Antonios E. Tsagkarakis

Seasonal population fluctuation and spatial distribution of Orthoptera in two grassland areas of Attica – Greece

The aim of this study was to investigate the seasonal population fluctuation of orthopteran assemblages and determine the spatial distribution of the most abundant species of Orthoptera among two habitats in Greece. A 2-year study was performed in a lowland area and in a mountain grassland area. The family of Acrididae represented almost 75% of the total orthopteran relative abundance in both sampling areas. Dociostaurus maroccanus and Chorthippus bornhalmi were found to be the most abundant species in the lowland and the mountain sampling stations, respectively. Most populated species were spatially aggregated in the lowland station, whereas the abundant species were found to be distributed either aggregately or randomly among sampling units in the mountain area. Shannon–Wiener index estimate was higher for the lowland in 2007 than for the mountain, whereas the opposite was found in 2008. The factors affecting the population dynamics of Orthoptera are discussed.

Phyllocnistis citrella and its parasitoids in three citrus species in Greece.

The relative abundance as well as the percentage of parasitism of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and its parasitoids were studied in a citrus orchard with orange, mandarin and lemon trees in Greece. Infestation of P. citrella on each citrus host, as expressed by the number of mines per leaf, was significantly higher on lemon than on mandarin. The P. citrella parasitoid complex included the native species Neochrysocharis formosa and Pnigalio pectinicornis, as well as the introduced Citrostichus phyllocnistoides. The most abundant of those was N. formosa in all of the citrus species. The average percentage of parasitism was 13.1%, 13.8% and 11.7% on orange, mandarin and lemon, respectively. No significant differences in parasitism rate by each of the three parasitoid species separately were recorded among the three citrus species.

Introduced and native parasitoids of Phyllocnistis citrella Stainton in Greece: short term post-release evaluation

The Citrus Leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is considered an important pest of citrus, damaging mainly nursery plants. In Greece it was first recorded on the island of Rhodes in 1995 and rapidly spread to all citrus growing areas of the country. Due to its wide expansion and damage, efforts were initiated to control this pest with biological control agents. For this purpose, a number of exotic parasitoids, such as Citrostichus phyllocnistoides (Narayanan), Quadrastichus sp. Girault and Semielacher petiolata (Girault) (Hymenoptera: Eulophidae), were introduced, reared in insectaries and released in several regions of Greece. The species composition and the seasonal abundance of the native parasitoids, as well as the recovery of the released parasitoids, were investigated in weekly samplings during 1998 and 1999 in a citrus orchard in Argolis district. Results showed that among the released parasitoids, only C. phyllocnistoides was recovered. Among the native parasitoids, Neochrysocharis formosa (Westwood), Pnigalio pectinicornis (L.) and Cirrospilus sp. Westwood (Hymenoptera: Eulophidae) were identified. The most abundant parasitoid species was the exotic C. phyllocnistoides. The highest percent of parasitism in 1999 increased approximately by 46% compared with that of the previous year. The percent of parasitism increased to its maximum level during November, at the end of the sampling period in both years, when the population density of C. phyllocnistoides was high.

Composition and seasonal abundance of mites on three citrus species in Greece

In order to compare the composition and the relative abundance of the mite species occurring on three citrus species, sweet orange, sour orange and mandarin, 25 monthly samplings were conducted on mandarin in a citrus orange orchard in Argolis county, Greece, from June 2004 to June 2006. In the examined samples, mites from 15 taxa belonging to 3 orders were identified. These included nine predatory taxa belonging to three families (Phytoseiidae, Cheyletidae, Bdellidae), four primarily fungivorous taxa in the family Tydeidae and Tarsonemidae, two phytophagous taxa belonging to families Tetranychidae and Eriophyidae and one saprophagous taxon (Cryptostigmata). From the aforementioned taxa, 14 were found on sour orange, 13 on sweet orange and 9 on mandarin. Tydeus californicus was the only “dominant and constant” taxon in all the three citrus species. Lorryia sp. nr. formosa was “dominant and constant” on mandarin, while on sweet orange was “recedent and constant” and on sour orange was “influent and accessory”. Aceria sheldoni was “dominant and accessory” on sour orange, while it was “recedent and accidental” on sweet orange and totally absent on mandarin. All the other taxa were “influent”, or “recedent”. Population of Tydeus californicus in all citrus species was higher in fall, winter and early spring, while in summer it was declining. The mean population level on sweet orange was significantly higher compared with mandarin. A similar population pattern was observed in L. sp. nr. formosa, with the expectance of mandarin during 2005. Tetranychid population on sweet orange was the highest, but no significant difference was observed on the other two species. The A. sheldoni population was significantly higher on sour orange compared with sweet orange, while on mandarin was absent. Also, predatory mites’ population was significantly higher on sour orange than on sweet orange and mandarin. They were present in the samples for long periods in all citrus species.

