Rhynchophorus ferrugineus | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Family: | Curculionidae |
Genus: | Rhynchophorus |
Species: | R. ferrugineus |
Binomial name | |
Rhynchophorus ferrugineus | |
Synonyms | |
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The palm weevil Rhynchophorus ferrugineus is one of two species of snout beetle known as the red palm weevil, Asian palm weevil or sago palm weevil. The adult beetles are relatively large, ranging between 2 and 4 centimetres (1 and 1+1⁄2 inches) long, and are usually a rusty red colour—but many colour variants exist and have often been classified as different species (e.g., R. vulneratus ). Weevil larvae can excavate holes in the trunks of palm trees up to 1 metre (3.3 ft) long, thereby weakening and eventually killing the host plant. As a result, the weevil is considered a major pest in palm plantations, including the coconut palm, date palm and oil palm. [2]
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, [3] and in France in 2006. [4] Additional infestations have been located in Malta, Italy (Tuscany, Sicily, Campania, Sardinia, Lazio, Marche, Puglia and Liguria), Croatia and Montenegro. It is also well established throughout most of Portugal, especially in the South. [5] It also has established in Morocco, Tunisia, and other North African countries. [6] The weevil was first reported in the Americas on Curaçao in January 2009 [7] and sighted the same year in Aruba. [8] It was reported in the United States at Laguna Beach, California late in 2010 [9] [10] but this was a misidentification of the closely related species, R. vulneratus , and it did not become established. [11]
Larvae of Rhynchophorus ferrugineus are considered a delicacy in Southeast Asian cuisine. In some regions, however, larvae farming is strictly prohibited to prevent the potential devastation of plantation crops. [12]
Primarily due to the existence of numerous color forms across their ranges, the taxonomy and classification of red palm weevils has undergone a number of changes in understanding and circumscription. As such, the information in the literature should be viewed as a compilation of data which may apply to both species, depending primarily upon the biogeography; accordingly, the vast majority of publications presumably do refer to R. ferrugineus rather than vulneratus, as the former is by far the most widely invasive. The most recent genus-level revision in 1966 [13] recognized two species of red palm weevil, ferrugineus and vulneratus, and for decades these were interpreted as separate taxa. A genetic study in 2004 [14] concluded that vulneratus was not distinct from ferrugineus, and treated them as synonyms, a view that was accepted until 2013, when yet another genetic study [15] came to the opposite conclusion, based on more comprehensive geographic sampling. Accordingly, the "red palm weevil" species that appeared in the US was vulneratus rather than ferrugineus, though the latter is the invading species in all of the other global introductions. [15]
The native range of this species is considered to include Bangladesh, Cambodia, China, India, Japan, Laos, Pakistan, Philippines, Sri Lanka, Taiwan, and Vietnam; records from Indonesia, Malaysia, Myanmar, Singapore, and Thailand largely or exclusively refer to R. vulneratus. [15] R. ferrugineus has now been reported and confirmed from Albania, Algeria, Aruba, Bahrain, Bosnia and Herzegovina, Croatia, Curaçao, Cyprus, Egypt, France (incl. Corsica), Greece, Israel, Italy (incl. Sicily and Sardinia), Jordan, Kuwait, Libya, Malta, Monaco, Montenegro, Morocco, Oman, Palestine, Portugal (incl. Madeira), Qatar, Saudi Arabia, Slovenia, Spain (incl. the Balearic and Canary islands), Syria, Tunisia, Turkey, and United Arab Emirates. Records from Australia, Papua New Guinea, Samoa, the Solomon Islands, and Vanuatu [6] have not been confirmed and are likely to be specimens of R. bilineatus , a closely related species indigenous to the region.
