Non-parasitic problems of cured tobacco
The final quality of tobacco leaf depends largely on the success of its production and care taken during harvesting and curing. During curing leaves may occasionally present various lesions that are not caused by micro-organisms described in the fact sheets of Pest problems.
These lesions can have quite different origins such as:
- poor quality of leaves at the harvest; one must keep in mind that leaves suffer from bad weather (droughts, floods ...) and agronomic (nitrogen excess, hardpan ...) conditions during the growth of the plants. So, the leaves with their modified chemical, structural or other characteristics, cure satisfactorily and only quite late reveal lesions introduced in the field;
- poor harvesting conditions: the harvested leaves are very fragile, the slightest contusions or too long waiting in the field will have repercussions during curing;
- poor curing and storage management of tobacco.
In the following topics the major lesions observed on dark tobacco leaves (air-cured) and Virginia tobacco (flue-cured) are detailed. Note that lesions are also observed on Burley tobacco. In fact it has many problems in common with dark tobacco, but sometimes with different symptoms.
When one is faced with such lesions, depending on their causes and initiation periods, it will probably be too late to intervene, which means that a more careful control should be undertaken during tobacco curing.