Composition and seasonal abundance of mites associated with citrus in Greece

ABSTRACT In order to estimate the composition of the mite taxa occurring in citrus and their seasonal and relative abundance, 25 monthly samplings were accomplished in an orange orchard in “Nea Kios” region, Argolis county, Greece, from June 2004 to June 2006. In the examined samples, mites from 19 taxa belonging to 10 families in 3 orders were identified. These included nine predatory species belonging to three families (Phytoseiidae, Cheyletidae, Bdellidae), four primarily fungivorous species in the family Tydeidae and Tarsonemidae, five phytophagous species belonging to two families (Tetranychidae, Eriophyidae), and one saprophagous taxon (Cryptostigmata). The only “dominant and constant” species was Tydeus californicus (Banks). Lorryia formosa Cooreman was “recedent and constant,” while Panonychus citri (McGregor), Pronematus sp., Euseius stipulatus (Athias-Henriot), and Cryptostigmata were marked as “recedent and accessory.” All the other taxa were “recedent and accidental.” Population of T. californicus was in general higher in fall, winter, and early spring. A similar population fluctuation was observed in L. formosa, in relatively lower population density. Tetranychids had remarkable population densities from June 2004 to December 2004 and from February 2005 to May 2005. Phytoseiids were present in long intervals, while their population peaked in June 2004 and April 2005. The role of tydeids as a very convenient prey to conserve phytoseiid population, when primarily phytophagous mites are absent, is to be considered.

New records and updated checklist of Cicadomorpha (Hemiptera: Auchenorrhyncha) species from Greece

Seventeen auchenorrhynchan species of the family Cicadellidae are recorded from Greece for the first time: Euscelidius variegatus (Kirschbaum 1858), Euscelis ohausi (Wagner 1939), Psammotettix notatus (Melichar 1896), Psammotettix striatus (Linnaeus 1758), Psammotettix sabulicola (Curtis 1837), Anzygina honiloa (Kirkaldy 1906), Arboridia versuta (Melichar 1897), Edwardsiana ishidae (Matsumura 1932), Edwardsiana tersa (Edwards 1914), Eupteryx decemnotata (Rey 1891), Eupteryx curtisii (Flor 1861), Eupteryx rostrata (Ribaut 1936), Frutioidia sanguinosa (Rey 1891), Zygina rosea (Flor 1861), Zygina suavis (Rey 1891), Zygina tiliae (Fallen 1806), Anaceratagallia frisia (Wagner 1939). Faunistic and distributional data notes are given for each species and a complete, updated species checklist for Greece is provided.

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

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.

The occurrence of Pealius mori (Takahashi), Pealius machili Takahashi and Paraleyrodes minei Iaccarino (Hemiptera: Aleyrodidae) infesting Morus alba L. in Greece

Summary Pealius machili (Takahashi, 1935), the mulberry whitefly Pealius mori (Takahashi, 1932) and the nesting whitefly Paraleyrodes minei (Iaccarino, 1990) were found infesting mulberry in Greece. The first species is reported for first time outside China, the second species was recorded for the first time in Greece, and the third species represents a new association. A brief description, illustrations and information on distribution and potential damage and control of each species are provided. The first results showed that nymphs were parasitized, although at a low rate. The reported species developed high infestation levels and thus may become major pests of mulberries in the eastern Mediterranean region.