Curculio nucum

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Nut weevil
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Infraorder: Cucujiformia
Family: Curculionidae
Subfamily: Curculioninae
Genus: Curculio
Species:
C. nucum
Binomial name
Curculio nucum

Curculio nucum, the nut weevil, is a medium-sized beetle, with an especially elongated snout, characteristic of the Curculionini tribe of the weevil family (Curculionidae). Its larvae develop in hazel nuts Corylus avellana, being a serious pest in hazelnut orchards. It occurs in most of Europe, from south Sweden, Finland and Great Britain to the Mediterranean.

Contents

A brown nut-weevil Weevil3.jpg
A brown nut-weevil

Description

This weevil ranges from 6 to 8.5 mm. [1] The female's snout is as long as the rest of the body, with a reddish end. The male snout is about 1/3 shorter. The body cover is usually light brown, similar to the colour of mature hazelnuts. This species is often confused with another commonly occurring weevil of the same genera – the gland weevil, Curculio glandium , which lives on oaks. Despite overall similarity, the weevils differ in some morphological details. Curculio nucum has broader segments of flagellum and the segments are covered with semi-erect hairs which in C. glandium are adpressed. [2] [3]

Differences in antennae features of Curculio glandium (left) and C. nucum Curculio antenae comparison.jpg
Differences in antennae features of Curculio glandium (left) and C. nucum

Curculio glandium is considered as closely related to C. nucum and as C. undulatus, all of which are grouped together in the "glandium clade". C. cameliae from Japan is also related to this group. Other similar species in Europe that live on oaks, such as Curculio pellitus, C. venosus and C. elephas are gathered in the "elephas clade". Species in the elephas clade have convex elytra and a dense vestiture hiding the line of the first ventral segment, whereas the glandium clade weevils have flattened elytra and the first ventral segment clearly visible through the sparse scales. [4] Tribe Curculionini differs from other weevils, and from other Coleoptera, by the unique cone-shaped mandibles that move vertically instead of horizontally. [5]

Life cycle

Development takes place mostly within a two-year life cycle. Adult beetles emerge in the spring from the soil where they have been overwintering as adult. They feed on hazel buds and leaves. The adults can be found from May to the end of August. Females oviposit within maturing hazelnuts, laying a single, yolk-rich egg per nut, around the end of July/beginning of August. One female can lay up to 20-30 eggs. One week after egg deposition the larvae hatch, and start to feed inside a nut. They spend around one month there, eating most of the nut content. By the end of the summer, mature larvae leave the nuts by round holes then burrow into the ground where they build individual cells. After overwintering, most larvae diapause for the whole season and undergo metamorphosis in the next summer. Newly formed adults then mainly overwinter in their pupal cases before emerging in the spring of the following year. Adult females are reproductively immature at emergence and ovarian development is only attained from 1 to 2 months later, after the feeding period. Small numbers of individuals delay metamorphosis spending more than one winter in the soil. This alternative life story of individuals overwintering more than once may confer additional benefits over a single-year life cycle, such as surviving bad conditions (like lack of host objects). On the other hand, it may increase exposure to predators. Moreover, adult overwintering diapause could be energetically more costly than larval diapause, but could in turn allow adults to be better synchronized with their host plants. [6]

Larva of Curculio nucum Hazelnootboorderlarve.jpg
Larva of Curculio nucum

Infestation and control

Inside an infested nut, a cream/white larva with a brown head surrounded by excrement may be found. A hole in a nut shell is a sign that the larvae has already finished feeding, and left the nut, substantially eaten out.

Basic control of this weevil is spraying the orchards with insecticides (containing for example methomyl, thiacloprid, deltamethrin). However, countries producing the greatest crop of nuts, such as Turkey, Italy, France and Spain, are working on alternative methods of control. Some research suggests that it may be possible to use entomopathogenic nematodes such as Heterorhabditis indica. [7] This nematode is deadly to full-grown larvae that inhabit the soil under the tree canopy. The fungus Beauveria bassiana may also be helpful as a control agent. Research in Italy proved that this fungus, if applied into the soil well, kills almost all the larvae. This fungus should be applied when the larvae start to burrow into the soil. [8] According to some investigations, shell thickness is not correlated with the level of weevil damage, but nuts whose shells harden rapidly may be resistant to weevil attack to some extent. [9]

Related Research Articles

<span class="mw-page-title-main">Curculionidae</span> Family of beetles

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.

<i>Beauveria bassiana</i> Species of fungus

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 group of entomopathogenic fungi. It is used as a biological insecticide to control a number of pests, including termites, thrips, whiteflies, aphids and various beetles. Its use in the control of bedbugs and malaria-transmitting mosquitos is under investigation.

<span class="mw-page-title-main">Vine weevil</span> Species of beetle

The black vine weevil is an insect native to Europe but common in North America as well. It is a pest of many garden plants.

<span class="mw-page-title-main">Entomopathogenic fungus</span> Fungus that can act as a parasite of insects

An entomopathogenic fungus is a fungus that can kill or seriously disable insects.

