The Red Palm Weevil Rhynchophorus ferrugineus is an invasive exotic species and phytosanitary quarantine species which is present in Spain since 1995, when it was detected in Granada and Malaga.This insect, originally from the tropical regions of Asia and Polynesia, has extended continuously through other areas of the planet, colonising different species of palm trees.
Currently, it is one of the main pests that affect palm trees in the Middle East and North Africa. From these areas, through traditional palm tree exporters to Europe, is where the insect has been introduced onto the Iberian Peninsula.The existence of important palm groves in the Iberian East makes it necessary to pay special attention to this insect.
AFFECTED SPECIES OF PALM TREES
The insect colonises a large number of species of palm tree. In the countries of origin it is referenced in Coconut Palms (Cocos nucifera) and Guinea Palm trees (Elaeis guineensis) amongst many others. Nevertheless, in Spain it stands out mainly because of its attacks on the Canary Palm tree (Phoenix canariensis) and the Date Palm (Phoenix dactylifera), which is the most representative of our palm trees. It also affects the Washingtonia Palm (Washingtonia spp).
MORPHOLOGY AND BIOLOGY
Rhynchophorus ferrugineus is a coleopteron belonging to the Curculionidae family.
Adult: Its size is quite big, reaching between 2 and 5 cm long. The insects of this family are characterised for having an extended head in the shape of a beak (“face”), where the antennae are positioned in the shape of a reddish mace.
The pre-thorax shows some very visible black stains of variable size and shape. Along the elytrons the linear markings are emphasised, also in black.
The males are differentiated from the females by a “comb”, thick and few hairs on the end of the beak.
Egg: It is oval-shaped. The egg-laying is done individually on the soft tissue of the palm tree’s crown. It measures between 1 and 2.5 mm long. On average, the females lay between 300 and 400 eggs.
Larva: It develops on the inside of the palm tree’s living tissues, until reaching between 3 and 5 cm in size. At the beginning it has a creamy white colour that in the last stage acquires a darker tone. It is clearly apodous (with no legs). Its general aspect is pear-shaped, which gives it a chubby look. The head, which is brown, has very powerful jaws that allow it to perforate the vegetable tissues of its host.
Pupa: It is found mainly at the base of palm trees, surrounded by a good sized oval cocoon (4 to 6 cm long), and made by the larva with fibres from the same palm tree. In which case, it is not easy to detect the insect if the area where it has inserted itself is not opened.
Its capacity for reproduction is very important. In Spain the complete cycle, from egg to adult, has a duration of three and four months.
The adults do not tend to abandon the palm tree where they have developed, until it is practically destroyed. So, there can be various generations inside the same specimen, where at any given moment all the phases/stages of the plague can be found.
The adults have a very high ability for flying, which allows them a great capacity for the dispersion and colonisation of new palm trees. They seem to show a preference for hurt or weak palm trees. Once the first adults arrive at a suitable palm tree, the males generate an aggregation pheromone that attracts many red palm weevils of both sexes.
The females deposit their eggs in holes made with their face (or beak), in wounds made during the harvest, pruning and desuckering.
SYMPTOMS AND DAMAGES IN THE CANARIAN PALM TREE
The most common symptom that may suspect an insect attack is the withered look of the leaves at the centre of the crown, which can eventually dry up and remain hanging on the ground.
In very severe attacks the crown of the tree ends up drying and causes the death of the palm tree. By pulling down the affected outer leaves, they fall off with ease. In the leaf base, galleries of larvae can be observed and frequently the pupae cocoons.
On opening the crown of a palm tree with an advanced degree of infection, there are plenty of larvae of various sizes in a mass of fermenting tissue that gives off an unpleasant and peculiar smell.
The affected palm tree dies in the short term due to the meristem or palm heart being totally destroyed, with its interior in decomposition.
Life cycle: Eggs: less than 1 week. Larva: approximately 4 to 6 weeks. Pupa: approximately 2 or 3 weeks. Adults: approximately 12 to 16 weeks.
Source: Leaflet «Curculiónido Ferruginoso o Picudo Rojo de las Palmeras», published by the Conselleria d´Agricultura, Pesca i Alimentació of the Generalitat Valenciana.
THE RHYNCHONEX® SYSTEM
The Rhynchonex® system consists of using traps, pheromones and kairomones for the detection and monitoring of the Red Palm Weevil: Rhynchophorous ferrugineus.
