Tomato leaf mold | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Phylum: | Ascomycota |
Class: | Dothideomycetes |
Order: | Capnodiales |
Family: | Mycosphaerellaceae |
Genus: | Mycovellosiella |
Species: | Mycovellosiella fulva |
Binomial name | |
Cladosporium fulvum, Fulvia fulva, Passalora fulva (Pers.) (1816) Link (1816) |
Cladosporium fulvum is an Ascomycete called Passalora fulva, a non-obligate pathogen that causes the disease on tomato known as the Tomato leaf mold. P. fulva only attacks tomato plants, especially the foliage, and it is a common disease in the greenhouses, but can also occur in the field. The pathogen is likely to grow in humid and cool conditions. In the greenhouses, this disease causes big problems during the fall, in the early winter and spring, due to the high relative humidity of air and the temperature, that are propitious for the leaf mold development. This disease was first described in the North Carolina, by Mordecai Cubitt Cooke (1883), on cultivated tomato (Cooke 1883), although it is original from South and Central America. The causal fungus of tomato leaf mold may also be referred as Cladosporium fulvum (Cooke 1883), a former name.
The tomato leaf mold fungus is a specific pathogen of tomato plant Lycopersicon, this pathogen has restricted host range (host specific pathogen) that only infects tomatoes, mainly greenhouses.
The symptoms of this disease commonly occurs on foliage, and it develops on both sides of the leaf on the adaxial and abaxial surface. The older leaves are infected first and then the disease moves up towards young leaves.
Symptoms of tomato leaf mold appear usually with foliage, but fruit infection is rare. The primary symptom appear on the upper surface of infected leaves as a small spot pale green or yellowish with indefinite margins, and on corresponding area of the lower surface, the fungus begins to sporulate. The diagnostic symptom develops on lower surface as an olive green to grayish purple and velvety appearance, which are composed of spores (conidia). Continuously, the color of the infected leaf changes to yellowish brown and the leaf begins to curl and dry. The leaves will drop upon reaching a premature stage, and the defolication of the infected host will cause further infection. This disease develops well in relatively humidity levels (above 85%). When the temperature reaches optimum level for germinating, the host will be infected by the pathogen. Occasionally, this pathogen causes disease on the fruit or blossoms with various symptoms.Fruits such as green and ripe one will develop dark rot on the stem. The blossoms will be killed before fruits grow.