistance, mainly GF-318 and NC-196 were found to show less resistance than expected even where Ridomil Gold was used. Follow-up testing found 30 isolates of Phytophthora parasitica were fully sensitive to Ridomil Gold. Trials were conducted in 2014 and expanded in 2015 to look for varieties that might show a higher level of resistance than growers are currently using. Each trial was a randomized complete block with four replications of each variety. All trials included K-326 (low resistance) and NC-196 (moderate resistance) for comparison. Trials done in 2014 found GL-395, CC-143 and NC-925 showed some promise. Trials conducted in 2015 found these and a few other varieties that warrant further testing. Nothing has been found that will stand alone without a chemical treatment program. All varieties tested to date have shown significant loss under very high disease pressure. (Reprinted with permission)