Cherry Fruit Fly Rhagoletis Cerasi Research Articles

Parallel Sequencing of Wolbachia wCer2 from Donor and Novel Hosts Reveals Multiple Incompatibility Factors and Genome Stability after Host Transfers.

The application of Wolbachia in insect pest and vector control requires the establishment of genotypically stable host associations. The cytoplasmic incompatibility (CI) inducing Wolbachia strain wCer2 naturally occurs in the cherry fruit fly Rhagoletis cerasi as co-infection with other strains and was transferred to other fruit fly species by embryonic microinjections. We obtained wCer2 genome data from its native and three novel hosts, Drosophila simulans, Drosophila melanogaster, and Ceratitis capitata and assessed its genome stability, characteristics, and CI factor (cif) genes. De novo assembly was successful from Wolbachia cell-enriched singly infected D. simulans embryos, with minimal host and other bacterial genome traces. The low yield of Wolbachia sequence reads from total genomic extracts of one multiply infected R. cerasi pupa and one singly infected C. capitata adult limited de novo assemblies but was sufficient for comparative analyses. Across hosts wCer2 was stable in genome synteny and content. Polymorphic nucleotide sites were found in wCer2 of each host; however, only one nucleotide was different between R. cerasi and C. capitata, and none between replicated D. simulans lines. The wCer2 genome is highly similar to wAu (D. simulans), wMel (D. melanogaster), and wRec (Drosophila recens). In contrast to wMel and wRec (each with one cif gene pair) and wAu (without any cif genes), wCer2 has three pairs of Type I cif genes, and one Type V cifB gene without a cifA complement. This may explain previously reported CI patterns of wCer2, including incomplete rescue of its own CI modification in three novel host species.

Prospects of using environmentally friendly methods in the system of integrated cherry protection from the European cherry fruit fly Rhagoletis cerasi L.

Prospects of using environmentally friendly methods in the system of integrated cherry protection from the European cherry fruit fly Rhagoletis cerasi L.

Laboratory and field trials to identify effective chemical control strategies for integrated management of Drosophila suzukii in European cherry orchards

The recent spread of the Spotted Wing Drosophila (SWD), Drosophila suzukii, in Europe has created considerable concern because of the damage recorded on various crops, in particular on sweet cherry, despite the use of conventional pesticides. Effective chemical control strategies are urgently required to improve integrated SWD management. Insecticide use should be incorporated in an IPM strategy that adopts cultural and biological control methods and tools to ensure high protection of cherry production while fulfilling export market requirements. Laboratory and field trials were conducted in North-Eastern Italy to identify the most effective and sustainable insecticides to be used against SWD in cherry orchards. In the laboratory, cherries previously infested by SWD were dipped in insecticide solutions to assess their effectiveness in controlling eggs and larvae. In other laboratory trials cherries were first treated with insecticides and then exposed to adults to assess residual activity. A number of chemical control strategies (including one designed for organic orchards) were then compared in cherry orchards. These strategies were planned also considering the need to control the European cherry fruit fly Rhagoletis cerasi L., a key pest of cherry in Europe and elsewhere. A number of formulations based on cyantraniliprole, spinosad, spinetoram, phosmet, lambda-cyhalothrin and deltamethrin were effective against different life stages of SWD in the laboratory. SWD control in the field was influenced by the use of above-mentioned insecticides and the number of applications during the cherry ripening period. Insecticides selected for the protection of organic cherry orchards were almost ineffective. Some strategies defined for conventional orchards were also effective against R. cerasi. In most cases (dimethoate was the exception) insecticide residues were lower than maximum residue limits required by the European Union to export cherries to major markets. In conditions of high pest pressure, three to four applications with active ingredients having different modes of action were needed to keep D. suzukii and R. cerasi damage beneath economic thresholds. Sanitation and harvest management could be helpful in lowering pesticide use. A number of tactics such as insect-proof nets, biological and cultural methods should be incorporated for an effective IPM strategy with benefits not only for human and environmental health but also in terms of the lifetime of currently effective insecticides.

