Sterile Insect Technique (SIT) field trial targeting the suppression of Aedes albopictus in Greece.

The sterile insect technique (SIT) involves releasing large numbers of sterile males to outcompete wild males in mating with females, leading to a decline in pest populations. In the current study, we conducted a suppression trial in Greece against the invasive dengue vector mosquito Aedes albopictus (Skuse) through the weekly release of sterile males for 22 weeks from June to September 2019. Our approach included the long-distance transport of sterile mosquitoes, and their release at a density of 2,547 ± 159 sterile males per hectare per week as part of an area-wide integrated pest management strategy (AW-IPM). The repeated releases of sterile males resulted in a gradual reduction in egg density, reaching 78% from mid-June to early September. This reduction remained between 70% and 78% for four weeks after the end of the releases. Additionally, in the SIT intervention area, the ovitrap index, representing the percentage of traps containing eggs, remained lower throughout the trial than in the control area. This trial represents a significant advance in the field of mosquito control, as it explores the viability and efficacy of producing and transporting sterile males from a distant facility to the release area. Our results provide valuable insights for future SIT programmes targeting Ae. Albopictus, and the methodology we employed can serve as a starting point for developing more refined and effective release protocols, including the transportation of sterile males over long distances from production units to intervention areas.

Title: Essai sur le terrain de la Technique de l'Insecte Stérile (TIS) ciblant la suppression d'Aedes albopictus en Grèce. Abstract: La technique de l'insecte stérile (TIS) consiste à libérer un grand nombre de mâles stériles pour supplanter les mâles sauvages lors de l'accouplement avec les femelles, entraînant ainsi un déclin des populations de nuisibles. Dans la présente étude, nous avons mené un essai de suppression en Grèce contre le moustique vecteur invasif de la dengue, Aedes albopictus (Skuse), par le biais de la libération hebdomadaire de mâles stériles pendant 22 semaines de juin à septembre 2019. Notre approche comprenait le transport sur de longues distances de moustiques stériles, et leur lâcher à une densité de 2 547 ± 159 mâles stériles par hectare et par semaine dans le cadre d'une stratégie de lutte intégrée contre les nuisibles à l'échelle de la zone (AW-IPM). Les lâchers répétés de mâles stériles ont entraîné une réduction progressive de la densité des œufs, atteignant 78 % de la mi-juin au début septembre. Cette réduction est restée entre 70 % et 78 % pendant quatre semaines après la fin des lâchers. De plus, dans la zone d'intervention de la TIS, l'indice d'oviposition, représentant le pourcentage de pièges contenant des œufs, est resté plus faible que dans la zone témoin tout au long de l'essai. Cet essai représente une avancée significative dans le domaine de la lutte contre les moustiques, car il explore la viabilité et l'efficacité de la production et du transport de mâles stériles depuis une installation éloignée vers la zone de lâcher. Nos résultats fournissent des informations précieuses pour les futurs programmes de TIS ciblant Ae. albopictus et la méthodologie que nous avons utilisée pourra servir de point de départ pour développer des protocoles de libération plus raffinés et plus efficaces, y compris le transport de mâles stériles sur de longues distances depuis les unités de production jusqu'aux zones d'intervention.

Insights into the Diversity and Population Structure of Predominant Typhlocybinae Species Existing in Vineyards in Greece.

Insects of the subfamily Typhlocybinae (Hemiptera: Cicadellidae) are pests of economically important agricultural and horticultural crops. They damage the plants directly or indirectly by transmitting plant pathogens, resulting in significant yield loss. Several leafhoppers of this subfamily use vines as hosts. Accurate and rapid identification is the key to their successful management. The aim of this study is to determine the Typhlocybinae species that exist in vineyards all over Greece and investigate the relationship between them. For this purpose, yellow sticky traps were placed, morphological and molecular data were collected, and phylogenetic models were analyzed. The mitochondrial marker Cytochrome Oxidase Subunit I (mtCOI) was applied for the DNA and phylogenetic analysis. The combination of morphological and molecular data resulted in identifying the existence of six different species all over Greece: Arboridia adanae, Asymmetrasca decedens, Hebata decipiens, Hebata vitis, Jacobiasca lybica and Zygina rhamni. Forty-eight different haplotypes were found to exist in the different regions of the country.

Knowledge, Attitude, and Practices Survey in Greece before the Implementation of Sterile Insect Technique against Aedes albopictus.

Community involvement in Aedes albopictus management can be very efficient and result in raising awareness among citizens. Toward this end, a door-to-door campaign can encourage active community participation in vector control. The current study describes the results of an intervention where a KAP (knowledge, attitude, practices) survey tool was paired with a door-to-door campaign and was implemented as an intervention method in Vravrona area (Attica, Greece) before the release of sterile males (sterile insect technique, SIT) against Aedes albopictus. The KAP tool was used to shed light on the knowledge, practices, and attitudes of local community members in order to better prepare and motivate participation in household mosquito control and to assess current understanding of SIT. Each household also received specific information about mosquito source habitat in their own yards at the time of the initial KAP survey. These household data were complemented by standardized mosquito trapping in the municipality. Our findings indicate that citizens' attitude toward SIT ranged from indecisive to fully supportive, while 77.5% of the respondents agreed that the SIT has many advantages over chemical control methods. Furthermore, the results demonstrate that using the door-to-door campaign as an intervention and prerelease method before SIT can suppress the initial mosquito population and potentially improve its efficacy. Lastly, we show that the presence of local municipality officials during door-to-door visits was associated with increased willingness from the residents to participate in the intervention.

