Apple Blossom Weevil: Identify and Combat this Orchard Pest

The apple blossom weevil ( Anthonomus pomorum ) is a major pest of apple trees, capable of causing significant losses in orchards. Primarily present during flowering, this beetle directly damages flower buds, compromising fruit set. This article examines the symptoms, the life cycle of the insect, as well as biological and conventional control methods to limit its damage.

Symptoms of a Boar Weevil Infestation

An infestation of weevil is particularly visible in spring and manifests itself by:

• Bud piercing: Adults emerging from diapause feed by piercing buds to reach the reproductive organs.
• Brown and dry flowers: The larvae consume the petals and floral organs, preventing fruit formation.
• Premature bud drop: In cases of heavy infestation, a large proportion of flower buds may fall before fruit set.

These symptoms usually appear between March and May, depending on local weather conditions.

Life Cycle of the Weevil

The life cycle of the weevil follows the seasons and temperature variations:

• Emerging from diapause (February-April): Adults emerge from their winter shelter (bark or dead leaves) when the temperature reaches around 9°C.
• Laying (stages B2 to C2): Females lay one egg per flower bud after mating.
• Larvae (April-May): The larvae hatch in 4 to 12 days and feed on the flowers for three weeks.
• Pupation (May): The larvae transform into adults inside the flower buds.
• Summer diapause (June-March): After consuming leaves for about two weeks, adults take refuge under the bark to hibernate.

The end of winter is a key period for monitoring populations and planning interventions.

Means of Prevention

1. Regular Monitoring

• White sticky plate traps: These traps allow you to monitor adults as soon as they emerge from diapause. Place one per hectare before flowering.
• Counting attacked buds: Assess the damage after fruit set to anticipate the risk of infestation the following year.

2. Varietal Choice

• Choose robust varieties that are suited to your terroir and known to be less susceptible to the weevil.

3. Cultural Practices

• Residue Disposal: Destroy dead leaves and fallen bark to reduce winter shelter.
• Reasonable pruning: A well-maintained canopy facilitates access for auxiliaries to infested areas.

Biological Control of the Weevil

1. Natural Predators

Promoting biodiversity in the orchard helps reduce weevil populations:

• Insectivorous birds (tits): Install nest boxes to attract these efficient predators.
• Pathogenic fungi (Beauveria bassiana): These microorganisms attack and eliminate adults and larvae.

2. Striking Technique

This traditional method involves hitting the branches with a stick to make the weevils fall onto a white tarpaulin.

• Advantages: Environmentally friendly and economical, it is ideal for small orchards.
• Limitations: Not suitable for large farms or in cases of massive infestation.

Conventional Control: Products and Techniques

1. Active Substances under Exemption

• Success 4 (Spinosad): This temporarily approved product is particularly effective against adults.
• Pyrevert (Natural Pyrethrum): Use when the temperature exceeds 15°C for optimal impact.

2. Comparison of Methods

• Spinosad offers superior efficacy but its use is limited.
• Natural Pyrethrum performs well in hot weather, but requires careful application.
• Other options such as black soap or neem have moderate effectiveness and require repeated applications.

Precautions:

• Avoid treatments during flowering to protect pollinators.
• Respect re-entry deadlines and follow approved doses.

Economic Impact and Importance of Preventive Management

• Yield losses: Up to 80% of flower buds can be destroyed, directly impacting production.
• Increased costs: Repeated interventions and replacement of weakened trees increase expenses.
• Fruit quality: Attacks weaken trees, reducing their ability to produce quality fruit in the long term.

Arboriverse: Your Partner to Revive Your Orchards

Why Choose Arboriverse?

• Wide range of fruit trees: Half-stem, high-stem, bare-root or potted, adapted to your specific needs.
• Professional quality: Trees produced by specialized nurseries to ensure optimal recovery.
• Direct producer prices: Replace your plants at competitive prices.
• Delivery to your plot: Fast and reliable service, available throughout France.

Our Services

• Orchard design: Personalized support to select varieties suited to your terroir.
• Free quote: Response within 48 hours with a tailor-made offer.
• Technical Support: Dedicated assistance to maximize the success of your planting.

FAQs

• When should you take action against the weevil? Take action as soon as the weevil emerges from diapause (February-March) with traps or targeted treatments.
• What are the early signs of infestation? Look for perforated buds in the pre-flowering stage.
• Is biological control sufficient? It is effective as a preventative measure, but in cases of severe infestation, supplementation with approved products is recommended.
• Does beating work for large farms? No, this method is more suitable for small orchards.
• What products are available in organic farming? Spinosad and natural Pyrethrum, subject to exemption, can be used occasionally.

Conclusion: Acting Together to Protect Your Orchards

Controlling the weevil requires an approach that combines prevention, active monitoring, and rapid intervention. With Arboriverse, benefit from professional support and quality fruit plants to revive your orchards. Contact us today for advice and ensure the sustainability of your operation.