Black root rot is an important disease of tobacco in Kentucky, causing estimated annual losses in excess of $6,000,000. It rarely causes spectacular damage in any one burley field since the recommended burley varieties have some degree of resistance to the causal fungus. However, in dark tobacco plantings damage may be extensive, especially where susceptible varieties are still planted. Still, the inability to see widespread damage from black root rot is misleading. A 5% yield reduction results in a high dollar loss because the acre value of the crop is great. In addition to the reduction in yield, a lower quality crop may result from the slower growth and later maturity of diseased tobacco. The later maturing crop runs a greater risk of being cured under unfavorable curing conditions.
Smiley, Jones H.; Nesmith, William C.; and Palmer, Gary K., "Black Root Rot in Tobacco" (1986). Agriculture and Natural Resources Publications. Paper 22.