The hitchhiker's guide to Europe: the infection dynamics of an ongoing Wolbachia invasion and mitochondrial selective sweep in Rhagoletis cerasi.

Wolbachia is a maternally inherited and ubiquitous endosymbiont of insects. It can hijack host reproduction by manipulations such as cytoplasmic incompatibility (CI) to enhance vertical transmission. Horizontal transmission of Wolbachia can also result in the colonization of new mitochondrial lineages. In this study, we present a 15‐year‐long survey of Wolbachia in the cherry fruit fly Rhagoletis cerasi across Europe and the spatiotemporal distribution of two prevalent strains, wCer1 and wCer2, and associated mitochondrial haplotypes in Germany. Across most of Europe, populations consisted of either 100% singly (wCer1) infected individuals with haplotype HT1, or 100% doubly (wCer1&2) infected individuals with haplotype HT2, differentiated only by a single nucleotide polymorphism. In central Germany, singly infected populations were surrounded by transitional populations, consisting of both singly and doubly infected individuals, sandwiched between populations fixed for wCer1&2. Populations with fixed infection status showed perfect association of infection and mitochondria, suggesting a recent CI‐driven selective sweep of wCer2 linked with HT2. Spatial analysis revealed a range expansion for wCer2 and a large transition zone in which wCer2 splashes appeared to coalesce into doubly infected populations. Unexpectedly, the transition zone contained a large proportion (22%) of wCer1&2 individuals with HT1, suggesting frequent intraspecific horizontal transmission. However, this horizontal transmission did not break the strict association between infection types and haplotypes in populations outside the transition zone, suggesting that this horizontally acquired Wolbachia infection may be transient. Our study provides new insights into the rarely studied Wolbachia invasion dynamics in field populations.

Evaluation of native entomopathogenic nematodes for the control of the European cherry fruit fly Rhagoletis cerasi L. (Diptera: Tephritidae) larvae in soil

Turkey is the world's largest producer of sweet cherries. The European cherry fruit fly, Rhagoletis cerasi L. (Diptera: Tephritidae), is a major pest of sweet cherry crops in Europe and Turkey. The detection of only one larva in the fruit by the processor can result in the rejection of the entire crop of that orchard and/or farm as \wormy and unmarketable. The main control tactic for R. cerasi is to prevent the females from laying eggs in the fruit. Currently, only a few insecticides are being used, and their application is debatable due to problems with residual ecotoxicity for humans and beneficial organisms. As an alternative to using insecticides for the reduction of adult populations, 4 indigenous entomopathogenic nematode species, Steinernema carpocapsae (Anamur isolate), S. feltiae (Rize isolate), Heterorhabditis bacteriophora (Ekecik isolate), and H. marelatus (Ankara isolate), were bioassayed against last-instar R. cerasi larvae at different temperatures (10, 15, and 25 °C) and nematode concentrations (0, 100, 500, and 1000 IJs/larva). Temperature and nematode concentration had a significant effect on the efficacy of nematode species. S. feltiae was the most virulent species at all temperatures and nematode concentrations. Only S. feltiae showed higher than 40% mortality at low temperatures (10 and 15 °C). At 25 °C, S. feltiae caused 95% mortality, followed by H. marelatus (82%) and H. bacteriophora (76%), at 1000 IJs/larva concentration. Our results indicate that R. cerasi larvae are highly susceptible to entomopathogenic nematode infection. In particular, S. feltiae has high potential for reducing last-instar larval populations, thus decreasing the adult population in the spring.

Dispersal of Rhagoletis cerasi in Commercial Cherry Orchards: Efficacy of Soil Covering Nets for Cherry Fruit Fly Control.

