What kind of damage does the red palm weevil cause to palm trees?

The symptoms of a red palm weevil infestation in palm trees only become visible after a while. Normally, it takes about a year for the effects to make themselves known. When this happens, the red palm weevil larvae will have already dug passages inside the trunk, making it essential that you act fast to try and save the tree – although, at times, it may be too late.

The red palm weevil and the damage it causes to palm trees

The first recorded appearances of the red palm weevil in Europe date back to 1996 in Spain. Just 10 years later, this pest had firmly established itself in palm trees throughout the Mediterranean. When the larvae of the red palm weevil causes damage to palm trees, it only becomes evident after a few months. These symptoms may vary depending on the species of palm tree infested. Here are a few of the most common:

• • Chewed leaves.

• • Drooping central leaves.

• • Declining appearance.

• • Appearance of sawdust.
  • Seeping of fermented sap.
  • Asymmetrical crown.

• • • • 

        • Remains of cocoons.

      

      • Holes at the base of the leaves.

    

    • Eaten or shortened rachis.
    • The presence of chewed leaves on the ground.

  

  • “Mushroom” palm tree (this is the shape the palm tree takes when all of its leaves point towards the ground).

In general, infestations caused by the larvae of Rhynchopohorus ferrugineus, which is the scientific name of this beetle, are only detected after a lot of damage has already been caused. This is why it’s important to check palm trees often and carefully. You should be looking for the following symptoms:

• Holes in the crown or trunk through which fibres are expelled, as well as a brown, viscous liquid.
• The sound of gnawing caused by the larvae eating. You’ll need to get very close to the plant to hear this.
• Old, bent leaves. This gives the tree an umbrella-like appearance.

The best solution available today: endotherapy

At present, endotherapy is the best solution we have to prevent or treat an infestation of this type. The recommended frequency will vary depending on which insecticide is applied, but it should be sufficiently often so as to ensure that the larvae eat the material impregnated with the insecticide and die as soon as possible, avoiding irreversible damage.

This technique has multiple advantages, including:

• It is clean and sustainable.
• It is safe in terms of the environment, occupational health and safety, and the health of the general population.
• It is simple, effective, economical and requires only a small amount of insecticide.
• There’s no need for repeat drilling.
• It is injected by gravity, which avoids causing damage to the inside of the trunk through pressure.
• It is the most highly recommended preventive treatment.

The steps involved are as follows:

1. A hole is drilled in the trunk.
2. The pipettes are inserted.
3. Mastic sealant is applied.
4. The cap is opened and the dose of insecticide inserted.

We recommend applying effective preventive treatments such as endotherapy before you start to see the symptoms of red pam weevil infestation. At SOSPALM, we have extensive experience in these types of interventions.