Many foliar diseases usually appear first as yellow spots and progress to dead areas within the leaf. The spots may also enlarge with time. Table 1 lists symptoms and damage patterns associated with many commonly seen tobacco problems. The causes of plant injury differ during the growing season. For example, wireworms and cutworms attack recently transplanted tobacco, and the resulting injury occurs early in the season.
Problems associated with poor root growth also occur during the first month of the season.
In general, chemical injuries from soil carryover or misapplication also are seen early in the season. Chemical injuries from drift may occur any time. It may be of help in diagnosing problems to know the spraying schedules for the crops surrounding the tobacco field. Nutrient deficiencies usually occur after the first month. For each field, all survey and scouting information should be combined into a field history.