Scab and Grenadiers

Apple scab, a well-known fungal disease in fruit crops, also affects pomegranate trees in France. Although the causative agents vary and are sometimes unknown in this species, its symptoms and management approaches share similarities with other crops. Apple scab can significantly reduce fruit quality and market value. In this article, we examine the symptoms, conditions favorable to its development, as well as prevention and treatment practices in organic and conventional agriculture. In addition, we present solutions to help producers restore their affected orchards.

Symptoms of scab on pomegranate trees

On the leaves

• Brown or black lesions: These dark spots appear irregularly, causing weakening of the foliage.
• Premature leaf drop: Severe infection leads to defoliation, which reduces photosynthesis and weakens the tree.

On fruits

• Spots and deformations: Affected fruits have lesions that can develop into cracks, compromising their appearance and quality.
• Unmarketable appearance: These altered fruits become difficult to sell.

On the branches

• Dark spots: Infections appear as brownish areas that hinder the development of branches.

Conditions that favor scab

• High humidity: Rainy periods or heavy dew create an environment conducive to the development of the fungus.
• Poor air circulation: Dense foliage or poorly pruned branches promote humid microclimates.
• Infected plant debris: Spores develop on dead leaves, fallen fruit or infected twigs, and can reinfect the plant.

Prevention of scab on pomegranates

Size and pruning

Prune regularly to aerate the tree and reduce moisture in the foliage.

Plant debris management

Collect and dispose of dead leaves or infected fruit in the fall to reduce sources of spores. This debris should be composted away from the orchard or burned.

Choice of resistant varieties

Favor scab-tolerant varieties, especially in areas with high humidity risk.

Moderate fertilization

Limit excessive nitrogen inputs to avoid dense foliage susceptible to infections.

Treatments in organic farming

1. Cultivation methods

• Debris collection: Remove fallen fruit and infected leaves.
• Regular pruning: Improve ventilation within the tree.

2. Biocontrol products

• Sodium bicarbonate: Applied as a curative (3-10 g/l), it inhibits the development of the fungus.
• Talc: As a preventative (13-21 g/l), it prevents spores from germinating.
• Willow bark infusion: Strengthens the natural defenses of plants.
• Horsetail decoction: Helps strengthen leaf and fruit tissues.

3. Stimulators of natural defenses

• Plant purines: Nettle or horsetail purines stimulate the plants' defense mechanisms.
• Alternating treatments: Alternate applications to avoid the development of resistance.

Treatments in conventional agriculture

Copper-based products

• Bordeaux mixture: Applied at different key stages (before leaf fall, before bud swelling, and before flowering), it is effective as a preventative measure.
• Copper Hydroxide: Blocks early infections.

Curative products

Sodium bicarbonate: Used to slow the progression of the fungus.

Cultivation methods

• Destruction of infected debris: Reduce the number of spores present in the orchard.
• Thinning branches: Improve ventilation to reduce humidity that favors the fungus.

Impact of scab on pomegranate crops

Although scab does not always cause major damage, it can reduce fruit quality and increase sorting costs for growers. This disease directly affects the market value of pomegranates and harms the competitiveness of farms.

Grenadiverse: Your solution to bounce back from scab

• Professional quality pomegranate plants: Produced by specialist nurseries, our plants guarantee excellent recovery and resistance.
• Wide choice of varieties: Bare roots, in pots, high stem or half-stem, our plants meet all your needs.
• Fast and careful delivery: Order and receive your plants in less than 15 days.
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Order now from Grenadiverse and benefit from a turnkey offer to revive your crops after a scab attack.

FAQs

• What are the first signs of scab on pomegranate trees? Early symptoms include brown or black spots on the leaves and fruit, often accompanied by cracks on the fruit.
• How can scab be prevented in organic farming? By using cultural methods such as removing debris, aerating the foliage, and applying natural products such as baking soda or horsetail decoction.
• Are copper-based products effective? Yes, Bordeaux mixture and copper hydroxide are particularly effective for prevention.
• What factors promote scab? High humidity, poor air circulation, and the presence of infected plant debris.
• Can overfertilization worsen scab? Yes, excess nitrogen promotes dense foliage and increases humidity, conditions conducive to disease development.
• Does Grenadiverse offer scab-resistant plants? Yes, we offer adapted and resistant varieties, ideal for areas at risk.

Preserve Your Grenadiers and Bounce Back with Grenadiverse

Apple scab remains a challenge for growers, but rigorous management combined with organic or conventional treatments can limit its impact. At Grenadiverse, we'll help you revive your orchards with quality plants and comprehensive technical support. Order today and secure the future of your crops.