Search Results (70)

Dysbiosis is a strategy to control insect pests through disrupting symbiotic bacteria essential for their life cycle. The olive fly, Bactrocera oleae, has been considered a suitable system for dysbiosis, as the insect is strictly dependent on its unique symbiont Candidatus Erwinia dacicola. Here, we review older and recent results from studies of the interaction of the symbiont and its host fly. We then discuss possible methods for disrupting the symbiosis as a means to control the fly. Specifically, we summarize studies using microscopy methods that have investigated in great detail the organs where the bacterium resides and it is always extracellular. Furthermore, we discuss how genome sequences of both host and bacterium can provide valuable resources for understanding the interaction and transcriptomic analyses that have revealed important insights that can be exploited for dysbiosis strategies. We also assess experiments where compounds have been tested against the symbiont. The hitherto limited efficacy in decreasing bacterial abundance suggests that novel molecules and/or new ways for the delivery of agents will be important for successful dysbiosis strategies. Finally, we discuss how gene drive methods could be implemented in olive fly control, though a number of hurdles would need to be overcome. Full article

Bactrocera oleae (Rossi) (Diptera: Tephritidae) is a key pest of olive groves. Adult monitoring is carried out by means of attractant traps of different shapes, which give relevant information for pest control such as the presence of adult flies in the field and their trend, female maturity and sex ratio. However, it is still not entirely clear whether a given density is sufficient for providing a reliable representation of flies in an olive grove. To investigate this question, an experiment was planned, consisting of arranging a high-density network of unbaited sticky panels (UTs) between panels baited with ammonium carbonate (BTs) deployed at a density of 2 traps/ha. The experiment was carried out in Greece, Italy, Lebanon, Spain and Tunisia. The percentage of BT over UT catches varied significantly among the different countries, with BTs ranging from 82% of catches in Italy to 27% in Greece. The Pearson correlation between BTs and UTs was significant under high captures but not significant at low densities. The index of aggregation showed an inverse relationship with baited catches. The distributions of males and females were nearly always positively spatially associated. According to the field data, BTs at the density of 2/ha provide a realistic estimate of the population in the field in the cases of established populations. However, in the periods without population establishment, a denser monitoring trap network is likely required to obtain a reliable estimation of the field population. Full article

The management of Bactrocera oleae (Rossi, 1790) has relied on chemical insecticides, applied as bait or cover sprays. However, concerns over insecticide resistance and environmental impact have driven the search for more effective and eco-friendly alternatives, such as mass trapping. The aim of the study was to assess a novel food-based attractant, derived from Tenebrio molitor Linnaeus, 1758 excreta “Frass”, for its attractiveness to B. oleae adults compared to widely used commercial food-based attractants. Over a four-year period, five field trials were conducted in two organic olive groves in Crete, Greece, using a randomized complete block design with five or six replicate blocks. Results showed that frass-based attractants captured significantly higher number of B. oleae adults than the other tested attractants. Additionally, trap–attractant combinations were assessed to determine the most efficient mass-trapping system. Frass-based attractant deployed in Anel or container traps demonstrated significantly higher attractiveness than all commercial traps and lures tested. The significant advantages of mealworm frass as an attractant highlight its potential to enhance the monitoring and suppression of B. oleae in olive orchards. Its consistent performance, sustainability, and environmental safety make it a promising tool in integrated pest management strategies. Full article

