Alternaria alternata: A threat to pomegranate trees in France

Alternaria alternata and Grenadiers

Alternaria alternata, a formidable pathogenic fungus, poses a major challenge to pomegranate crops in France. Its damage, both to leaves and fruit, causes significant losses, particularly on susceptible varieties such as 'Provence' or 'Acco'. While preventative and curative solutions exist, it is essential to act quickly and strategically to limit its impact. Furthermore, as a specialized wholesale supplier, we offer professional-quality pomegranate plants to offset losses caused by this disease.

Symptoms of Alternaria alternata in pomegranate trees

On fruits

The first signs of Alternaria alternata appear as circular, reddish spots on the fruit. These spots, which quickly turn black, measure between 1 and 3 mm in diameter and are surrounded by a yellowish-green halo. If the infection progresses, the lesions can cover up to half of the fruit's surface. Although the arils initially remain intact, internal rot eventually develops, making the fruit unfit for sale.

On the leaves

Infected leaves exhibit marked chlorosis, resulting in significant yellowing. This chlorosis is often accompanied by premature defoliation, weakening the tree and reducing productivity.

Development and propagation of Alternaria alternata

Conditions favorable to the disease

• High humidity and frequent rain: These factors accelerate germination and dispersal of spores.
• Natural vectors: Spores are spread by the wind, but also by insects and birds.

Sources of inoculum

• Mummified fruit, infected plant debris and contaminated soil.

Risk periods

Flowering is the most critical phase. At this stage, spores are easily deposited on the developing flowers and fruits.

Prevention in conventional agriculture

1. Fungicide treatments

• Recommended products: Copper oxychloride, propiconazole, thiophanate-methyl or azoxystrobin.
• Alternating treatments: Use different modes of action to avoid resistance.

2. Preventive sprays

Apply treatments as soon as flowering begins or as soon as the first symptoms appear.

3. Water management

Maintain good drainage and avoid excess moisture in the soil by limiting overwatering.

Prevention in organic farming

1. Bordeaux mixture

Apply this natural fungicide in spring to protect pomegranate trees.

2. Controlled watering

Reduce ambient humidity by limiting water input and ensuring effective drainage.

3. Hygiene and maintenance of the orchard

• Collecting fallen fruit: Avoid the proliferation of spores.
• Grassy inter-rows: Maintain an ecological balance while limiting the proliferation of diseases.

Treatment of Alternaria alternata

Conventional treatments

Promptly spray approved products such as copper oxychloride or azoxystrobin to stop the infection.

Biological treatments

• Bordeaux mixture: Reapply after each rain.
• Balanced fertilization: Use organic fertilizers to strengthen the tree's natural defenses.

Impact on yields and business solutions

Alternaria alternata can cause losses of 1 to 6% depending on the variety. Although these figures seem modest, the difficulty in detecting internal fruit rot can seriously impact marketing. Susceptible varieties such as 'Provence' and 'Acco' are particularly affected, while the variety 'Wonderful' shows better tolerance.

In the event of significant losses, it is crucial to quickly replace affected plants to maintain the profitability of your operation.

Grenadiverse: Your partner for tailored solutions

At Grenadiverse, we understand the challenges posed by Alternaria alternata and offer business solutions to support pomegranate growers:

• Professional quality pomegranates: Our plants, from specialized nurseries, are adapted to French conditions.
• Wide range of pomegranate trees: Bare-root, tall, potted or half-stem, our plants adapt to all your needs.
• Responsive service: Response and quote within 48 hours for all orders.
• Decreasing prices: Take advantage of attractive prices based on the volumes ordered.
• Fast and careful delivery: Your plants delivered directly to your plot in less than 15 days.

Additional benefits:

• Dedicated technical support to design your orchard.
• Personalized advice to maximize the productivity of your plantations.
• A turnkey offer for establishing or renewing your orchard.

Order now from Grenadiverse and enjoy unbeatable value for money to boost your grenade production.

FAQs

• What are the visible symptoms of Alternaria alternata? Reddish spots on the fruit, leaf chlorosis, and premature defoliation.
• What factors favor the development of the disease? High humidity, frequent rains, and infected plant debris.
• How to prevent disease in organic farming? Use Bordeaux mixture, limit watering, and maintain inter-row areas.
• Which varieties are most susceptible? 'Provence' and 'Acco' are particularly vulnerable.
• Can Grenadiverse deliver plants quickly? Yes, our plants are delivered throughout France in less than 15 days.
• What services does Grenadiverse offer? Free quotes, personalized technical advice, and a wide range of pomegranates at producer prices.

Preserve Your Cultures and Bounce Back with Grenadiverse

Alternaria alternata poses a significant challenge for pomegranate growers in France. However, with appropriate agricultural practices and professional support, it is possible to limit losses. At Grenadiverse, we provide quality plants, technical advice, and a responsive sales team to help you revive your crops and maintain your competitiveness in the market.