South America
This species of red palm weevil is reported to attack 19 palm species [18] and is the worst such pest in the world. [16] : 245 Although the weevil was first reported on coconut in Southeast Asia, it has gained a foothold on date palm over the last two decades in several Middle Eastern countries, and then expanded its range to Africa and Europe. [18] This expansion has been due to the movement of infested planting material from contaminated to uninfected areas. [3] In the Mediterranean region, the red palm weevil also severely damages Phoenix canariensis . Currently, the pest is reported in almost 15% of the global coconut-growing countries and in nearly 50% of the date palm-growing countries. [19]
All known hosts of R. ferrugineus as compiled from sources by CABI ISC are: Areca catechu , Arenga pinnata , Borassus flabellifer , Brahea armata , B. edulis , Butia capitata , Calamus merrillii , Caryota cumingii , C. maxima , C. urens , Chamaerops humilis , Cocos nucifera , Corypha umbraculifera , C. utan , Elaeis guineensis , Howea forsteriana , Jubaea chilensis , Livistona chinensis , L. decora , Metroxylon sagu , Phoenix canariensis , P. dactylifera (date palm), P. sylvestris , Roystonea regia , Sabal palmetto , Trachycarpus fortunei , Washingtonia filifera , and W. robusta . [20] [21] Lab studies have reared the insect on diets of Agave americana and Saccharum officinarum , but these findings have not been observed in the wild. There is evidence that the weevil prefers the 'Sukkary' cultivar of date palm to other cultivars. [22]
The palm species W. filifera and Chamaerops humilis may be moderately resistant to the red palm weevil, though both are known hosts. [23]
This weevil usually infests palms younger than twenty years. [24] 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 of trees. 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. [24] The egg hatches into a white, legless larva. The larva will feed on the soft fibres and terminal buds, tunneling through the internal tissue of the tree for about a month. The larvae can occasionally grow to a length of 6 to 7 centimetres (2+1⁄2 to 3 in). [13] 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 3–4 months. [25]
After fertilization, the adult female can lay between 300 and 500 eggs. They lay in holes they produced while searching for food, or take advantage of the cracks or wounds in a recently cut palm. At oviposition, females bend upward and the tarsi are anchored to the tissue with the spines of the third pair of legs to push the ovipositor into the tough palm tissue. After laying, the female protects and secures the eggs with a secretion that rapidly hardens around the eggs. On average, females produce 210 eggs per clutch, most of which hatch over a period of 3 days. The eggs are white, cylindrical, glossy, oval shaped, and measure 1 to 2.5 millimetres (3⁄64 to 3⁄32 in). The back of these eggs possess special 'gill cover' structures that provide the developing insect with oxygen.[ citation needed ]
The neonate larvae are yellow-white, segmented, legless, and have a chitinous head capsule that is a darker brown than the rest of the body. They have powerful horizontal conical jaws which they use to burrow from the axils of the leaves to the crown, where they feed voraciously. Upon completion of larval development, the larva will sometimes emerge from the trunk of the tree, and build a pupal case of fiber extracted from the galleries inside the palm. The larva will then undergo metamorphosis into an adult. The larva will also weave a pupal case at the base of the palm fronds within the frond itself or at the centre of the base of the plant. [24]
The adult insect is an excellent flier and is able to travel great distances. [26] While they prefer to attack palms that are already infested or weakened by other stresses, they will colonize healthy palms. [27]
R. ferrugineus is predated by Chelisoches morio , infected by a cytoplasmic polyhedrosis virus and Metarhizium pingshaense , and parasitized by Heterorhabditis indicus , Hypoaspis spp., Praecocilenchus ferruginophorus , Scolia erratica , Steinernema carpocapsae , and Steinernema riobravis . [28]
Studies show that this insect is attracted by ethyl acetate, 2-methoxy.4.vinylphenol, gamma-nonanoic lactone, 4SSS-ferrugineol, 50H and 4me-9-5Kt. [29]
The infestation of the pest can result in yellowing and wilting of palms, that may lead to the death of the affected plant. 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. [24] 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. [24]
The main control method is through the application of a systemic insecticide. Insecticide is usually applied through a funnel about 5 centimetres (2 in) above the infested area of the trunk. The red palm weevil can be monitored using pheromone lures 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 bioinsecticides are being developed to attract the weevils to a point source and kill them. Another management technique is to drench the base of palm fronds with the entomopathogenic fungus Metarhizium robertsii (syn. M. anisopliae, Entomophthora anisopliae), or Beauveria bassiana . [30] [31] An Italian company claims to have developed a microwave collar that can be used to sterilize individual trees.[ citation needed ] For early detection, bioacoustic analysis may be implemented by inserting a sensitive microphone into the tree and recording any produced sounds. [32] [33] These sounds are analyzed by digital signal processing and artificial intelligence to decide whether they are generated by palm weevils.
