Final diagnosis


Non-parasitic diseases of flue-cured leaves

The surrounding tissues of many secondary veins turn dark brown to black (<b>run-back</b>).
The harvested Virginia tobacco leaves are dull grey; once cured the leaf tissues show the same default (grey tobacco).
The interveinal-tissues of this Virginia tobacco leaf show a greyish brown metallic colour. Nutritional disorder (iron and / or manganese toxicity)