Search Results (48)

Biological control using parasitoid wasps and the sterile insect technique (SIT) are environmentally sustainable strategies that can be integrated into fruit fly management programs. Both eco-friendly techniques have been applied independently against the invasive pest Ceratitis capitata (Wiedemann), commonly known as the Mediterranean fruit fly or medfly, in irrigated fruit-growing areas of San Juan Province, central-western Argentina. At the San Juan Biofactory, both sterile medfly males and the exotic larval parasitoid Diachasmimorpha longicaudata (Ashmead) are mass-reared using the Vienna-8 temperature-sensitive lethal (tsl) genetic sexing strain. The aim of this study was to assess the effectiveness of controlling the medfly by combining releases of D. longicaudata and sterile male flies under field cage (semi-field) conditions. Trials were conducted during the summer, from 31 January to 26 April 2019, at a fruit farm in the Rawson district of San Juan. Each mesh-covered cylindrical iron field cage enclosed five exposure devices, each holding three semi-ripe figs used as oviposition substrates. The experimental treatments were as follows: (1) control (no parasitoid or sterile fly releases), (2) parasitoid release alone (fertile flies from a biparental medfly strain which were released first, followed by parasitoids), (3) sterile medfly release alone (fertile flies and sterile males released simultaneously), and (4) combined techniques (fertile and sterile medflies released first, followed by parasitoids). The resulting dataset includes the number of recovered puparia and non-hatching puparia, adult flies and parasitoids, as well as the benefit proportion and Abbott’s effectiveness for each experimental condition. Combining both methods produced an additive suppression of the pest population, achieving 96% suppression of the medfly population, a value close to a near-eradication effect. These results support the use of both control techniques in an area-wide integrated medfly management approach. Full article

The Mediterranean fruit fly (Ceratitis capitata) is a globally invasive pest that affects a wide range of fruit and vegetable crops. Identifying cost-effective attractants is essential for sustainable integrated pest management (IPM). This study explored whether molecular docking, combined with electrophysiological recordings, can help prioritize structurally diverse compounds with potential relevance to medfly olfaction. We assessed the predicted interactions of more than 100 attractant-related and semiochemical compounds, including multiple stereoisomers, with 14 odorant-binding proteins (OBPs) and four odorant receptors (ORs). Trimedlure served as a benchmark ligand. Docking suggested that several sesquiterpenes may interact favorably with subsets of OBPs and ORs, although these predictions require biochemical validation. A small set of compounds with high predicted affinity, readily available in the laboratory, was further examined using electroantennography (EAG), which confirmed that selected sesquiterpenes elicited peripheral antennal activation in irradiated males. Overall, our results demonstrate the utility of computational screening as an exploratory tool for prioritizing candidate ligands and generating hypotheses about chemosensory processing in C. capitata. Integrating molecular modeling with biochemical and behavioral validation is a promising approach to developing next-generation IPM attractants. Full article

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is considered one of the most important phytophagous pests worldwide. In Croatia, it severely affects the fresh fruit production in Dalmatia, and a national suppression action plan has been established to alleviate farmers’ burden. The aim of the current paper was to comprehensively study the overwintering dynamics of medfly in Dalmatia and investigate whether adults and pupae in addition to larvae can overwinter in different conditions, with a goal to support the establishment of a sound off-season control strategy against this pest. The off-season strategy, which was recently proposed in the frameworks of the EU Horizon 2020 funded project FF-IPM, focuses on the management of the low adult populations during winter and early spring period that has a detrimental effect on the development of the on-season summer and early autumn populations. Overwintering trials were conducted in Split (Dalmatia region, Croatia) using the local C. capitata population. Cages with different life stages (adults, pupae) or infested fruits were periodically transferred in three overwintering sites (open-field, semi-field, and urban conditions) from October to December (two to three establishment dates during the 2019–2020 and 2020–2021 season). Our results provide strong evidence that, in addition to larvae within fruit, both adult and pupae can survive in significant proportions in open-field and urban conditions. Overwintering site and establishment date were both significant predictors of the overwintering success of adults, and they affect pupae developmental duration, adult emergence rates from overwintering pupae, female fecundity, and generally the overwintering ability of the pupae. Our results suggest that the current national strategy for C. capitata suppression, which is based on the assumptions of larvae overwintering need to be adjusted by development and implementation of the off-season strategy. Full article

