Alternaria alternata

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  Alternaria alternata

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  Alternaria spore chain at 160X magnification

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  Alternaria spores at 160X magnification

Alternaria alternata

Alternaria alternata is a fungus belonging to the genus Alternaria. It is a common saprophytic fungus that is widely distributed in the environment and is known to be an important allergen in humans. A. alternata is also a plant pathogen, causing diseases in a variety of crops.

Morphology

Alternaria alternata produces dark, multicellular conidia with transverse and longitudinal septa. The conidia are typically ovoid to obclavate in shape and are borne in long chains. The colonies of A. alternata are usually dark green to black, with a velvety texture.

Habitat

Alternaria alternata is commonly found in soil, air, and on decaying plant material. It thrives in warm and humid environments and can be isolated from indoor and outdoor air, as well as from various surfaces.

Pathogenicity

Alternaria alternata is a well-known plant pathogen that affects a wide range of host plants, including tomato, citrus, and apple. It causes diseases such as leaf spots, blights, and fruit rots. The fungus produces mycotoxins that can be harmful to plants and animals.

In humans, A. alternata is a significant source of allergic reactions, particularly in individuals with asthma or allergic rhinitis. The spores of A. alternata are airborne and can trigger allergic responses when inhaled.

Medical Importance

Alternaria alternata is recognized as an important allergen in humans. It is associated with respiratory allergies and can exacerbate conditions such as asthma. The allergens produced by A. alternata are potent and can lead to severe allergic reactions in sensitive individuals.

Control and Management

Controlling Alternaria alternata in agricultural settings involves the use of fungicides, resistant plant varieties, and cultural practices that reduce humidity and leaf wetness. In indoor environments, reducing humidity and improving ventilation can help minimize the presence of A. alternata spores.

Related pages

• Fungus
• Allergen
• Plant pathogen
• Asthma
• Mycotoxin