Scientific investigation has demonstrated that the weevils find the host palm trees through the sense of sight and smell.
RHYNCHONEX® ATTRACTION STRATEGIES
- Olfactory strategy: It is achieved through an aggregation pheromone diffuser and a kairomone diffuser, acting synergistically.
- Food strategy: It is carried out through food attractant inside the trap, together with water, since Rhynchophorus ferrugineus needs a humid environment.
- Visual strategy: Various investigations have shown that red traps attract more.
- Decoy strategy: It is achieved through a decoy, consisting of a red plastic weevil, greater than the actual size of the insect, in order to increase the attraction power of the trap.
- Accessibility strategy: It is achieved through a yellow-rhomboidal plastic mesh, which allows the weevils to be able to hold on to the trap. This special mesh that surrounds the trap serves as a platform for the landing of the beetles. In this way, the Rhynchophorus ferrugineus can enter the holes of the trap climbing as they like to do when they go to the palm trees to feed on them.
DETECTION AND MONITORING
We will use 1 to 3 RHYNCHONEX® traps per hectare (at least 1 per plot), placed preferably buried in the ground. In case of not being able to bury the trap, the CROSSTRAP® MINI trap is recommended.
The traps should be placed 50 to 100 meters from each other, and throughout the year, especially in spring, summer and autumn, as the activity of the pest increases with temperature. The placement of a greater number of traps per surface will significantly reduce new infestations.
For exhaustive monitoring the number of traps per surface area is increased, according to the location and uniformity of the plots: approximately 1 RHYNCHONEX® or CROSSTRAP® MINI trap every 50 metres. This translates into a density of 4 to 6 RHYNCHONEX® or CROSSTRAP® MINI traps per hectare.
Using traps with pheromones and kairomones, the Rhynchophorus ferrugineus females and males are captured, in a proportion of 2/3 females and 1/3 males. By capturing both adult males and females, mating is reduced.
The females that are captured tend to already be fecundated. Therefore, capturing these females is very effective in reducing the egg-laying on the palm trees. Each insect captured is an insect less on the palm tree.
FACTORS THAT INFLUENCE IN THE NUMBER OF TRAPS NEEDED
To decide the number of traps, we must take into account the population of the pest, the bordering plantations, the level of control that is intended, etc.
An important factor is the size of the plantations. In small and irregular plantations, a higher relative density of traps is required than in larger and uniform surface plots.
Another important factor is the distance of some plots with others that have the same pest. In these cases, it is necessary to reinforce the boundaries of the plots, so it may be necessary to increase the density of traps per hectare.
RHYNCHONEX® or CROSSTRAP® MINI traps.
The RHYNCHONEX® traps are humid traps that are used together with pheromones and kairomones, for the detection and monitoring of the Red Palm Weevil Rhynchophorus ferrugineus.
They are made of a plastic polymer that does not emit odours when heated by the effect of the sun, and they support ultraviolet rays, with a half-life of 6 to 7 years.
They are made up of three easily adjustable parts, a base, a lid and a special hanger to hang the RHYNCHONEX® ATTRACTANTS KIT 90 DAYS diffuser.
The traps include a rhombus-shaped plastic mesh, which is especially designed to simulate the roughness of the trunk of the palm tree. This makes it easier for the Red Palm weevils to enter into the trap.
The RHYNCHONEX® 17 trap has a volume of 17 litres. The frusto conical shape of the base of the trap is red and has 4 perpendicular holes with measurements of 3 x 7 cm, so the insects can enter in easily. The lid is also red and has 4 entrance holes with 3 x 7 cm measurements.
The RHYNCHONEX® 7.5 trap has the same characteristics as the RHYNCHONEX® 17 trap, but with a volume of 7.5 liters. The lid has 2 entrance holes with 3 x 7 cm measurements.
They are wet traps, so they should be filled with water up to 2/3 of their volume.
PLACEMENT AND HANDLING:
Traps should be placed half-buried to the entrance holes, and preferably in the shade, since they retain humidity for longer.
Using the wet RHYNCHONEX® traps, the red date palm weevill dies by drowning in the water.
It is recommended to cover the traps a little bit with palm tree leaves, to increase humidity and avoid excessive evaporation.