Ceratitis capitata (Wiedemann) or medfly is a polyphagous pest of fruit crops worldwide. The Asian-native larval parasitoid Diachasmimorpha longicaudata (Ashmead) is mass-reared at the San Juan Biofactory and is currently released for medfly control in Argentina. Information on parasitoid survival, reproduction, and population growth parameters is critical for optimizing the mass-rearing process and successfully achieving large-scale release. This study provides a first-time insight into the demography of two population lines of D. longicaudata: one mass-reared on medfly larvae of the Vienna-8 temperature-sensitive lethal genetic sexing strain and the other on larvae of the wild biparental medfly strain. The aim was to compare both parasitoid populations to improve mass-rearing quality and to assess performance on medfly in a semi-arid environment, typical of Argentina’s central-western fruit-growing region. Tests were performed under laboratory and non-controlled environmental conditions in semi-field cages during three seasons. Dl_(Cc-bip) females exhibited higher reproductive potential than did Dl_(Cc-tsl) females under lab conditions. However, both Dl_(Cc-bip) and Dl_(Cc-tsl) were found to be similar high-quality females with high population growth rates in warm–temperate seasons, i.e., late spring and summer. Dl_(Cc-bip) females were only able to sustain low reproductive rates in early autumn, a colder season. These results are useful for improving the parasitoid mass production at the San Juan Biofactory and redesigning parasitoid release schedules in Argentina’s irrigated, semi-arid, fruit-growing regions. Full article

The Sterile Insect Technique (SIT) is most effective at large regional scales when applied within an area-wide framework. However, there is a need to investigate its feasibility at smaller scales, e.g., for emergency responses to local fruit fly invasions or planning for preventive release of sterile males in local high-risk zones. Available decision support tools and SIT implementation models are effective for large-scale interventions but tend to ignore the influences of fine-grained terrain structures and therefore offer little guidance for small-scale SIT operations in locally diverse landscapes. This study addresses this issue by adapting a site-specific individual-based PESTonFARM model to simulate both the behaviour and fate of individual members of ultra-small invasive medfly propagules and the post-release dispersal and mating performance of sterile males in heterogeneous and mosaic landscapes. To illustrate model operation, several SIT implementation scenarios were simulated to reveal the influence of local landscape structure on the behaviour of wild and released sterile males and to quantitatively assess the effectiveness of different SIT scenarios. Our results demonstrate the sensitivity of the model and showed that the influence of the spatiotemporal structure of local resources should not be ignored when planning local SIT operations. Full article

This study evaluates the potential of quantum dots (QDs) as a marking method for Mediterranean fruit flies (Ceratitis capitata) (Medfly) in comparison to traditional fluorescent powder. As a highly destructive pest impacting a wide variety of fruit crops, an effective marking technique is essential for improving the biological understanding and management of Medflies, including control strategies like the Sterile Insect Technique (SIT). Through multiple controlled experiments, we examined the effects of QDs and fluorescent powder markers on Medfly flight ability, marker retention rates, and marker durability and stability under diverse storage conditions. Fluorescent powder demonstrated consistently high reliability across all parameters, whereas QDs showed reduced retention, particularly when applied to pupae, and had a more pronounced negative effect on flight ability. This was illustrated by the field trials, which did not recapture any of the QD-marked flies, highlighting the current limitations in QD application methods. Additionally, fluorescent powders outperformed QDs in both long-term storage conditions and short-term stability tests. These findings indicate that while QDs possess potential as marking agents, further refinement of application techniques is required to achieve comparable efficacy to fluorescent powders in pest management contexts. Full article

