Identification and Seasonal Abundance of Auchenorrhyncha With a Focus on Potential Insect Vectors of Xylella fastidiosa in Olive Orchards in Three Regions of Greece

Abstract

Studies of the species composition, seasonal appearance, and abundance of Auchenorrhyncha in olive crops is of paramount importance to reduce the potential of Xylella fastidiosa to invade new areas. As similar investigations had not previously been conducted in Greece, extensive surveys were undertaken in olive orchards located in three of the most important regions for olive production in central Greece (Fthiotida), south-central Greece (Attica), and southern Greece (Chania). Surveys took place over a 13-mo period, using Malaise traps examined on a monthly basis. Results showed high levels of species richness in the olive orchards, and the Auchenorrhyncha diversity varied among the regions surveyed. Most of the species listed as potential vectors of X. fastidiosa in Europe were found in relatively low numbers. Furthermore, many insects of the Deltocephalinae subfamily were found, whose behavior as vectors should be further studied. The dominant and most frequent species found in the three regions were tested and found not to be associated with transmission of the bacterium. This study may serve as an alert, showing that the most commonly found species differ from those identified in similar studies in Italy, and thus other species should be examined as potential vectors. The results of the present study provide new insights into the seasonal abundance and dynamics of potential vectors of X. fastidosa in several regions of Greece, and also provide information that may prove valuable for the effective containment and eradication of this threat.

Spittlebugs of Mediterranean Olive Groves: Host-Plant Exploitation throughout the Year

“…During the summer, the situations in Apulia and Liguria olive groves were clearly different: In Apulia, the number of spittlebugs collected in the olive agroecosystem during hot months was low, while in Liguria, spittlebugs were collected inside the olive groves in relatively high numbers until autumn. The continuative presence of spittlebugs on olive trees and in the agroecosystem is probably related to the less severe water stress of olive trees growing in Liguria compared to Apulia, Spain, and Greece, where adults almost disappear in summer from the olive agroecosystem [1,[5][6][7]34]. Such a difference in crop exploitation may have important consequences if X. fastidiosa were introduced in Liguria, since the prolonged presence of vectors on the crop trees may contribute to the higher spread of the bacterium.…”

“…The most important differences between the two areas concerned (i) host-plant association that, besides being determined by insect preference, was driven by ground cover floral composition, (ii) summer colonization of olive trees by adults, that visited olive canopies in a higher number and for a prolonged period in Northern Italy, and (iii) spittlebug population level that appeared to be higher in Northern Italy. Actually, several reports indicated that the populations of P. spumarius and of other spittlebug species are quite low under warm and dry Mediterranean conditions [6,7], although with some exceptions [8]. The knowledge of preferential plant selection by both nymphal and adult stages of the main X. fastidiosa vector in Europe may allow designing more effective integrated pest management programs, so far based on soil tilling to eliminate nymphs and on insecticide applications targeting adults on the crop canopy.…”

Distribution and Relative Abundance of Insect Vectors of Xylella fastidiosa in Olive Groves of the Iberian Peninsula

“…Furthermore, other protocols and sampling techniques for studying migration of spittlebugs from cultivated to unmanaged areas should be considered. Accordingly, Tsagkarakis et al (2018) [42] proposed Malaise traps as an alternative sampling method of Auchenorryncha in olive groves. These authors stated that Malaise trapping was better than sweep netting for studies on the species richness and the identification of potential vectors of X. fastidiosa .…”

“…Tsagkarakis et al (2018) [42] described a bivoltine cycle for spittlebugs in Greece. Likewise, Drosopoulos and Asche (2001) [50] described the bivoltine life cycle of P. spumarius in Greece.…”

Biology and Prevalence in Northern Italy of Verrallia aucta (Diptera, Pipunculidae), a Parasitoid of Philaenus spumarius (Hemiptera, Aphrophoridae), the Main Vector of Xylella fastidiosa in Europe

“…While the amount of information on the phenology and ecology of P. spumarius and closely related species is rapidly increasing [11][12][13][14][15][16][17][18][19], the literature on biological control agents of these insects is very scarce. Indeed, it is restricted to reports on the presence of egg parasitoids of the genus Ooctonus (Hymenoptera Mymaridae) and Centrodora (Hymenoptera Aphelinidae), the endoparasitoid Verrallia aucta Fallén (Diptera Pipunculidae) and few uncharacterized entomopathogenic fungi (revised in [8,14]).…”