In case of not being able to use buried RHYNCHONEX® traps (being in areas where they can be manipulated by unauthorized persons, or should be out of the reach of children in public parks and gardens) it is recommended to use the CROSSTRAP® MINI traps.
In the natural environment, it is recommended to use only the CROSSTRAP® MINI trap, due to its high specificity.
The combination of food and pheromones increases the efficiency of the system: dates, sugar cane, apples and bananas are foods that can be used in the RHYNCHONEX® trap.
RHYNCHONEX® DECOY (Code: TA180)
This is a plastic red palm beetle. It is 5 cm in size and is placed on the outside of the RHYNCHONEX® trap and used as bait, complementing the signal emitted by the attractants.
The congeners -especially the females- are attracted by this stimulus, which is complemented by the signal emitted by the attractants placed inside the trap.
CROSSTRAP® MINI traps
For trapping in the natural environment or if you are not able to use the buried RHYNCHONEX® trap, it is recommended to use the CROSSTRAP® MINI WITH DRY COLLECTION CUP trap (Code: TA204).
The CROSSTRAP® MINI WITH DRY COLLECTION CUP trap is a suspended trap that captures insects in flight and is very effective from spring to autumn. The design and the slippery coatings of the trap stop the captured insects from escaping. The trap does not require any type of liquid and does not need a food attractant. The insects die on the inside of the collection cup through dehydration, which makes handling it easier. The traps can be hanged from natural or artificial supports, but always at a sufficient distance away from the palm trees.
The trap consists of a polypropylene lid, 33 cm in diameter with a central carabiner attached to a steel spring. Two reinforced PVC sheets are held in place by four steel springs in the lid’s upper section, serving as shock absorbers against strong winds. This helps to avoid damage to the trap. In the lower section, the reinforced PVC sheets are held in place by a polypropylene funnel, 30 cm in diameter and four steel springs. The collection cup for the captured insects is in the lower section of the funnel and is attached by metal screws.
The PVC sheets, funnel and collection cup are treated with a slippery film to significantly increase captures and prevent the pests from escaping.
The unfolded trap measures 33 cm in diameter and 146 cm in height. Once folded the trap measures 33 cm in diameter and 40 cm in height.
The trap can last up to 7 years due to its highly resistant components.
PLACEMENT AND HANDLING:
The traps should be suspended horizontally with a rope in-between two trees or from one of the branches, taking care that the trap does not come into contact with the tree trunk.
In this way, the trap does not knock against the tree and break, therefore ensuring that the insects are able to distinguish the trap from the tree trunk and go to the trap. Keep them at least 5 meters away from the palm trees. It is best to install them in areas without palm trees.
The trap is activated by placing the attractants diffuser RHYNCHONEX® ATTRACTANTS KIT 90 DAYS hung in the holes of one of the PVC sheets with the clips provided.
The height of the installed trap is not of importance, as long as the collection cup does not touch the ground or any other object. A metal support designed specifically for this purpose is also available: ECONEX CROSSTRAP® SUPPORT (Code: TA147).
The trap is used with the CROSSTRAP® DRY COLLECTION CUP (Code: TA157) for dry use or live captures. The dry collection cup has approximately a 2-litre capacity (12,5 cm diameter x 19 cm height) and is supplied with a stainless-steel mesh that drains away rainwater 100% and provides excellent air circulation for dry (live) captures.
Attractants diffuser RHYNCHONEX® ATTRACTANTS KIT 90 DAYS (Code: VA263)
Kit consisting of a RHYNCHONEX® PHEROMONE 90 DAYS diffuser and a RHYNCHONEX® KAIROMONE 90 DAYS diffuser, in the same blister, for Rhynchophorus ferrugineus, with a duration of 90 days and an identification label to place on the traps with the date of placement and replacement of the kit. It is sold in boxes of 6 units.
RHYNCHONEX® PHEROMONE 90 DAYS: Is a pheromone diffuser of Rhynchophorus ferrugineus with a mixture of 4-methyl-5-nonanol and 4-methyl-nonanone. It has a duration of 90 days in field conditions.
RHYNCHONEX® KAIROMONE 90 DAYS: Is a kairomone diffuser of Rhynchophorus ferrugineus made up of ethyl acetate. It has a duration of 90 days in field conditions.