Palms' natural defense against this weevil is understudied. [34] RNA interference (RNAi, a kind of gene silencing) is a recently [update] discovered defense system in many host-pathogen systems. [34] RNAi shows promise as a breeding target when breeding palm for RPW resistance. [34]
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 from infested to uninfested areas is not recommended. [24]
The larval grub is considered a delicacy in Vietnam. [35] In Vietnam, the larvae are usually eaten alive with fish sauce. [36] Other methods of cooking include toasting, frying and steaming. They are eaten with sticky rice and salad or cooked with porridge. The larvae are known in the Vietnamese language as đuông dừa ("coconut beetle-larva"). [35] "Sago worms" reported from other countries (e.g., East Malaysia, New Guinea) refer to different, related species of Rhynchophorus. [37]
The Curculionidae are a family of weevils, commonly called snout beetles or true weevils. They are one of the largest animal families with 6,800 genera and 83,000 species described worldwide. They are the sister group to the family Brentidae.
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus Scolytus, namely the European elm bark beetle S. multistriatus and the large elm bark beetle S. scolytus, which like the American elm bark beetle Hylurgopinus rufipes, transmit Dutch elm disease fungi (Ophiostoma). The mountain pine beetle Dendroctonus ponderosae, southern pine beetle Dendroctonus frontalis, and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips Ips typographus. A tiny bark beetle, the coffee berry borer, Hypothenemus hampei is a major pest on coffee plantations around the world.
Washingtonia filifera, the desert fan palm, California fan palm, or California palm, is a flowering plant in the palm family Arecaceae, native to the far southwestern United States and Baja California, Mexico. Growing to 15–20 m (49–66 ft) tall by 3–6 m (10–20 ft) broad, it is an evergreen monocot with a tree-like growth habit. It has a sturdy, columnar trunk and waxy, fan-shaped (palmate) leaves.
Anthonomus eugenii is known as the pepper weevil. This beetle feeds and lays eggs on plants in the genus Capsicum and a few species in the genus Solanum. A. eugenii is native to Mexico, however, it is an important pest of Capsicum in Florida, Puerto Rico, and Central America.
The red ring disease of coconuts and African oil palms is caused by the nematode Bursaphelenchus cocophilus. It is also identified in literature with an alternative scientific name Rhadinaphelenchus cocophilus. The common name, red ring nematode, is derived from its distinguishing symptom.
The palmetto weevil is an insect native to Florida, but has been found as far as southern Texas to the west and South Carolina to the north. It is the largest weevil in North America and the only kind of palm weevil in the continental United States. It infests palms and is considered a pest. Its main target is the Canary Island date palm, but date palms, sabal palms, saw palmetto, Washingtonia, Pritchardia, royal palms, Latania, coconut palms, Caryota, and Bismarckia are also susceptible. Distressed palm trees are usually attacked, which makes transplanted trees a frequent target. The Palmetto Weevils mate at the base of the palm branches where the females deposit their eggs. The grubs then eat into the palm tree, killing it. After the larvae have turned into adult weevils, the damage can be seen, but by then, it is considered to be too late for the tree. The life cycle from egg to adult for a palmetto weevil is about 84 days. For prevention, it is recommended an appropriate insecticidal crown drench is done twice a year for high value palms.
