The Effect of Tillage Practice and Cover Cropping Systems on Yield, Leaf Quality, and Angular Leaf Spot Occurrence in Dark Tobacco in Tennessee

Angular Leaf Spot (ALS) (Psuedomonas syringae pv. tabaci) has become an increasingly important disease in Mid-South tobacco production since 2015. Current recommendations for the control and spread of ALS are selection of tobacco varieties with low susceptibility and the use of chemical preventions, such as agricultural streptomycin. Tobacco producers have limited options in weed management and rely heavily on tillage implementation and few pre-emergent herbicides. Cover crops have proven to be beneficial at decreasing weed biomass, improving soil health, and reducing soil borne pathogens in many crops. The objectives of this project are to evaluate the impact of cover crops and tillage type in tobacco production systems on ALS occurrence, tobacco yield, and leaf quality. Field plots were arranged in a split block design with four replications. Tillage type (conventional and no tillage) was applied to the main plot and cover crop treatment (cereal rye, crimson clover, hairy vetch, and fallow) to the sub-plot. Field inoculations of ALS were applied to tobacco in 2022 and 2023 at growth stages 1108 to 1110. Inoculated tobacco was harvested and left in the experimental area to serve as ALS inoculum for the following tobacco crop. Tobacco yield was impacted by tillage type, but disease progression was not statistically influenced by cover crops or tillage type during the first year of this study. During the second year, tillage influenced disease progression with conventional tillage having lower disease than no-tillage. Research has explored mostly chemical control methods of ALS with limited success. Additional research studying the impacts of other methods, such as cultural methods, should be conducted.