Scientific research has shown that the synergistic action of pheromone and kairomone acting together increases significantly the number of catches, increasing them by 2.5 to 5 times.
The kit should be stored in its original packaging and it is recommended to keep it in the fridge at 4 oC in which case it can last up to 2 years.
ADVICE ON PLACING THE TRAPS
- It is recommended to space the traps 50 to 100 m apart.
- The RHYNCHONEX® traps that are placed in the shade retain the humidity for longer. The CROSSTRAP® MINI traps can be installed in both shady areas and sunny areas, preferably outside the plots.
- Regular check-ups of the palm trees in affected areas.
- In palm trees where an infestation of Red Palm Weevil is suspected or detected, one must proceed rapidly to its sanitation and protection through an authorised phytosanitary treatment.
- All the dead palm trees and damaged tissues must be destroyed, in accordance with the regulations.
- When pruning in spring and summer, an authorised phytosanitary treatment must be used after pruning. Only prune during winter preferably, as it is the period the pest has the least activity. The remains of the pruned trees should always be shredded, cut into pieces or burnt.
- Clean the crown of the palm tree of leaves to allow regular inspection.
- It is important not to plane down or shave the tree trunk, as it encourages infestations.
- The palm trees affected with illnesses, such as putrefaction of the leaves and shoots are more prone to an infestation by the Red Palm Weevil. Therefore, they should be treated with a fungicide and an insecticide, as it is essential to stop the Weevils from depositing their eggs in these areas.
- Within an eradication strategy or integrated control measure, capturing the Red Palm Weevil adults with the RHYNCHONEX® SYSTEM is fundamental.
- Dedicate time to training, to get to know well the biology and ecology of the insect, as well as, the RHYNCHONEX® SYSTEM for the detection and monitoring of Rhynchophorus ferrugineus.
Application of an integrated control strategy for the Red Palm Weevil (Rhynchophorus ferrugineus).
Susi Gómez Vives, Michel Ferry (Phoenix Station): Research Centre for the palm tree and agriculture in Oasis – Elche (Spain).
Orthophotos of Finca El Batatal and adjacent properties.
- Susi Gómez Vives, Michel Ferry (Phoenix Station): Research Centre for the palm tree and agriculture in Oasis – Elche (Spain).
- Orthophotos of Finca El Batatal and adjacent properties.
Orthophotos of Finca la Concepción.
- Situation at the beginning of applying the strategy, in March 2007.
- Situation in January 2009. In green the palm trees have no symptoms, in yellow the palm trees have symptoms and in red the palm trees are removed.
- The increasing number of newly infested palm trees by the Red Palm Weevil on the Mediterranean coast, despite great efforts carried out by the Plant Health Authorities with regard to the elimination of infested specimens and foliar treatments, shows that it is not possible to control this pest with only one type of treatment or intervention. It is necessary the application of a well-defined and programmed integrated control strategy.
- The application of an integrated control strategy not only allows the infected palm trees to recuperate, but also to prevent the dispersal of the pest.
- This integrated control strategy is based on regular inspections carried out on palm trees, the installation of a network of traps for exhaustive monitoring, the implementation of mechanical or chemical sanitation for infested palm trees and preventive treatments for all the palm trees in the area.
RHYNCHONEX® ATTRACTANTS KIT 90 DAYS
Corrugated cardboard box with 120 units (20 packs of 6 units).
Measurements of the box: 0.40×0.60×0.35 m (width x length x height).
Weight of the box: 9,40 kg.
Number of boxes per pallet: 20.
Measurements of the pallet: 0.80×1.20×1.90 m (width x length x height).
Weight of the pallet: 195 kg.
ECONEX CATALOGUE OF PRODUCTS AND SERVICES FOR FOREST PESTS
Catalogue in PDF format with an extension of 94 pages. It is an essential reference work for finding out about the biological behaviour of the main species of forest insects and the solutions of ECONEX to give an effective answer to the problems generated by these through the use of traps and specific attractants.
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TRIPTYCH RHYNCHONEX® SYSTEM
Triptych in PDF format that can be downloaded by clicking on the image.
ECONEX WEB RESOURCES
ECONEX corporate website section that allows you to access online information on ECONEX solutions for the biocontrol of other especially relevant agricultural and forestry pests.
To access the ECONEX WEB RESOURCES click on the image.