WELENSII

Vulgar names: - Synonyms: Cerambyx velutinus Brullé.

Distribution: Scientific name: (Küster). The Cerambyx genus is found throughout Southern Europe, and on the : Iberian Peninsula is located mainly in the Family regions of Extremadura and Andalusia. Cerambycidae.

Cerambyx welensii is a large xylophagous whose larvae feed on the wood of dead, weak or badly damaged parts of different hardwood species. It has a special predilection for the Quercus genus and more specifically for holm oaks () and cork oaks (), causing serious damage to the dehesa woodland.

Characteristics

Foto: Pablo Cobos Suárez The adult's colour is very dark brown, complete their development, reaching a final Foto: Pablo Cobos lightening towards the rear end. Adults are length of 6 to 9 cm, even exceeding the size of 25 to 60 mm long. Females are somewhat the adult . They are ivory in colour, larger than males, and are easily cylindrical in shape, narrowing towards the ends distinguishable because the length of their and with very pronounced body segments. The antennas is less than 2/3 of that of the body, horny plate is dark and highly visible, with two while in males the antennas are longer than strong, serrated jaws. The pupae are large and the body. Both genders have 11 antenna look very similar to adults. They have a pearly segments and strong jaws, as well as nails on colour that darkens as they develop. their legs to grip the bark of the trees. The elytra are very long and rigid. The larvae of this take about 3 years to complete

Bibliography and references: - Junta de Extremadura, Consejería de Agricultura, Desarrollo Rural, Medioambiente y Energía. Plan Forestal de Extremadura. - Sanidad forestal: guía en imágenes de plagas, enfermedades y otros agentes presentes en los montes (Muñoz et al. Madrid, Mundiprensa, 2007). - Instituto del Corcho, la Madera y el Carbón Vegetal. (IPROCOR) - Manual para el seguimiento del estado sanitario de la vegetación arbórea en la dehesa. (Junta de Andalucía. Consejería de Agricultura y Pesca. Consejería de Medio Ambiente). Lifecycle

January February March April May June July August September October November December Larva Pupa Adult Egg

Egg Larva Pupa Adult

Foto: Enrique Casadomet Foto: Pablo Cobos Foto: Enrique Casadomet Foto: Pablo Cobos

Laying takes place from early June to The larvae hatch approximately 10 days Between the months of May and June the Six months after the formation of the mid-September. The eggs are laid one by after laying. They begin to feed on the larva forms a chrysalis, remaining chrysalis, and approximately between the one in the cracks of the bark of the trunk outer layers of the bark and then approximately 6 months in pupal form and months of November and December, the and main branches, in the case of holm penetrate the inside of the trunk or emerging as an adult in the months of adults emerge. These do not leave the tree oak, and in the deepest cracks of the cork branch to feed on the wood. They bore November and December. The pupae are immediately, but remain inside the wood wider and wider feeding galleries as they of the trunk and main branches, in the large and very similar in appearance to the until the following spring, emerging case of the cork oak. The females also lay develop and increase in size, remaining in adults. They are of a pearly colour, which between June and mid-September to mate the eggs under the bark in torn or this state from 2 to 4 years. At the end of damaged areas. The eggs are about 3 mm their development, in the months of May darkens as development progresses. and lay and begin a new cycle. This process in length and ivory-pink in colour. They and June, they bore a gallery towards the of emergence of the adults from the tree is are oval in form with 2 protuberances at outside for the exit of the adult, returning what causes the appearance of holes with the ends that give them a lemon-shaped to the interior of the trunk to form a accumulations of wood dust and appearance. chrysalis. segregations of darkened sap. The average life span is about two months in males and about four months in females. Damages and symptoms The damage caused by this pest is the result of its Another symptom caused by the attack of this pest is the loss of larvae feeding on the wood of the affected trees. This bark in the areas affected by the galleries, due to the lack of sap damage is very characteristic and easy to identify, but circulation. The effects of this damage are the gradual very difficult to distinguish if it has been caused by a weakening of the tree, and the drying out and even breakage of certain species of Cerambycidae. The clearest symptoms the branches due to the loss of resilience of the wood of the presence of the pest are the appearance of perforated by the galleries. In addition to this, the feeding accumulations of wood dust under the exit holes of galleries and adult exit orifices provide easy access for various adults, the appearance of dark sap discharges through fungal diseases. these holes, and the presence in the wood of large galleries that were made by the larvae to feed during Cerambyx attacks are usually associated with sick and decrepit their development. The galleries can be up to 70 cm. in trees or those infected due to pruning wounds, cork extraction length and up to 4 cm. in diameter, with a zig-zag or tearing, which make it easier for the larvae to penetrate the course that penetrates the inside of the trunk and trunk. However, in the event of severe attacks, damage can also destroys the vascular tissues that distribute nutrients occur in relatively young and healthy specimens. throughout the plant. The greatest larval activity usually occurs in the parts of the trunk that receive most sunlight.

Foto: Enrique Casadomet Treatment and prevention

Major Cerambyx attacks are usually preceded by poor management of the dehesa, excessive It is therefore strictly forbidden to use plant protection products and any treatment or pruning, work that damages the tree, or careless and untimely cork removal. Therefore, procedure that reduces the populations of this species. Cerambyx welensii, however, is not good management of the dehesa, with strong, vigorous, healthy trees, is the best means of protected, and where necessary, action can be taken to reduce its populations. The control of prevention against Cerambyx. It is also essential to eliminate possible sources of pest this pest is carried out in its adult phase, since in the other phases, it is very difficult to apply introduction, and this is achieved through the correct and rapid removal of infected, effective treatments, and mass trapping systems with food baits are usually used. There is decrepit and dead specimens. The Cerambyx welensii has several natural enemies that help currently no other type of really effective treatment against this pest. Like Hypoxilun, keep the insect populations under control, including the woodpecker, which consumes a Cerambyx also carry out an important task of decomposition of plant waste in the large number of larvae by penetrating their galleries. It is important to note that one species dehesa, which, added to the fact that they only usually attack dead or decrepit individuals, of Cerambycidae, the , is protected throughout Europe by the Bern makes it necessary to carry out continuous and detailed monitoring of the insect populations Convention, in Annex II: and plant species of Community interest. and their real damage to the trees in order to decide whether or not it is necessary to apply treatments to control their populations.