(Bursaphelenchus xylophilus): It is a plague caused by a nematode, 1mm long) that develops inside the wood of pine trees and other coniferous species. Attracted by wounds in trees (pruning, felling), the vector insect Monochamus galloprovincialis oviposits, feeding on the larva of the woody tissue of the tree. It is at this stage that the larva can be infected by the nematode present. When mature, the insect infected with the nematode will be able to move to other trees, on which it will feed and to which it will be able to transmit the nematode. Beginning its attack in the resin canals, its seriousness lies in the fact that the pines die inevitably a few months after the inoculation of the nematode.

With several very similar species (Bemisia tabaci, Trialeurodes vaporariorum) the aleuródidos are small insects (1mm) that suck a large amount of sap from the leaves of multiple species of ornamental and agricultural plants. From the underside of the leaves, hundreds of eggs per female hatch in moderate temperature conditions, to later feed as nymphs (N1-N4), secreting honeydew, which causes the formation of bold, reducing transpiration and photosynthesis. They grow to adults, with great capacity for flight, which, together with their multiple annual generations (one every 15-25 days), makes them spread very quickly, making their control very complex. In addition, they inject enzymes into the leaf that paralyze the physiological processes of the plant, stopping the development and normal growth of the plant. They are potential vectors of other diseases.

With a size of 3-4mm, it is polyphagous, although it mainly attacks the genus Platanus. They hibernate as adults, to begin to suck sap and oviposit with the first spring buds, on the underside of the leaves. When feeding, the nymphs secrete honeydew, which favors the sooty mold. They pass into adulthood, thus completing the life cycle, which is repeated 3-5 times per season. The leaves become dispigmented, taking on a leaden gray coloration, ending up drying up and falling prematurely, and causing a lack of vigor in the plant.

Despite its small size (0.5mm), it is a polyphagous species that causes serious damage to many species. Its life cycle of about 10 days and its large number of eggs (100-120) allow it to disperse quickly. It produces silk threads that protect it from predators and prevent photosynthesis. They form colonies on the underside of the leaves, from where they suck sap, forming chlorotic spots and defoliation in severe attacks.

About 2-3mm in size, it specifically attacks the genus Eucalyptus. After spawning, the N1 nymphs move along the leaf until they settle (N2-N5), where they create a sugary shield that protects them while they feed by sucking sap, with a strong secretion of honeydew. The high flight capacity of the adult will allow it to oviposit on other trees which, together with its 3-5 annual cycles, allows it to disperse very quickly. As a result, yellowing and leaf fall will be observed, which leads to a general weakening, which favors the attack of other pests such as Gonipterus, Phorancantha, or fungi, even causing death.

With a size of 2-3mm, it mainly attacks the genus Ficus, and particularly Ficus microcarpa (=Ficus nitida). They present 3-5 generations per year in temperate climates. After spawning, there are 5 nymphal instars (N1-N5), which feed on the plant, especially on the young shoots, causing leaf curling and honeydew secretion. From N3, waxy secretions will also be produced, which give the glass a cottony appearance. They will end as imagos, closing the cycle with a new start. Successive attacks cause serious defoliation, completely drying up parts of the crown, and can cause serious decay that can lead to the death of the specimen, when adding other pathologies. As they are evergreen species, the insect can be active all year round if the weather allows it.

Defoliator of trees of the Quercus genus mainly. About 45-65 mm long, the female lays eggs on her bark before winter, protecting them with plastons of scales on her belly. In the following spring, after hatching, for 1.5 - 2 months, the larvae grow in 5-6 instars, feeding on the leaves before pupating and metamorphosing for 2 weeks, to oviposit before winter and close the life cycle. . As the female does not fly, dispersal to other trees frequently occurs by swaying in the wind of the larvae, which hang from a silken thread, when the host tree is severely defoliated. The damage consists of intense defoliation of the trees, weakening them, affecting their growth and producing the loss of the fruit.

Polyphagous species, which affects numerous ornamental and agricultural species. With a size of 35-60mm, the moth emerges in summer to oviposit, under a silk pouch, on the trunk or branches. The larvae will go to the tender areas, where they feed on the leaves and make galleries, to then penetrate thick wood. In winter they stop their activity to reactivate the following spring and complete their development until summer. They then pupate and metamorphose to complete the annual cycle, although it can also be biennial in cold areas. The galleries cause serious damage, which can trigger the breaking of branches.