The essential oil (EO) of Schinus areira exhibits a chemical composition dominated by monoterpene and sesquiterpene hydrocarbons, with α-phellandrene, limonene, α-pinene, and p-cymene as major constituents. This study aimed to evaluate the effects of S. areira EO on the biology and behavior of the Mediterranean fruit fly, Ceratitis capitata, particularly its attraction to the EO and the impact on its reproductive behavior and survival. Females were attracted at the initial choice and the time spent in the arm of the Y-tube olfactometer with the EO was longer, while males were attracted at the final choice, indicating the attractive potential of S. areira EO for both sexes of C. capitata. Within the context of the sterile insect technique (SIT), the better performance of released sterile males allows more copulations with wild females in competition with wild males, increasing the efficacy of the SIT. Exposure of tsl sterile males to the EO did not enhance their sexual competitiveness and increased latency to initiate copulation, indicating potential adverse effects. In addition, in oviposition assays, only a low concentration of the EO stimulated egg-laying on treated substrates, possibly due to the absence of deterrent compounds such as linalool. Finally, the LD50 of the EO was <25 µg/fly for both females and males, at 72 h post-treatment. These findings highlight the potential of EOs as biopesticides that influence the behaviors of C. capitata and emphasize the need for further studies to optimize their application in integrated pest management strategies, including the SIT. Full article

Temperature and host fruit availability are key factors influencing the life history traits of the Mediterranean fruit fly (medfly) (Ceratitis capitata). This study examines how developmental temperature and host fruit type affect adult longevity and fecundity in medflies from six populations spanning Southern to Central Europe. Larvae were reared on apples and bitter oranges at three constant temperatures (15, 20, and 25 °C), with pupae maintained under the same thermal conditions until adult emergence. Adults were then kept at 25 °C, with longevity and fecundity recorded daily. The results showed that higher developmental temperatures increased adult lifespan across all populations, regardless of host fruit. Similarly, fecundity rates in ovipositing females were higher at higher temperatures. Reproductive periods (pre-oviposition, oviposition, and post-oviposition) varied among populations, indicating population-specific responses. These findings underscore how temperature and host fruit availability shape medfly invasion dynamics, highlighting the species’ biological plasticity and adaptation to different environments. This research provides valuable insights for pest management, particularly in the context of climate change, offering strategies to mitigate the spread of medflies into new regions. Full article

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann 1824; Diptera, Tephritidae), is considered one of the most important pests, infesting more than 300 species of fresh fruit and vegetables worldwide. The medfly is an important invasive species, which has spread from the eastern part of sub-Saharan Africa to all of the world’s continents in recent centuries. Currently, the medfly is expanding its geographical range to cooler, temperate areas of the world, including northern areas of Mediterranean countries and continental areas of Central Europe. We collected and analysed all the available information, including in historical records, on the phenology of the medfly in the Balkan Peninsula, to map and understand the path of invasion and spread dynamics on the northern Mediterranean coast and in Central Europe. The medfly was first recorded in the Balkan Peninsula in 1915, in the Aegean area on the island of Aigina, followed by a few records on its presence in the Peloponnese in the early 1930s and throughout the Adriatic coastal area in the 1950s; it was first detected on the Croatian coast in 1947. By 2010, the medfly had been detected along the entire Ionian coast, while the first record of its presence on the Balkan coast of the Black Sea was made in 2005. Since 2000 to date, there has been a significant increase in the frequency of medfly detections in the interior of the Balkan Peninsula, including occasional detections in areas with unfavourable climatic conditions for overwintering, which seems to be favourable for reproduction during the summer and lead to significant infestation of late ripening fruits (late summer and autumn). In the last 20 years, the medfly has spread to more northerly areas (43 to 45 degrees latitude) and has been detected at higher altitudes (>200 to 600 m). Along the Balkan Peninsula, the infestation of fruits from 25 host plant species, from 14 genera and 10 plant families, has been reported. Considering the extremely high invasiveness of the medfly and its wide distribution in several Balkan regions with different climatic conditions, we can assume that it is adapting to new climatic conditions and infesting new host plants. Full article