<i>Hylobius abietis</i> Species of beetle

Hylobius abietis or the large pine weevil is a beetle belonging to family Curculionidae. This species is widely regarded as the most important pest of most commercially important coniferous trees in European plantations. Seedlings planted or arising from natural regeneration after clear felling operations are especially at risk. The adult weevils cause damage by eating the bark of seedlings around the 'collar' of the stem, thus 'ring-barking' the tree seedling which usually results in its demise.

<i>Curculio</i> Genus of beetles

Curculio is a genus of weevils belonging the family Curculionidae and subfamily Curculioninae. Members of the genus are commonly referred to as acorn weevils or nut weevils as they infest the seeds of trees such as oaks and hickories. The adult female weevil bores a tiny hole in the immature nut to lay her eggs, which then hatch into legless grubs. In autumn, the grubs bore holes through the shells from the inside to emerge into the soil where they may live for a year or two before maturing into adults.

<i>Rhynchophorus ferrugineus</i> Pest weevil on palm (oil, coconut, date)

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 long, and are usually a rusty red colour—but many colour variants exist and have often been classified as different species. 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.

<i>Curculio glandium</i> Species of weevil

Curculio glandium, is a species of European carpophagus weevil in the genus Curculio, the acorn and nut weevils. It eats by a rostrum, an elongated snout, that is used for piercing.

<i>Otiorhynchus ovatus</i> Species of beetle

Otiorhynchus ovatus, the strawberry root weevil, is one of the many species in the weevil family (Curculionidae), occurring across Canada and the northern United States. The species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. Its name comes from its affinity for strawberry plants, which form a large part of its diet. They are, however, known to feed on other plants as well. Occasionally the larvae cause serious damage to seedlings and young transplants in plantations and nurseries. It is known to be one of the major pests threatening sub-tropical strawberry farming.

<i>Curculio caryae</i> Species of beetle

The pecan weevil, Curculio caryae is an obligate feeder on the nuts of North American hickories and pecans, most widely recognized as an economically important pest of the pecan, Carya illinoinensis. It has also been observed to infest one Juglans species, the Persian walnut, Juglans regia.

<i>Curculio elephas</i> Species of beetle

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.

<i>Sitona lineatus</i> Species of beetle

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.

Hoplocampa testudinea, the apple sawfly or European apple sawfly, is a species of sawfly in the family Tenthredinidae. It is native to Europe but has been accidentally introduced into North America where it became invasive. The larvae feed inside the developing fruits of the apple tree.

Hypera brunnipennis, the Egyptian alfalfa weevil, is a species of true weevil in the beetle family Curculionidae. The name is often misspelled as brunneipennis in the literature.

<i>Curculio sayi</i> Species of beetle

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.

Tariq Butt is an entomologist in the UK, he is Professor of Biosciences at Swansea University in Wales.

Eucryptorrhynchus brandti, the snout weevil, is an insect in the weevil family. In its native range in China, it causes significant damage to its single host, Ailanthus altissima, tree of heaven. Thus the weevil is under study as a biological control of tree of heaven in regions where the tree is non-native. In particular, the insect acts as a vector for Verticillium nonalfalfae, a soilborne fungus that causes verticillium wilt.

Myllocerus viridanus, often known as sweet potato beetle, pod borer or ash weevil, is a species of weevil native to India and Sri Lanka.

<i>Odoiporus longicollis</i> Species of beetle

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.

References

  1. http://www.kerbtier.de/
  2. http://coleoptera.ksib.pl/search.php?l=en
  3. Archived 2012-05-12 at the Wayback Machine http://www.colpolon.biol.uni.wroc.pl/curculio%20nucum.htm
  4. Hughes, J; Vogler, AP (2004). "The phylogeny of acorn weevils (genus Curculio) from mitochondrial and nuclear DNA sequences: the problem of incomplete data". Molecular Phylogenetics and Evolution. 32 (2): 601–615. doi:10.1016/j.ympev.2004.02.007. PMID   15223041.
  5. LeConte, J.L. & Horn, G.H. 1876. The Rhynchophora of America, North of Mexico. Proceedings of the American Philosophical Society,15: i-xvi, 1-455
  6. M. C. Bel-Venner et al. 2008. Ecophysiological attributes of adult overwintering in insects: insights from a field study of the nut weevil, Curculio nucum. Physiological Entomology doi : 10.1111/j.1365-3032.2008.00652.x
  7. "Archived copy" (PDF). Archived from the original (PDF) on 2014-05-21. Retrieved 2012-03-05.{{cite web}}: CS1 maint: archived copy as title (link) A. Peters. Control of the hazel nut weevil Curculio nucum with entomopathogenic nematodes.
  8. Archived 2014-05-21 at the Wayback Machine B. Paparatti , S. Speranza. Biological Control of Hazelnut Weevil (Curculio nucum L., Coleoptera, Curculionidae) Using the Entomopathogenic Fungus Beauveria bassiana (Balsamo) Vuill. (Deuteromycotina, Hyphomycetes). VI International Congress on Hazelnut 686, 2004 - actahort.org
  9. Guidone, L. (2007). "Early nut development as a resistance factor to the attacks of Curculio nucum (Coleoptera: Curculionidae)". Annals of Applied Biology. 150 (3): 323–329. doi:10.1111/j.1744-7348.2007.00133.x.