Demand for organic cherries offers producers a premium price to improve their commercial viability. Organic standards require that producers find alternatives to pesticides. Soil treatments to control the European cherry fruit fly Rhagoletis cerasi (L.) (Diptera: Tephrididae) appear to be an attractive option. However, soil treatments can only be effective if the migration of flies is low, because mature flies may migrate from near-by trees for oviposition. To examine the general potential of soil treatments and to understand the dispersal and flight behaviour of R. cerasi within orchards, experiments using netting to cover the soil were conducted in two orchards with different pest pressure during two years. The netting reduced flight activity by 77% and fruit infestation by 91%. The data showed that the flies have a dispersal of less than 5 m within orchards, which is very low. The low thresholds for tolerance for infested fruit in the fresh market creates a strong economic incentive for control, therefore, soil covering is a promising strategy for controlling R. cerasi in commercial orchards.

Integrated Management of European Cherry Fruit Fly Rhagoletis cerasi (L.): Situation in Switzerland and Europe.

The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is a highly destructive pest. The low tolerance for damaged fruit requires preventive insecticide treatments for a marketable crop. The phase-out of old insecticides threatens cherry production throughout the European Union (EU). Consequently, new management techniques and tools are needed. With the increasing number of dwarf tree orchards covered against rain to avoid fruit splitting, crop netting has become a viable, cost-effective method of cherry fruit fly control. Recently, a biocontrol method using the entomopathogenic fungus Beauveria bassiana has been developed for organic agriculture. However, for most situations, there is still a lack of efficient and environmentally sound insecticides to control this pest. This review summarizes the literature from over one hundred years of research on R. cerasi with focus on the biology and history of cherry fruit fly control as well as on antagonists and potential biocontrol organisms. We will present the situation of cherry fruit fly regulation in different European countries, give recommendations for cherry fruit fly control, show gaps in knowledge and identify future research opportunities.

Transinfection of the olive fruit fly Bactrocera oleae with Wolbachia: towards a symbiont-based population control strategy

The olive fruit fly Bactrocera oleae is responsible for worldwide economic damage. In this report, we describe the first B. oleae lines transinfected with the Wolbachia strain wCer2, an endosymbiont of the cherry fruit fly Rhagoletis cerasi. Immunostaining followed by confocal microscopy, detects high numbers of Wolbachia in embryos as well as in ovarioles and sperm from individuals of both transinfected lines. wCer2 was uniformly distributed in B. oleae egg chambers and the cortex of preblastoderm embryos. Wolbachia is known to manipulate host reproduction with several strategies, one of which is cytoplasmic incompatibility (CI), resulting in embryonic mortality in incompatible crosses. Wolbachia was found to induce complete CI in the novel host, suggesting that symbiont-based approaches can be used as novel environmentally friendly tools for the control of natural olive fruit fly populations.

Field applications of Beauveria bassiana to control the European cherry fruit fly Rhagoletis cerasi

AbstractField experiments with foliar applications of Beauveria bassiana ATCC 74040 (product Naturalis‐L) were conducted to control the European cherry fruit fly Rhagoletis cerasi Loew (Diptera: Tephritidae), a major pest of cherries in Europe. Naturalis‐L was applied at concentrations of 250 ml per 100 l in 7‐day intervals during the flight period of R. cerasi. Flight activity monitored by yellow sticky traps was only slightly affected by treatments. Infection and mycosis of adult cherry fruit flies was shown to be possible under field conditions. Fruit infestation was assessed at harvest. The number of infested fruits was significantly reduced by 65% with foliar applications of Naturalis‐L. These results were obtained from five experiments in 2 years with considerably different weather conditions (wet vs. dry) and in different orchards with different flight intensities of R. cerasi (low vs. high) and different cherry varieties (early ripening vs. late ripening). In conclusion, the application of Naturalis‐L is a suitable and economically feasible strategy for controlling R. cerasi in organic cherry production. The product Naturalis‐L is currently registered for cherry fruit fly control in Italy and Switzerland.

