Ranean and the Supra-Mediterranean belts and show affinity to siliceous, loose and permeable substrates common of hygrophilous environments. Though there exist pure or virtually pure formations of Q. suber, this species is usually also integrated in mixed Quercus formations, exactly where can Anti-infection| coexist with diverse species which include Q. ilex an Quercus faginea (Lamarck), keeping the standard physiognomy with the dehesa [10]. The conservation status of dehesas is threatened, amongst other things, by the progressively much more evident “decline syndrome”, which consists inside the improvement of a set of decay symptoms that occur without the need of a fixed pattern but following a sequential chronology. The principle causes of this decline have already been categorized in three groups which act synergically [11]: I. II. Predisposing components to which the trees are permanently exposed, including harsh climatic circumstances, edaphic changes and inadequate silvicultural practices; Aggravating components which act throughout a short but intense period of exposure, like the action of defoliating insects such as the Lepidoptera Lymantria dispar (L.) and Tortrix viridana L. and insect borers like C. undatus (our study topic); Contributing things, which lead to death of poor wellness or weakened trees, like pathogenic fungi in the genus Phytophthora and Pythium.III.For the duration of the last decades, the decline of Quercus spp. has impacted millions of specimens throughout their distribution region [12], which has got an awesome economic repercussion, lessening the cork production involving 40 and 89 , according to the geographical zone. The cork oaks impacted by this syndrome are much more vulnerable to suffer the attack of pathogens, defoliators and xylophages. Adults of C. undatus are diurnal, thermophiles and herbivorous oligophagous [13]. The adults emerge in spring from inside of trunks and major branches, causing exit holes “D” shaped in the bark. The females lay eggs on the bark surface or inside cracks. Right after hatching, the neonatal larvae move towards the phloem and commence to feed by constructing characteristic tunnels. Usually, the larva goes through four stages prior to winter and, immediately after the last phase, the larva remains within a quiescent state or pupa until late spring, when it emerges as an adult [14]. Despite the fact that C. undatus can feed on a number of Quercus species, its damages create higher financial losses inside the case from the cork oaks. Throughout their development, they elaborate sinuous feeding galleries in the phellogen layer, reaching even 2 m length and 3 mm width, harming the regenerative capacity of your tree [4]. In the following years, it could possibly be observed that the new layers of cork show hypertrophied areas corresponding for the galleries filled with excrements. These scars, commonly called `cork shingles’ because of its sinuous morphology (Figure 1a), significantly devalue the cork value, thus threatening the sustainable exploitation of cork-oaks forests [15]. Components influencing the presence of C. undatus are tree density, presence of understory, age, well being and height of trees, solar orientation and drought tension [16]. Like in the case of other borers, the manage of C. undatus is challenging to perform because the larva (damaging stage) is Viridiol web endophytic, undetectable and virtually inaccessible [17,18].Forests 2021, 12,3 ofFigure 1. Lesions in Q. suber trunk performed by boring insects. (a) “cork shingles” by C. undatus, in which three interceptions are visible; (b) “chicken feet” by R. grassei, with one interception vi.