High quality natural zeolites may have insecticidal effects and could be used for pest control. We determined the mineralogical and chemical composition of four representative samples of zeolite-rich rocks (zeot1–zeot4) collected from north-eastern Greece and their oviposition deterrent effect for the olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae). Samples zeot1–zeot4 contain 54–70 wt.% clinoptilolite (HEU-type zeolite) and are free of fibrous minerals. Regarding the chemical composition, samples zeot1–zeot4 contain SiO₂ between 64.29 (zeot4) and 68.03 wt.% (zeot3). The values of the sorption ability ranged from 134 to 195 meq/100 g, and the specific surface area ranged from 6.5 to 8.4 cm²/g. In addition, the concentration of toxic heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn) is very low and within the acceptable limits for the food sector. When females of the olive fruit fly had access to olive fruits treated with aqueous suspensions of zeot1–zeot4, a significant oviposition deterrent effect was observed. The highest oviposition deterrent effect was observed after the application of zeot3 on the olive fruits, i.e., the mean number of eggs laid by 5 females on the treated and non-treated (control) olive fruits after 8 days was 43.1 and 172.3, respectively. Among the tested zeolites, zeot3 had the highest levels of HEU-type zeolite (clinoptilolite), SiO₂, Si, and Ca and the strongest sorption ability and specific surface area. The zeolites oviposition deterrent effect found in our experiments can be attributed to the creation of a thin layer (hymen) of natural zeolite on the surface of the olive fruits which inhibits females landing and egg laying. The oviposition deterrent effect of high-quality Greek zeolites with unique characteristics, if verified with field experiments, could improve the effective control of the olive fruit fly. Full article

Olive fruit fly (Bactrocera oleae) is a pest affecting olive production, causing both qualitative and quantitative damage in all regions of the Mediterranean. This study investigates the spatiotemporal dynamics of olive fruit fly populations obtained from an extensive trap network in five olive-growing regions of Greece—Chalkidiki, Samos, Lesvos, Lasithi, and Chania—over a two-year period (2022–2023). The aim was to understand if and how factors such as variety, temperature, and altitude affect the population of the olive fruit fly. Using Geographical Information System (GIS) tools and spatial analysis, we correlated olive fruit fly numbers with temperature thresholds and altitude categories to analyze different patterns of pest movement. The results show significant variation in population dynamics based on these factors: altitudes, region, and a temperature threshold (at least above 32 °C). These insights are necessary for developing effective and sustainable pest management practices while considering spatial and temporal variability of olive fruit fly movements. Full article

Greece’s olive oil production is significantly affected by the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), and its presence is perceived when it is too late to act for damage recovery. In this work, some unexplored entomopathogenic fungi (EPFs) were studied for their efficacy on olive fruit fly pupae in soil samples. Olive grove soil samples were collected to evaluate the effect of EPFs in their natural environment. The parameters that were analyzed to evaluate the performance of EPFs on B. oleae included the adult survival time, pupa hatch time, and the presence of mycelium on B. oleae pupae and dead adults. The efficacy of some EPFs was highlighted by the mycelium present on dead B. oleae adults after treating pupae with fungal isolates on the soil substrate. The results showed that for the soil substrate, external fungal growth was observed in dead adults with A. contaminans, A. keveii, A. flavus P. lilacinum, and T. annesophieae (100%). Remarkably, the lowest male proportion for soil and non-soil substrates was for A. flavus (0.41–0.42) for the first time, for A. keveii (0.36), and for P. citreosulfuratum (0.41) on the soil-only substrate in contrast to the control treatment (0.5 for both substrates). Given the high infestation caused by the olive fruit flies in Greece, the results of the study emphasize to use of incorporating certain EPF-based biopesticides into integrated pest management (IPM) programs. Full article

The olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae) is regarded as the most harmful pest insect for olive trees worldwide. In order to control olive fruit fly populations and mitigate the damage and economic losses they produce, the development of novel strategies to control the olive fruit fly within an integrated pest management scope has become a major concern. Here we show that a 24-h pre-exposure to the male-specific γ-hexalactone significantly reduces the oviposition on an artificial substrate. The number of eggs per female laid by those females pre-exposed to 1 mg of γ-hexalactone was significantly reduced (6.8 ± 6.1 eggs/female) in comparison to naïve (i.e., non-exposed) females (22.4 ± 10.9 eggs/female), yielding a mean oviposition activity index (OAI) of −0.56 ± 0.22. Contrarily, no significant effect was observed when females were pre-exposed to 0.5 mg of compound, even though the number of eggs per female (14.2 ± 6.3) was lower than that of naïve females, resulting in a mean OIA of −0.24 ± 0.17. Overall, this research represents a preliminary basis for delving into the potential of γ-hexalactone for being used as an oviposition disruptant, albeit further research is still required to address this issue. Full article