Ceratitis capitata (Wiedemann) (medfly) strongly affects Argentinean fruit production and export. Augmentative biological control using the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) is currently applied to this problem. The ability to find and parasitize medfly larvae on a wide diversity of fruit host species is a key issue that needs to be analyzed. This research assessed the effect of the physical features of fruit on the preference of foraging D. longicaudata females and the influence of varying release density on parasitoid performance as a pest mortality factor in three fruit species. Trials were performed inside field cages under semi-arid environmental conditions in Argentina’s central-western fruit-growing region. Sweet orange, peach, and fig were tested. The fruits were inoculated with third-instar larvae of the Vienna-8 temperature-sensitive lethal medfly strain. Naïve, 5 d-old mated D. longicaudata females were released in cages at 20, 40, 80, and 160 parasitoid densities. The highest levels of medfly mortality and parasitoid emergence were recorded in fig and peach, although D. longicaudata also induced mortality in orange, a fruit with few physical features favorable to parasitism. The medfly mortality in all fruit host species significantly increased with an increased number of parasitoid females released into the field cages. Diachsmimorpha longicaudata has high potential as a medfly biocontrol agent. Full article

Invasive Tephritid fruit flies rank among the most destructive agricultural and horticultural pests worldwide. Heat treatment is commonly employed as a post-harvest method to exterminate fruit flies in fruits or vegetables. These pest species exhibit distinct tolerance to heat treatments, suggesting that the molecular pathways affected by heat may differ among species. In this study, the Queensland fruit fly (Qfly), Bactrocera tryoni, was utilised as a model investigate its molecular response to heat stress through heat bioassays. RNA samples from flies before and after heat treatment were extracted and sequenced to identify genes with significant changes in expression. These findings were compared to another serious Tephritid fruit fly species, the Mediterranean fruit fly (Medfly), Ceratitis capitata, under similar heat treatment conditions. The analysis reveals only three common genes: heat shock protein 70 (HSP70), HSP68, and 14-3-3 zeta protein. However, despite these shared genes, their expression patterns differ between Qfly and Medfly. This suggests that these genes might play different roles in the heat responses of each species and could be regulated differently. This study presents the first evidence of differing molecular responses to heat between Qfly and Medfly, potentially linked to their varied origins, habitats, and genetic backgrounds. These findings offer new insights into Tephritid fruit fly responses to heat at the molecular level, which may help refine post-harvest strategies to control these pests in the future. Full article

Ceratitis capitata, known as the Mediterranean fruit fly (Medfly), is a major dipteran pest significantly impacting fruit and vegetable farming. Currently, its control heavily relies mainly on chemical insecticides, which pose health risks and have effects on pollinators. A more sustainable and species-specific alternative strategy may be based on double-stranded RNA (dsRNA) delivery through feeding to disrupt essential functions in pest insects, which is poorly reported in dipteran species. Previous reports in Orthoptera and Coleoptera species suggested that dsRNA degradation by specific nucleases in the intestinal lumen is among the major obstacles to feeding-mediated RNAi in insects. In our study, we experimented with three-day adult feeding using a combination of dsRNA molecules that target the expression of the ATPase vital gene and two intestinal dsRNA nucleases. These dsRNA molecules were recently tested separately in two Tephritidae species, showing limited effectiveness. In contrast, by simultaneously feeding dsRNA against the CcVha68-1, CcdsRNase1, and CcdsRNase2 genes, we observed 79% mortality over seven days, which was associated with a decrease in mRNA levels of the three targeted genes. As expected, we also observed a reduction in dsRNA degradation following RNAi against nucleases. This research illustrates the potential of utilizing molecules as pesticides to achieve mortality rates in Medfly adults by targeting crucial genes and intestinal nucleases. Furthermore, it underscores the importance of exploring RNAi-based approaches for pest management. Full article

