Coleoptera
Coleoptera (beetles) have chewing-type mouthparts, and are protected by rigid armor. Most can fly, although without great skill, which allows them to be transmitted from one plant to another, where they can be serious pests.
They undergo complete metamorphosis. In larval stages they are more voracious and, after pupating, they become adults (imago), with a mainly reproductive function, although they also tend to feed during their sexual maturation.
They can have several generations per year and have a wide variety of diets. Those that mainly cause pests are phytophagous, which feed mainly on leaves, such as chrysomelids and xylophagous, which feed on the vascular tissue of the trunk, such as curculionids (eg: Tomicus, weevil red, diocalandra...), the scotch (eg elm borer) or the buprestids (eg: emerald ash borer).
Elm borer
Winter
Spring
Summer
Autumn
(Scolytus multistriatus): Curculionid, between 2 and 3mm, which feeds mainly on trees of the genus Ulmus spp. Excavates subcortical radial galleries. After hibernating in the galleries, in spring it emerges to penetrate and oviposit in new trees, whose larvae will feed until autumn, to close the cycle. In addition to subcortical damage, they are vectors of the Dutch disease (Ceratocystis ulmi).
Tomicus
Winter
Spring
Summer
Autumn
(Tomicus destruens, pinniperda, spp.): Curculionid whose adult (imago) reaches 4 to 4.5 mm in length. The female oviposits several times, throughout the winter in the subcortical galleries that she digs in the trunk of the pine trees (resin volcano). During the winter and until spring the larvae are born and feed in galleries perpendicular to the maternal one, to pupate and later exit through a hole (without resin). They climb to the crown, where they feed on the marrow of the terminal twigs, which will fall to the ground, until they reach sexual maturity and oviposit again in winter, closing a single annual cycle. The galleries interrupt the flow of sap, to the point of causing the death of the plant.
Elm leaf beetle
Winter
Spring
Summer
Autumn
(Xanthogaleruca luteola): With the genus Ulmus spp. As its only host, it hibernates in the bark or in the immediate vicinity of the tree, to emerge in spring and oviposit on the underside of the leaves, while perforating them. The larvae feed on the parenchyma of the leaves, which remain transparent, giving the tree a skeletal appearance. Later they descend to the trunk, where they metamorphose, to complete a cycle of 2 to 2.5 months, with up to 4 generations per year, weather conditions permitting. Successive attacks weaken the tree, making it vulnerable to the entry of other pests such as the elm borer, or diseases, such as ghetto disease, of which the borer is a vector.
Diocalandra
Winter
Spring
Summer
Autumn
(Diocalandra frumenti): Curculionid of small size (6-8mm). With several generations per year, the adult oviposits at the base of the petioles, where, upon emerging, the larva feeds voraciously, making galleries towards the interior, where it finally pupates and metamorphoses. Once male and female adults mate, they complete their life cycle in 2.5 to 3 months. The hosts are preferably palms of the genus Phoenix, although Washingtonia spp. and Cocos nucifera among others. After successive generations, the palm tree will die. This pest has also been described as a vector of fungi such as Gliocladium vermoesenii and Thielaviopsis paradoxa.
Red Weevil
Winter
Spring
Summer
Autumn
(Rhynchophorus ferrugineus): large curculionid (adult 2 to 5cm). With two generations per year, its different stadiums coexist throughout the year. After emerging from the clutches in the crown, the larvae excavate galleries towards the interior, where they feed, until they pupate and metamorphose into an adult, returning females and males to mate to close the cycle of 5 to 6 months. They preferentially attack palm trees of the genus Phoenix, although they also occasionally attack those of the Washingtonia. If not controlled in time, it causes the death of the palm tree.