The palm weevil Rhynchophorus vulneratus is one of two species of snout beetle known as the red palm weevil, Asian palm weevil, or Sago palm weevil. The adult beetles are relatively large, ranging between 2 and 4 centimetres long, and vary from a rusty red colour to almost entirely black; many colour variants exist and have led to considerable confusion with other species. Weevil larvae of these species can excavate holes in the trunk of a palm tree up to 1 metre long, thereby weakening and eventually killing the host plant. As a result, these weevils are considered major pests in palm plantations, including the coconut palm, date palm and oil palm.
Rhynchophorus bilineatus, common name Black Palm Weevil, is a species of beetles belonging to the family Curculionidae.
Rhynchophorus, or common name palm weevils, is a genus of beetles in the weevil family, Curculionidae. Palm weevils are major pests of various trees in the family Arecaceae throughout the tropics including: coconut, Areca catechu, species of the genus Phoenix, and Metroxylon sagu. Two species are invasive pests outside their native ranges, Rhynchophorus ferrugineus and Rhynchophorus palmarum.
The South American palm weevil, Rhynchophorus palmarum, is a species of snout beetle. The adults are relatively large black beetles of approximately one and a half inch in length, and the larvae may grow to two inches in length.
Curculio occidentis, the filbert weevil, is a species of weevil in the genus Curculio. The weevils are considered a pest for many species of oak tree due to the damage they cause to acorns.
Curculio elephas is a species of beetle in the family Curculionidae, the true weevils. It is known commonly as the chestnut weevil. It is a serious pest of chestnut in Europe.
Anchylorhynchus is a genus of weevils belonging the family Curculionidae and subfamily Curculioninae. It currently includes 25 described species distributed from Panama to Argentina. Members of the genus are pollinators of palms in the genera Syagrus, Oenocarpus and Butia, with adults living in inflorescences and larvae feeding on developing fruits. The first instar larvae of Anchylorhynchus have an unusual morphology, being specialized on killing other larvae infesting the palm fruits.
Hypera postica, commonly known as the alfalfa weevil, is a species of beetle in the superfamily Curculionoidea; it can be found in alfalfa fields throughout Europe. Considered a destructive threat to alfalfa production in North America, several accidental introductions have been successfully countered though the use of a variety of biological control species.
Sitona lineatus, commonly known as the pea leaf weevil is a species of weevil with a Palearctic distribution. It is a common pest of beans, peas, and other plants in the family Fabaceae. Adult beetles of S. lineatus measure 3.4-5.3 mm in length. They are characterized by a series of colored scales arranged in alternating lines (striae) on the elytra; it is from this characteristic where the species gets its name lineatus meaning 'lined' or 'striped'. The head and pronotum also have fine pointed setae amongst the scales. The antennae are clubbed, pointed and preceded by 7 segments. The femora is dark, but tibiae and tarsi are red. As a member of Order Coleoptera (beetles) their forewings are modified to form hardened covers over the thorax and abdomen, with the hindwings for flight underneath.
Curculio sayi, the small or lesser chestnut weevil, is a species of true weevil in the family of beetles known as Curculionidae.
Listronotus oregonensis, the carrot weevil, is a species of weevil in the beetle family Curculionidae. It is found in North America.
Diocalandra frumenti, commonly known as the palm weevil borer, the lesser coconut weevil, or four-spotted coconut weevil, is a species of weevil in the family Curculionidae. It occurs in Africa, Southern Asia and Northern Australia, and is a pest of coconut and other palm trees.
Odoiporus longicollis, commonly known as banana stem weevil or banana pseudostem borer, is a species of weevil found in South Asia and South East Asia.
Mojojoy is the name of larvae of different palm weevils found in the Amazon region of Colombia, eaten as food and are known as a pest for various palm species. In Peru, it is known as suri or cocotero. The flavor has had different descriptions including resembling the taste of hazelnut or butter. It is also considered a sustainable food source.
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