The olive fly (Bactrocera oleae, OLF) is a major pest of global significance that occurs in places where olive cultivation thrives. This paper highlights the economic and environmental damage caused by OLF infestations, including reduced olive oil yield and quality, disrupted supply chains, and ecosystem imbalances due to heavy insecticide use. Understanding olive fly ecology is crucial for developing effective control strategies. The review explores the fly’s life cycle, its relationship with olive trees, and how environmental factors like temperature and humidity influence population dynamics. Additionally, studying the role of natural enemies and agricultural practices can pave the way for sustainable control methods that minimize environmental harm. Climate change, intensive cultivation, and the development of resistance to insecticides necessitate a shift towards sustainable practices. This includes exploring alternative control methods like biological control with natural enemies and attract-and-kill strategies. Furthermore, a deeper understanding of OLF ecology, including its response to temperature and its ability to find refuge in diverse landscapes, is critical for predicting outbreaks and implementing effective protection strategies. By employing a holistic approach that integrates ecological knowledge with sustainable control methods, we can ensure the continued viability of olive cultivation, protect the environment, and produce high-quality olive oil. Full article

Bactrocera oleae Rossi causes important agricultural losses in olive growing regions. Despite its economic relevance, the expansion history and biogeography of B. oleae and other olive-feeding fruit flies remain unclear. We used mitogenomic data of Bactrocera species from a broad geographic range to explore possible historical biogeographic patterns in B. oleae and other olive-feeding fruit flies. Our data suggest that (1) the transition from stenophagy on Oleaceae to oligophagy on Olea most likely occurred in Africa more than 6 million years ago (MYA), and (2) the subsequent transition to monophagy on Olea europaea took place in Asia or in Africa in the Early Pleistocene. Our results support equally the hypotheses that the ancestors of modern B. oleae underwent two waves of migration from Asia to Africa or that they zigzagged between Asia and Africa. Full article

In this work, the ability of certain entomopathogenic fungi to control the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), which significantly affects olive cultivation, was assessed. First, entomopathogenic fungi that often contribute to reducing pests, as well as B. oleae, were sought out. Puparia of B. oleae were collected from oil mills, and soil samples were collected from various olive grove regions of Greece. These soils were used as the substrate in which the effect of the entomopathogenic fungi on the B. oleae pupae was studied. In addition, the same treatments were studied in non-soil conditions. The results show that certain known entomopathogenic fungi are able, in their natural environment, to kill B. oleae pupae to a significant extent. The survival time for adults (days) was lower in the presence of Beauveria bassiana (Hypocreales: Cordycipitaceae), at 13.20 in the soil (5.56 ± 0.42) and non-soil (6.76 ± 0.46) conditions, compared to that of the control in soil (9.83 ± 083) and non-soil (9.90 ± 0.72) conditions. This is encouraging for Mediterranean regions where the presence of B. oleae significantly affects olive cultivation, while quality olive oil is in high demand. Full article

A systematic map is a structured method for reviewing and categorizing research evidence on a scientific topic, offering a broad overview without requiring quantitative synthesis. Unlike systematic reviews, which focus on answering specific research questions, systematic maps help identify trends, gaps, and patterns in literature. This approach has gained increasing recognition in entomology, particularly for providing unbiased insights in fields such as medical entomology and insect biodiversity conservation. By mapping existing studies, systematic maps aid in guiding policy decisions and research priorities. This study presents a systematic map of research on olive fruit fly [(Bactrocera oleae) (Rossi) (Diptera: Tephritidae)] control methods, a key pest in olive cultivation. By reviewing literature from the past sixteen years, we aim to provide a comprehensive analysis of the various strategies tested for managing B. oleae. The main objectives are to categorize the types of studies, assess their scope, and identify trends or gaps in pest control research. The results offer a clearer understanding of the current state of knowledge and suggest directions for future research. This systematic map will serve as a valuable resource for entomologists and policymakers working on sustainable pest management strategies. Full article

