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Tobacco Blue Mold | ||
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Tobacco blue mold can be very devastating to tobacco plants, especially when plants are young. Usually, the first symptoms of blue mold is the appearance yellowed areas on the upper surface of leaves. During cloudy days or early morning hours, a blue gray growth may be observed on the underside of leaves. When gray growth is observed, the gray area will be covered with spores of the fungus. This is a key characteristic of blue mold. As, leaf spots age, they turn from yellow to brown and often tear or drop out. If infection has occurred near or on leaf veins when young leaves are rapidly developing, they may become deformed. Within the growing points (veins) dead areas may be observed. Dead leaf veins may cause the leaf to pucker, twist or distort. Plants infected in early season often become stunted, turn yellow and may develop necrotic areas just below the tissue of the outer stem, normally within a few inches from the the soil line. Cutting the plant just above the soil line may reveal the characteristic necrotic ring just below outer tissue of the main stalk. |
Gray moldy growth on the underside of infected leaves.
The gray growth is like a carpet of spores. |
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| Sporangiophore of blue mold | |||