Physiological and biological patterns of a highland and a coastal population of the European cherry fruit fly during diapause

Adult emergence of univoltine temperate insect species and its synchronization with specific host phenological stages is mainly regulated by obligatory pupal diapause. Although a few studies have investigated the factors affecting diapause intensity, little attention has been paid to the physiological alterations and metabolic regulation that take place during diapause. Here, we describe differences in diapause between a highland and a coastal Greek population of the European cherry fruit fly Rhagoletis cerasi, a major pest of sweet and sour cherries in many European countries. Pupae of both populations were exposed to the environmental conditions prevailing in the two areas and diapause termination was observed under laboratory conditions. The regulation of energetic metabolites during the long pupae stage was examined under both field and laboratory conditions. Differences in diapause intensity revealed that the two populations have adapted to the local geographical and climatic conditions and have different requirements for low temperatures to terminate diapause. The coastal population undergoes a shorter diapause and adults emerge more rapidly, especially in the highland area. The highland population failed to terminate diapause (<40% adult emergence) in the coastal area. Both populations draw on their major energetic reserves (lipids and protein) similarly during diapause. Nevertheless, regulation of carbohydrate and glycogen reserves seems to vary between the populations: major peaks of these stored nutrients occur on different dates in the two populations, suggesting a differential regulation. Differences in diapause intensity imply a genetic differentiation between the two populations. The importance of our findings in understanding the physiological patterns during obligatory diapause of a univoltine insect species, as well as the practical implications for the development of specific phenological models for the European cherry fruit fly are discussed.

HiddenWolbachiadiversity in field populations of the European cherry fruit fly,Rhagoletis cerasi(Diptera, Tephritidae)

The European cherry fruit fly Rhagoletis cerasi has been a field model for cytoplasmic incompatibility since the mid 1970s. Two Wolbachia strains were detected in this tephritid species and wCer2 was described as the CI inducing agent dividing European populations into two unidirectional incompatible groups, i.e. southern females produce viable offspring with northern males, whereas the reciprocal cross results in incompatibility. We detected three new Wolbachia strains by sequencing a multitude of plasmids derived from Wolbachia surface protein gene (wsp) polymerase chain reaction (PCR) products. Strain-specific primers were developed allowing individual diagnosis without need for cloning. Hybridization of specific PCR products with a wsp oligonucleotide enhanced the detection limit significantly and revealed the presence of low-titre infections in some strains, in different ontogenetic stages and in adults of different age. We then performed a survey of strain prevalence and infection frequency in eight European regions. wCer1 was fixed in all populations, whereas wCer2 was detected only in the South. wCer3 frequency was the lowest without a clear distribution pattern. The abundance of wCer4 was homogenous across Europe. Like wCer2, wCer5 showed significant differences in spatial distribution. Our new findings of previously undetected and recombinant Wolbachia strains in R. cerasi reveal a major caveat to the research community not to overlook hidden Wolbachia diversity in field populations. Low-titres and geographical variability in Wolbachia diversity are expected to influence the outcome of Wolbachia population dynamics and Wolbachia-based insect population control and may create invasion barriers for expanding and artificially introduced Wolbachia strains.

Wolbachia-induced cytoplasmic incompatibility as a means for insect pest population control.

Biological control is the purposeful introduction of parasites, predators, and pathogens to reduce or suppress pest populations. Wolbachia are inherited bacteria of arthropods that have recently attracted attention for their potential as new biocontrol agents. Wolbachia manipulate host reproduction by using several strategies, one of which is cytoplasmic incompatibility (CI) [Stouthamer, R., Breeuwer, J. A. J. & Hurst, G. D. D. (1999) Annu. Rev. Microbiol. 53, 71-102]. We established Wolbachia-infected lines of the medfly Ceratitis capitata using the infected cherry fruit fly Rhagoletis cerasi as donor. Wolbachia induced complete CI in the novel host. Laboratory cage populations were completely suppressed by single releases of infected males, suggesting that Wolbachia-induced CI could be used as a novel environmentally friendly tool for the control of medfly populations. The results also encourage the introduction of Wolbachia into pest and vector species of economic and hygenic relevance to suppress or modify natural populations.

