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49th TWC, Tob. Work. Conf., 2020, abstr. 77

Variety and fungicide program evaluation for black shank management in flue-cured tobacco in North Carolina

ROSADO-RIVERA Y.; THIESSEN L.
North Carolina State University, Raleigh, NC USA

The most economically threatening and widespread disease of tobacco in North Carolina is black shank caused by the oomycete pathogen, Phytophthora nicotianae. Long-term strategies for managing this disease are needed to limit the development of fungicide resistance and pathogen population shifts that affect host resistance. In collaboration with Kentucky and Virginia, varieties with different levels of resistance and chemistries were evaluated in flue-cured tobacco in North Carolina. Treatments were planted in 50-ft long plots with 10-ft alleys by 4 rows and arranged in a randomized complete block, factorial design with 2 factors and 4 replicates to evaluate 3 different varieties and 2 fungicide programs. Trials were in two different sandy soil locations and replicated over two years. Disease incidence was assessed every two weeks beginning four weeks after transplant. Data were summarized as area under disease progress curve (AUDPC) and final percent disease incidence. Data were analyzed using a general linear model and beta regression, means separations were calculated using Tukey’s HSD (R Studio, 2019). Preliminary data analysis suggests that using a resistant variety with a chemical rotation system reduces disease incidence in flue-cured tobacco and may help maintain the longevity of disease management tools. (Reprinted with permission)