Traditional and intensive planting systems have paved the way for the phenomenon of intensification, with the super high-density (SHD) system being the most prominent. This system has demonstrated high levels of profitability due to both the reduction in production costs achieved through complete mechanization and a significant increase in olive oil production per hectare, stemming from the more efficient utilization of resources such as light, water, and nutrients. The aim of this study was to evaluate, in a vocated olive-growing area, the phytosanitary status of a SHD olive orchard compared to a traditional one (TRD). The research focused on six key olive pests, considering the interaction between planting systems and eight cultivars in a semi-arid environment. The comparative analysis of pest infestations across the two planting systems revealed significant and complex patterns in pest population distribution and intensity. Overall, the planting system appeared to be the main factor influencing pest dynamics. The SHD olive orchard exhibited the highest infestation levels of Otiorhynchus cribricollis, Palpita unionalis, and Bactrocera oleae. Conversely, in the TRD system, the highest infestation levels of Saissetia oleae, Euphyllura olivina, and Prays oleae were observed. Moreover, the study highlighted a less pronounced effect of cultivars on the prevalence of all monitored key pests. These findings underscore the potential for developing more sustainable and effective pest management strategies tailored to specific planting systems. Furthermore, the results contribute to advancing eco-friendly control approaches and improving pest infestation management practices. Additional research will be necessary to deepen the understanding of these key pests and their interactions within different olive-growing systems. Full article

Agricultural land abandonment is an increasing concern in the EU, especially in Mediterranean regions where traditional perennial crops like olive groves are left unmanaged. This study focuses on the impact of land abandonment on soil-dwelling arthropods in olive groves in Monte Pisano, Tuscany, examining ants, spiders, myriapods, and carabids. Using Generalized Linear Mixed Models, the potential olive fruit fly predator community was analyzed over two sampling periods repeated over two years to assess the effects of both abandonment and its proximity to managed fields. Ants were significantly more abundant in managed fields next to abandoned ones, though there were no differences between managed and abandoned fields. Spider abundance did not respond to abandonment nor proximity. Myriapods were more abundant in abandoned fields during the first sampling period, but the proximity of an abandoned field had no effect. Carabids were more abundant in managed fields, especially those adjacent to other managed fields. These results indicate that arthropod responses to abandonment are taxon-specific, highlighting that a mosaic of managed and abandoned fields can both enhance and reduce olive fruit fly predator abundance. Conservation strategies should integrate varying management intensities to optimize biodiversity in Mediterranean agroecosystems. Future research should investigate long-term effects and specific predator responses to abandonment. Full article

Olive oil production is among the most significant pillars of crop production, especially in the Mediterranean region. The management risks undertaken throughout the olive oil production chain can be minimized using smart tools and applications. This review addressed the influence of the fruit fly of Bactrocera oleae (B. oleae) or Dacus oleae on the quality and antioxidant activity of the olives and their products based on the most recent literature data. Furthermore, in this review, we focused on the latest research achievements in remote sensor systems, features, and monitoring algorithms applied to remotely monitor plant diseases and pests, which are summarized here. Thus, this paper illustrates how precision agriculture technologies can be used to help agricultural decision-makers and to monitor problems associated with integrated pest management for crops and livestock, achieving agricultural sustainability. Moreover, challenges and potential future perspectives for the widespread adoption of these innovative technologies are discussed. Full article

Females of the olive fruit fly Bactrocera oleae use various contact and volatile plant stimuli to find olive fruits and lay their eggs on them. We detected certain volatile organic compounds (VOCs) emitted from the olive fruit and studied their effect on female landings on olive fruits, egg production, and longevity under a series of different temperatures from 15 °C to 35 °C. When female flies were maintained at temperatures from 17 °C to 30 °C and exposed to different fruit VOCs either increased or decreased, depending on the substance tested, their landings on olives, egg production, and longevity. Temperature significantly affected the females’ responses to fruit VOCs. The highest responses of the flies to fruit VOCs were observed at 30 °C, except for longevity. By contrast, at 15 °C or 35 °C, the flies did not show any response to VOCs. Our results may contribute to a better understanding of the olive fly positive or negative responses to fruit VOCs and the improvement of its control. Full article