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Pest Guide

Symptoms, treatments and recommendations for treating alternariosis

Alternariosis

Alternaria Sp.

Pathogen:

Fungus

Type:

Risk:

HIGH

Alternariosis

Arándano

Alternaria: Symptoms and Damage in Blueberries

Damage caused by Alternariosis in Blueberry

WHO CAUSES IT?

Alternaria sp. It is a genus of fungi that includes various pathogenic species of plants. These fungi are characterized by producing dark, multicellular spores called conidia, which are dispersed by wind, rain and insects. Alternaria can survive in plant debris and soil as dormant spores, waiting for favorable conditions to germinate. When environmental conditions are suitable, such as high humidity and moderate temperatures, the spores germinate and produce hyphae that invade plant tissue. Initial infections usually occur in young, weak tissues, and the fungus spreads rapidly through the plant tissue, causing necrosis and visible lesions. As the infected plant decomposes, the fungus produces spores again, completing the infection cycle.

SYMPTOMS

The disease that Alternaria sp. produced in blueberries is known as alternariosis. This disease manifests itself mainly in the leaves, stems and fruits of blueberries, affecting their quality and yield. Early infections may go unnoticed, but as they progress, the symptoms become more evident and harmful to the plant.

- Dark necrotic Taches on leaves and fruits.
- Lesions with yellow halos on the leaves.
- Premature fall of leaves.
- Fruit rot.
- Drying of young stems.
- Decrease in plant vigor.
- Significant reduction in fruit yield.

Alternaria in Blueberries: How to Recognize and Treat It Effectively

TEMPERATURE AND HUMIDITY

20°C - 25°C

80% - 95%

TRANSMISSION PATHS

Wind, Rain, Insects, Contaminated tools, Remains of infected plants, Direct contact between plants

Do you want to remove this pest? Choose how you want to treat it.

TREATMENTS

Chemical treatment

• CIPRODINIL 37.5% + FLUDIOXONIL 25% [WG] P/P
• POTASSIUM PHOSPHONATES 51% (Exp. as phosphorous acid) [SL] P/V
• COPPER OXYCHLORIDE 35% (exp. in Cu) [WG] P/P
• PIRACLOSTROBIN 6.7% + BOSCALIDE 26.7% (I) [WG] P/P
• CUPROCALCIC SULFATE 12.4% (EXPR. IN CU) [SC] P/V

Authorized treatments in organic farming

• COPPER OXYCHLORIDE 35% (exp. in Cu) [WG] P/P
• CUPROCALCIC SULFATE 12.4% (EXPR. IN CU) [SC] P/V

Biological control

• BACILLUS SUBTILIS (STRAIN QST 713) 1.34% [SC] P/V

Recommendations

- Regularly monitor blueberry crops to detect early symptoms of alternariosis.
- Use blueberry varieties resistant or tolerant to Alternaria sp.
- Implement cultural management practices that reduce humidity in the foliage, such as drip irrigation.
- Perform appropriate pruning to improve air circulation and reduce humidity in the plant canopy.
- Remove and destroy the remains of infected plants to reduce the source of inoculum.
- Apply appropriate fungicides preventively and following technical recommendations.
- Rotate crops to minimize the accumulation of inoculum in the soil.
- Maintain adequate control of weeds, which can serve as an alternative host for the pathogen.
- Promote balanced nutrition of plants to maintain their vigor and resistance to diseases.