Abstract
Pseudomonas syringae pv. tabaci tox– is the causal agent of angular leaf spot in dark tobacco. Since 2015, angular leaf spot has become the most significant foliar disease of dark tobacco production in Kentucky and Tennessee. Dark tobacco producers utilize streptomycin sulfate as their primary chemical control for the management of this bacterial disease. Resistance to streptomycin sulfate in P. syringae pv. tabaci isolates from dark tobacco fields in western Kentucky was first observed in 2015. Field trials were developed to evaluate the efficacy of alternative active ingredients compared with streptomycin sulfate. Field trials were conducted in 2020, 2021, and 2022 to evaluate the efficacy of streptomycin sulfate, laminarin, cuprous oxide, Reynoutria sachalinensis, peroxyacetic acid, polyoxin D zinc salt, Ulocladium oudemansii strain U3, and acibenzolarS-methyl for control of angular leaf spot. In all trials, dark tobacco variety KT D8LC was utilized, as this tobacco variety had previously shown high susceptibility to angular leaf spot. There are no dark tobacco varieties resistant to angular leaf spot. Plots in all years were inoculated with a streptomycin sulfate-sensitive isolate of P. syringae pv. tabaci. Data analysis showed that the streptomycin sulfate performed similarly to most other treatments. No treatment completely eliminated this bacterial disease, but based on these results, cuprous oxide and U. oudemansii strain U3 are suitable for management of angular leaf spot. Implementing a spray regimen with varying active ingredients and modes of action is key in preventing pathogen resistance and decreasing the intensity of angular leaf spot.
| Original language | English |
|---|---|
| Pages (from-to) | 5-11 |
| Number of pages | 7 |
| Journal | Plant Health Progress |
| Volume | 26 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2025 |
Bibliographical note
Publisher Copyright:© 2025 The American Phytopathological Society
Funding
Funding: Support was provided by the Altria Client Services. Support was provided by the Altria Client Services. The authors would like to thank the University of Kentucky Research and Education Center and Murray State University for allowing the utilization of land and curing barns to conduct these research trials. We would also like to thank Bobby Hill, Chris Rodgers, Caleb Perkins, Miranda Rudolph, and Natalia Martinez for all their assistance during the growing season. The authors would also like to thank Brenda Kennedy for her help in the screening of isolates.
| Funders | Funder number |
|---|---|
| Altria Client Services LLC | |
| University of Kentucky Research Committee |
Keywords
- AUDPC
- Pseudomonas syringe pv. tabaci tox
- angular leaf spot
- disease ratings
- quality grade index
- yield
ASJC Scopus subject areas
- Plant Science
- Horticulture