Efficacy and residual activity of commercially available entomopathogenic nematode strains for Mediterranean fruit fly control and their ability to infect infested fruits.

BACKGROUND: Entomopathogenic nematodes (EPN) show potential in controlling larvae of the Mediterranean fruit fly (medfly) Ceratitis capitate, but previous studies mainly concern species and strains that are not commercially available. The use of EPN for control of Mediterranean fruit fly is further hampered by the cost of using nematodes. In this study, the efficacy and residual activity of commercial strains of three EPN species, Steinernema carpοcapsae, S. feltiae and Heterοrhabditis bacteriοphοra medfly) C. capitata, in the soil substrate and inside fruits were evaluated. RESULTS: Suspensions of these species were applied at a dose of 1.5 mi m-2 on a soil substrate wherein medfly larvae were added sequentially for a period of 4 weeks post application at 20 °C. S. feltiae provided the highest suppression up to 50% as assessed by adult medfly emergence because it had the highest immediate activity and long residual activity. Furthermore, S. feltiae, and to a lesser degree S. carpocapsae, were able to move and infect medfly larvae inside infested apples and oranges left in the surface of the substrate wherein EPN were applied, reducing significantly adult medfly emergence (60-78%). CONCLUSION: These results support the efficacy and feasibility of applying a single, relatively low dose of S. feltiae in autumn, off-season, targeting overwintering medfly larvae with the scope of reducing the number of adult medflies emerging later in the new season.

Reduction in Egg Fertility of Aedes albopictus Mosquitoes in Greece Following Releases of Imported Sterile Males.

Aedes albopictus, an invasive mosquito species, is currently well established in many European countries, posing high risks to human health. A preliminary trial using repetitive releases of irradiated sterile male mosquitoes was designed, implemented and evaluated for the first time in Greece. The main scope of this trial was to investigate the efficacy of sterile insect technique (SIT) on wild population egg hatch rate in Greece using mass-produced sterile male mosquitoes from another country (Italy). The study was conducted in Vravrona area, close to Athens International Airport (Attica Region). The number of eggs laid in ovitraps was similar in all intervention and control plots. However, a significant reduction in egg hatch rate was recorded in the SIT plot in comparison with both control plots starting two weeks after the first release. This trial validates the logistics (transportation, releases handling and monitoring) as a major step towards implementing efficient, environmentally safe control approaches as an additional tool against the invasive Aedes species in Greece and more widely in Europe.

A Comparison of Adult Mosquito Trapping Methods to Assess Potential West Nile Virus Mosquito Vectors in Greece during the Onset of the 2018 Transmission Season.

West Nile virus (WNV) threatens the health of humans and equines worldwide. Culex (Cx.) pipiens complex mosquitoes are major vectors but numerous other species have been implicated. Due to variations in blood-feeding behaviour, Cx. pipiens biotypes and hybrids influence transmission, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines. In this study, mosquitoes were collected in May-June 2018 during the early period of the transmission season from two regional units of Greece, where WNV cases had been reported in the previous four years (Palaio Faliro and Argolida). A total of 1062 mosquitoes were collected with Biogents Sentinel 2 traps collecting both a greater number of all mosquito species and the Cx. pipiens complex than CDC miniature light traps or Heavy Duty EVS traps. Molecular identification confirmed additional species including Aedes albopictus. The proportion of Cx. pipiens biotypes in Palaio Faliro was 54.5% pipiens, 20.0% molestus and 25.5% hybrids. In Argolida, the collection comprised 68.1% pipiens biotype, 8.3% molestus biotype and 23.6% hybrids. Screening resulted in WNV detection in three females of the pipiens biotype and in one hybrid. As hybrids play a role in spill-over transmission, these findings highlight the importance of entomological surveillance programs incorporating molecular xenomonitoring as an early warning before human cases at the onset of the transmission season.

Evaluation of Two Lactic Acid Bacteria Starter Cultures for the Fermentation of Natural Black Table Olives (Olea europaea L cv Kalamon).

The production of Greek-style natural black table olives remains an empirical process relying on spontaneous fermentation despite its economic significance. For this reason producers often resort to increased NaCl concentration of the brine to secure quality of the product. In this study we employ two lactic acid bacteria Leuconostoc mesenteroides subsp. mesenteroides Lm139 and Lactobacillus pentosus DSM 16366 as starters in separate laboratory low salinity fermentations of "Kalamon" cultivar olives, processed according to the Greek-style method. L. mesenteroides subsp. mesenteroides Lm139 was previously isolated from Kalamon olives laboratory spontaneous fermentations, while L. pentosus DSM 16366 was isolated from fermenting green olives prepared according to the Spanish-style method. Spontaneous olives fermentation was also performed as a control. Microbiological and physicochemical analyses of the brines revealed that the use of the starters had a significant effect on the olives fermentation, leading to a faster acidification due to the more efficient consumption of soluble sugars in the brines. The final pH value reached by each starter culture used indicates a successful lactic fermentation. The production of lactic acid by the starters and the concomitant drop of the pH value proved to inhibit enterobacteria in a shorter period of time compared to the spontaneous fermentation. Concluding, the use of either of the two lactic acid bacteria as starters in Greek-style Kalamon olives fermentation could lead to a more controllable fermentation at lower salinities. The resulting product could be of higher quality with extended shelf-life while being at the same time safer for the consumer.

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.