N. G. Emmanouel

Newly isolated bacterial strains belonging to Bacillaceae (Bacillus sp.) and Micrococcaceae accelerate death of the honey bee mite, Varroa destructor (V. jacobsoni), in laboratory assays

Newly isolated bacterial strains belonging to Bacillaceae (Bacillus sp.), Micrococcaceae and three unidentified strains were tested for their pathogenicity against the mite, Varroa destructor. The Bacillus sp. strain and two of the strains belonging to the Micrococcaceae family significantly decreased the time for 50% mortality of the mite population (up to 57%) and hence may be potential control agents. In in vitro bioassay whole cells, extracellular broth and cellular extract of the Bacillus sp. strain effectively killed the mites, suggesting that both endotoxins and exotoxins contributed to the killing.

Study of Culex tritaeniorhynchus and species composition of mosquitoes in a rice field in Greece

Mosquito species composition and seasonal abundance were studied in a rice field in western Greece over a three-year period (2009-2011). A total of 11,716 larvae and pupae of mosquitoes were recorded, representing seven species, namely Aedes caspius (Pallas), Anopheles hyrcanus (Pallas), Anopheles sacharovi Favre, Culex theileri Theobald, Culex tritaeniorhynchus Giles, Culex pipiens Linnaeus, Uranotaenia unguiculata Edwards and belonging to four genera. Cx. tritaeniorhynchus constituted the most abundant species. It is the second recorded occurrence of this species in Greece, but the first time that a high population of this mosquito species is recorded in the country. In all three years, the total population density of mosquitoes was found to be higher in early August. The number of immatures of all species was found higher in 2009 and 2010 than in 2011, as well was that of the Cx. tritaeniorhynchus adults derived from the rearing of the collected immatures. This regularity is probably due to the lack of water in the rice field in early August 2011. Cx. tritaeniorhynchus was found to be the most abundant species after the rearing of immatures representing 85.1%, 93.5% and 96.1% of the total number of the mosquito adults in 2009, 2010 and 2011, respectively. The rice culturing practices may have affected the seasonal occurrence of mosquito immatures in all of the study years.

Discrimination of Two Natural Biocontrol Agents in the Mediterranean Region Based on Mitochondrial DNA Sequencing Data

Macrolophus pygmaeus and M. melanotoma (Hemiptera: Miridae) are biological control agents used in greenhouse crops, the former preferring plants of the Solanaceae family and the latter the aster Dittrichia viscosa. The discrimination of these species is of high significance for effective biological pest control, but identification based on morphological characters of the host plant is not always reliable. In this study, sequencing analysis of mitochondrial gene segments 12S rDNA and COI has been combined with crossing experiments and morphological observations to develop new markers for Macrolophus spp. discrimination and to provide new data on their genetic variability. This is the first comprehensive research in Greece on M. pygmaeus and M. melanotoma genetic variability based on sequencing data from 12S rDNA and COI gene segments. The relationship of this variability to host plant preference must be investigated in an agricultural ecosystem.

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.

New records of phytoseiid mites from greece with descriptions of two new species of Typhlodromus scheuten (Acarina: Phytoseiidae)

Abstract Six species of phytoseiid mites, Amblyseius judaicus (Swirski & Amitai), A. meridionalis (Berlese), Typhlodromus calabriae (Ragusa & Swirski), T. carmonae Chant & Yoshida-Shaul, T. commenticius Livshitz & Kuznetsov and T. simplex (Chant) are recorded for the first time in Greece. Females of Typhlodromus olympicus n.sp. found on Buxus sempervirens L. and Juniperus sp., and T. kykladiticus n..sp. found on Spartium junceum L., are described and illustrated.

Two new species of Amblyseius berlese (Acari: Phytoseiidae) from Greece

Abstract Adult females of two new phytoseiid species, Amblyseius keae and Amblyseius hymetticus, are described and illustrated. The former species was collected from Quercus aegilops L. and the latter from an undentified plant of the family Labiatae in Greece.

A qualitative and quantitative study of mites in similar alfalfa fields in Greece

The present study investigated the mite fauna and the relative abundance of mites present in foliage and litter of two adjacent and similar alfalfa fields, differing only in the number of cuttings, in Kopais Valley (Central Greece) through 2008–2010. We also examined the relationship between assemblage patterns of Mesostigmata, Oribatida and Prostigmata by comparing their population fluctuation, population density, species richness and diversity. Spatial distribution of common dominant and influent mite species was also estimated. Our results showed that both fields supported a very rich and similar mite fauna with eight new species records for alfalfa of Greece, although these species have been previously reported from other habitats in Greece. The pattern of population fluctuation in foliage was similar in both fields, unlike the fluctuation in litter. Population density significantly differed between fields, being higher in the less harvested field, except Prostigmata. Species richness in litter was higher in the less harvested field, whereas it was higher in the foliage of the more harvested field, apart from that of prostigmatic mites in litter, which was higher in the more harvested field, and that of oribatid mites in foliage, which was higher in the less harvested field. The diversity of mites was higher in the more harvested field, with the exception of prostigmatic mites. The spatial distribution of mites in foliage and litter was aggregated in both fields. Our results indicate that despite the considerable similarity of the study fields, the different harvesting frequency might have disturbed differently the mite communities hosted in foliage and litter.

New records of phytoseiid mites from Greece with a description of the larva of Typhlodromus erymanthii Papadoulis & Emmanouel (Acarina: Phytoseiidae)

Abstract Eight species of phytoseiid mites, Amblyseius cucumeris (Oudemans), A graminis Chant, A. insuetus Livshitz & Kuznetsov, A marginatus (Wainstein), A nemorivagus Athias-Henriot, A setosus (Muma), Typhlodromus erevanicus (Wainstein & Arutunjan) and T.peculiaris (Kolodochka) are recorded for the first time in Greece. The larva of Typhlodromus erymanthii Papadoulis & Emmanouel is described and illustrated. The ontogenetic development of the idiosomal chaetotaxy of this species also is given.

Mite fauna in foliage and litter of Medicago species in Greece

Foliage and litter samples of 10 Medicago species were collected in Greece during a 2-year study in order to record the mite fauna. The Medicago species comprised cultivated and wild plants of the Greek flora, including one endemic species of Crete. One hundred and nine taxa for the Acari fauna were recorded, among them new taxa for the Acari fauna of Greece as well as for some of the Medicago species collected.

Bakerobryobia, a new genus of bryobiini (Acari:Tetranychidae) from Flomis fruticosa L.

Abstract A new genus related to Bryobia Koch, 1836, viz. Bakerobryobia, along with the type-species, B. ylikiensis spec. nov., is described.