The red palm weevil, Rhynchophorus ferrugineus, is a species of beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

 also known as the Asian palm weevil or sago palm weevil. It is relatively large, between two and five centimeters long; usually a rusty red colour, but many colour variants exist and have been often been named as different species (e.g., Rhynchophorus vulneratus;). Its larvae can excavate holes up to a metre long in the trunk of palm trees, thereby weakening and eventually killing the host plant. As a result, the beetle is considered a major pest of palm plantations, including the coconut palm, date palm

Date Palm

The date palm is a palm in the genus Phoenix, cultivated for its edible sweet fruit. Although its place of origin is unknown because of long cultivation, it probably originated from lands around the Persian Gulf. It is a medium-sized plant, 15–25 m tall, growing singly or forming a clump with...

 and oil palm

Oil palm

The oil palms comprise two species of the Arecaceae, or palm family. They are used in commercial agriculture in the production of palm oil. The African Oil Palm Elaeis guineensis is native to West Africa, occurring between Angola and Gambia, while the American Oil Palm Elaeis oleifera is native to...

. Originally from tropical Asia, the red palm weevil has spread to Africa and Europe, reaching the Mediterranean in the 1980s. It was first recorded in Spain in 1994, and in France in 2006. The weevil was first reported in the Americas on Curaçao

Curaçao

Curaçao is an island in the southern Caribbean Sea, off the Venezuelan coast. The Country of Curaçao , which includes the main island plus the small, uninhabited island of Klein Curaçao , is a constituent country of the Kingdom of the Netherlands...

 in January 2009 and sighted the same year in Aruba. It was reported in the United States at Laguna Beach, CA

Laguna Beach, California

Laguna Beach is a seaside resort city and artist community located in southern Orange County, California, United States, approximately southwest of the county seat of Santa Ana...

 late in 2010.

Life Cycle

This weevil usually infests palms younger than twelve years. While the adult causes some damage through feeding, it is the burrowing of the larva into the heart of the palm that can cause the greatest mortality. The adult female lays approximately two hundred eggs on new growth in the crown of the palm, at the base of young leaves, or in open lesions on the plant. The egg hatches into a white legless larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

. The larva will feed on the soft fibres and terminal buds, tunnelling through the internal tissue of the tree for about a month. The larvae can occasionally grow to a length of six to seven inches. At pupation, the larva will leave the tree and form a cocoon built of dry palm fibers in leaf litter at the base of the tree. The total life cycle takes about 7–10 weeks.

Symptoms of infestation

The crown wilts first, and lower leaves will follow, due to damage to vascular tissue. Major symptoms such as crown loss or leaf wilt are usually only visible long after the palm has become infested. Secondary infections of opportunistic bacteria and fungi may occur within damaged tissues, accelerating decline. By the time these external symptoms are observed, the damage is usually sufficient to kill the tree, and the infestation may have been present for six months or longer. In high-density infestations, sounds of the larvae burrowing and chewing can be heard by placing one's ear to the trunk of the palm. Recent research has been conducted using electronic listening devices or dogs trained to recognize the scent of weevils or palm decay to detect infestations at low densities earlier in the process.

Control

The main control method is through the application of a systemic insecticide. Insecticide is usually applied through a funnel about 5 cm above the infested area of the trunk.The red palm weevil can be monitored using pheromone lures bucket or pitfall traps, and alternative forms of control use field sanitation and mass trapping with traps baited with pheromone and plant derived semiochemicals. New alternative technologies using semiochemicals and bio insecticides are being developed to more effectively control this devastating pest of palm trees. One of them is a new formulation with insecticide and pheromone called SPLAT RPW that attracts the weevils to a point source and kills them. Another ecofriendly management technique is to drench the base of palm fronds with the entomopathogenic fungus Metarhizium anisopliae

Metarhizium anisopliae

Metarhizium anisopliae, formerly known as Entomophthora anisopliae , is a fungus that grows naturally in soils throughout the world and causes disease in various insects by acting as a parasite. Ilya I. Mechnikov named it after the insect species it was originally isolated from: the beetle...