The Mediterranean fruit fly (medfly), Ceratitis capitata, is considered one of the most destructive fruit pests worldwide. Female medflies prefer to lay eggs in ripening, ripe, or overripe fruits. In deciduous orchards of temperate regions, fruitlets (juvenile fruits) of early cultivars could represent the earliest spring resource with a potential host function for medflies. However, little is known about the medfly female’s ability to ovipositing and complete breeding in fruitlets. To clarify the possible role of fruitlets, the suitability of key-host fruitlets for the oviposition of medflies and the further development of immature stages were examined in laboratory conditions and an attempt was made to assess the degree of infection of fruitlets collected in the field. Additionally, the development of the overwintering medfly population and the putative use of fruitlets as a resource for early population growth were simulated using the PESTonFARM model optimized to reflect specific features of medfly biology and behavior. Our laboratory data demonstrate that nectarine and pear fruitlets can support the full development of medfly offspring. However, no medfly pupae were obtained from a sample of 14,000 fruitlets collected at the farm. The simulation showed that the sample number needed to detect with at least 95% certainty rare cases of medfly pupae or adults emerging from infected fruitlets is several tens of thousands, which is several times more than the actual number of fruitlets used in our study. Our research suggests that the fruitlets of some cultivated fruit species can potentially constitute a viable food resource for the development of the earliest generation of spring medflies, with implications for medfly Integrated Pest Management (IPM). Full article

Understanding the seasonal dynamics inherent to non-crop host–fruit fly–parasitoid interactions is vitally important for implementing eco-friendly pest control strategies. This study assessed the abundance and seasonal infestation levels of three pest fly species, Ceratitis capitata (Wiedemann), Anastrepha fraterculus (Wiedemann), Drosophila suzukii (Matsumura), as well as the related saprophytic drosophilids, and their natural parasitism in a disturbed wild habitat characterized by non-crop hosts in northwestern Argentina over 40 months. Juglans australis Griseb (walnut), Citrus aurantium L. (sour orange), Eriobotrya japonica (Thunb.) Lindley (loquat), Prunus persica (L.) Batsch (peach), and Psydium guajava L. (guava) were sampled throughout their fruiting seasons. Fruits were collected from both the tree canopies and the ground. The most abundant puparia was A. fraterculus, followed by C. capitata and D. suzukii. Drosophila species from the D. melanogaster group were highly abundant only in fallen fruits. Spatiotemporal overlaps of different host fruit availability provided suitable sources for pest proliferation throughout the year. The populations of both invasive pests peaked from December to January, and were related to the highest ripe peach availability, whereas the A. fraterculus population peaked from February to April, overlapping with the guava fruiting period. The three pest fly species were parasitized mainly by three generalist resident parasitoids, which are potential biocontrol agents to use within an integrated pest management approach. Full article

The α6 subunit of the nicotinic acetylcholine receptor (nAChR) has been proposed as the target for spinosad in insects. Point mutations that result in premature stop codons in the α6 gene of Ceratitis capitata flies have been previously associated with spinosad resistance, but it is unknown if these transcripts are translated and if so, what is the location of the putative truncated proteins. In this work, we produced a specific antibody against C. capitata α6 (Ccα6) and validated it by ELISA, Western blotting and immunofluorescence assays in brain tissues. The antibody detects both wild-type and truncated forms of Ccα6 in vivo, and the protein is located in the cell membrane of the brain of wild-type spinosad sensitive flies. On the contrary, the shortened transcripts present in resistant flies generate putative truncated proteins that, for the most part, fail to reach their final destination in the membrane of the cells and remain in the cytoplasm. The differences observed in the locations of wild-type and truncated α6 proteins are proposed to determine the susceptibility or resistance to spinosad. Full article