The Red Palm Weevil

Introduction

The Red Palm Weevil or curculionido ferruginoso (Rhynchophorus ferrugineus Olivier) is a weevil originating from the tropical regions of Asia and Polynesia that has been continuously spreading throughout other subtropical and temperate regions and colonising different species of palm trees. It is one of the main infestations affecting the palms of the Far East, the Middle East and North Africa. It was introduced into Spain at the time of grand scale importation of Phoenix dactylifera from Egypt. First detected in 1995 in Almunecar (Granada), the disease has since spread all along the coastal fringe of the Mediterranean and through the Canary Islands, where it is devastating great numbers of palms.

In Spain it primarily attacks the Canary Palm (Phoenix canariensis) followed by the Date Palm (Phoenix dactylifera).

Informations

At present, the following palm tree species could be infected by the attacked: Areca catechu, Arenga pinnata, Borassus flabellifer, Butia capitata, Calamos merillii, Caryota maxima, C. cumingii, Cocos nucifera, Corypha gebanga, C. elata, Elaeis guineensis, Livistona decipiens, Metroxylon sagu, Roystonea regia, Ph. theophrasti, Ph. sylvestris, Sabal umbraculifera, Trachycarpus fortunei, Whashingtonia robusta y W. filifera.

BIOLOGY
Insects of this family are characterised by a beak shaped prolongation of the head, by distinctly elbowed antennae, and by their very characteristic reddish colourisation (ferruginoso). The male differs from the female by having a brush like structure on its ‘beak’.
The adults can fly long distances and climb well; they are easily able to climb from the ground to the crown of palm trees.
The female lays her eggs both in the insulated cavities of purposely made wounds at the base of the leaves and in the soft tissue inside leaf buds at the top of the trunk near the start of the leaves (the crown of the palm); it is therefore difficult to spot them.

The larva grows inside the humid soft fibres of the palm, on which it also feeds. It is between 3 and 5 cm long, legless and of squat aspect. Its head is a ruddy brown colour. These larvae can excavate cavities of more than a metre in length.
The Pupa is found at the base of the palms, both inside and outside the trunk, protected

In the Spanish Mediterranean region/ Islas Baleares, the complete life cycle from egg to adult takes between three and four months which means up to four generations a year.
The adults colonise the palms as they fly between them. They prefer diseased trees that have pruning wounds or are weak from recent transplantation.

SYMPTOMS
Young centre leaves with leaflets that have been eaten producing serrated edges and are drooping and/or sickly looking. In the more advanced stages of infestation the crown breaks and is felled by the wind. Really bad attacks cause the crown to dry up and bring about the death of the tree. When the affected leaves are shed, and they fall quite readily, the open cavities at the base, made by the larvae in their last stage of development, can be observed. The pupal cocoons give off a characteristic acidic odour.

METHODS OF CONTROL AND PREVENTION
Given the characteristics and dangerous nature of the infestation it is vital that it is rapidly detected. To get a reliable diagnosis of the condition of a palm, a specialist company or professional, qualified and able to advise on treatments or methods of prevention should be consulted.
Pheromone traps are a very effective biological method of reducing the weevil population.
Also Palm-Life Biological spray kill the larves and is a very effective way to save your palm-trees.(biological, Palm-Life).