, or Beauveria bassiana

Beauveria bassiana

Beauveria bassiana is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease; it thus belongs to the entomopathogenic fungi. It is being used as a biological insecticide to control a number of pests such as...

.

Prevention

As the weevil prefers to lay its eggs in softer tissues, avoiding mechanical damage to plants can help to reduce infestation. Tarring wounds after pruning a plant of dead or old leaves can also reduce the probability of infestation. The movement of plant material such as husks, dead leaves, or untreated coir

Coir

Coir is a natural fibre extracted from the husk of coconut and used in products such as floor mats, doormats, brushes, mattresses etc. Technically coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. Other uses of brown coir are in upholstery...

 from infested to uninfested areas is not recommended.

Host range

Areca catechu

Areca catechu

Areca catechu is the areca palm or areca nut palm, , a species of palm which grows in much of the tropical Pacific, Asia, and parts of east Africa. The palm is believed to have originated in either Malaysia or the Philippines...

, Arenga pinnata

Arenga pinnata

Arenga pinnata is an economically important feather palm native to tropical Asia, from eastern India east to Malaysia, Indonesia, and the Philippines in the east...

, Borassus flabellifer

Borassus flabellifer

Borassus flabellifer, the Asian Palmyra palm, Toddy palm, Sugar palm, or Cambodian palm, is native to South and Southeast Asia, in the Indomalaya ecozone...

, Caryota maxima, C. cumingii, Cocos nucifera (coconut palm), Corypha gebanga, C. elata, Elaeis guineensis, Livistona decipiens

Livistona decipiens

Livistona decipiens is a species of palm native to the sclerophyll woodlands of Queensland, Australia. The species is now widely cultivated in arid regions worldwide as a decorative plant....

, Metroxylon sagu

Metroxylon sagu

Metroxylon sagu is a species of palm in the genus Metroxylon, native to tropical southeastern Asia in Indonesia , Papua New Guinea, Malaysia and possibly also the Philippines .It is a monocarpic palm growing to 10 m tall or more, with pinnate leaves up to 7 m...

, Oreodoxa regia, Phoenix canariensis, P. dactylifera (date palm), P. sylvestris

Phoenix sylvestris

Phoenix sylvestris also known as Silver Date Palm or Sugar Date Palm, is a species of flowering plant in the palm family native to southern Pakistan,most of India and Bangladesh. Growing in plains and scrubland to 1300 m, the fruit from this palm species is used to make wine and jelly...

, Sabal umbraculifera, Trachycarpus fortunei

Trachycarpus fortunei

Trachycarpus fortunei is a palm native to central China , south to northern Burma. It is a fan palm Trachycarpus fortunei (Chusan Palm, Windmill Palm or Chinese Windmill Palm; syn. Chamaerops fortunei Hook., T. wagnerianus Becc.) is a palm native to central China (Hubei southwards), south to...

, Washingtonia

Washingtonia

Washingtonia is a genus of palms, native to the southwestern United States and northwest Mexico...

spp.. Lab studies have reared the insect on diets of Agave americana and Saccharum officinarum, but these findings have not been observed in the wild.

Habitat range

Bangladesh, Bahrain, Cambodia, China, India, Indonesia, Japan, Kuwait, Laos, Malaysia, Myanmar, Oman, Pakistan, Philippines, Qatar, Saudi Arabia, Sri Lanka, Taiwan, Thailand, United Arab Emirates and Vietnam, also Papua-New Guinea and Solomon Islands. It has most recently been reported in Slovenia, France, Italy, Malta, Greece, Spain, Portugal, Turkey, Cyprus, Syria, Morocco, Aruba and the United States.

See also

• Sago worm
  Sago worm
  The Sago worm or Sago grub is the larva of the Sago Palm Weevil or Red Palm Weevil .-Overview:The worm lives and feeds on the starchy pulp of the trunk of the sago palm , which is common in the wetter freshwater swampy parts of Southeast Asia and Melanesia...
  
  or Sago grub.
• CISR: Red Palm Weevil Information

External links