Catalytic Glycosylation with Rhodium(III)‐Triphos Catalysts.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Catalytic Glycosylation with Rhodium(III)-Triphos Catalysts

The formation of glycosides in high yield from 1-hydroxy sugars using catalytic amounts (0.5mol%) of Rh(III)Cl3(triphos) (1a) or [Rh(III)(MeCN)3(triphos)](TfO)3 (1b) is described. High stereocontrol at the anomeric center is achieved by neighboring group participation. In addition, an application of this new glycosylation procedure for the synthesis of a derivative of the oviposition-deterring pheromone of the cherry fruit fly Rhagoletis cerasi is presented.

Wolbachia infections and superinfections in cytoplasmically incompatible populations of the European cherry fruit fly Rhagoletis cerasi (Diptera, Tephritidae).

Wolbachia is an obligately intracellular, maternally inherited bacterium which has been detected in many arthropods. Wolbachia infections disperse in host populations by mechanisms such as cytoplasmic incompatibility (CI). CI leads to embryonic mortality which occurs when infected males mate with uninfected females or females with a different Wolbachia strain. Populations of the European cherry fruit fly Rhagoletis cerasi (Diptera, Tephritidae) were found to be infected by two different Wolbachia strains, wCer1 and wCer2. Superinfections with both strains occurred throughout southern and central Europe and infections with wCer1 were found in northern, western and eastern Europe. Strong unidirectional CI between European populations of R. cerasi were first reported in the 1970s. From the conformity in the recent geographical distribution of the Wolbachia infections and the CI expression patterns found 25 years ago it was deduced that wCer2 potentially causes CI in R. cerasi. The comparison of the geographical distributions indicated that wCer1 + 2 must have spread into wCer1-infected populations in some areas. In other regions, a spread of wCer1 + 2 was probably prevented by dispersal barriers. There, a sharp transition from infected to superinfected populations suggested regional isolation between wCer1 and wCer1 + 2-infected populations.

Evaluation of trap types and food attractants for Rhagoletis cerasi (Diptera: Tephritidae).

Trapping experiments were conducted during the period of flight activity of the cherry fruit fly Rhagoletis cerasi L. in the area of Thessaloniki, northern Greece, during the years 1993-1997 to test several traps alone and in combination with different food attractants. Yellow sticky-coated visual traps were more effective than McPhail-type traps baited with different food attractants. Of the visual traps, the most effective was the yellow Rebell trap. The Rebell trap, provided with a dispenser containing a slow release formulation of ammonium acetate attached to the lower part of the trap, was found to be the most effective of all treatments tested, capturing approximately 50% more R. cerasi flies than the Rebell trap without any attractant. Ammonium carbonate dispensers did not increase the performance of Rebell traps. More mature females were captured in Rebell traps baited with or without ammonium acetate than in McPhail-type traps baited with ammonium acetate. This study demonstrates that Rebell traps baited with an ammonium acetate dispenser can provide a more effective tool for monitoring and mass trapping of R. cerasi than the currently used unbaited Rebell traps.

Pheromone synthesis, CLX. A new synthesis of the oviposition-deterring pheromone of the European cherry fruit flyRhagoletis cerasi L.

A new synthesis of the ammonium salt 1c of (8RS,15R)-N-[(β-D-glucopyranosyloxy)-8-hydroxypalmitoyl]taurine, the oviposition-deterring pheromone of the European cherry fruit fly Rhagoletis cerasi L., was achieved by starting from 2,3,4,6-tetra-O-pivaloyl-α-D-glucopyranosyl bromide (2), taurine (4), ethyl (R)-3-hydroxybutanoate (5), propargyl alcohol (6), methyl acetoacetate (7), and 1,6-hexanediol (8).

Enzymatic and protein patterns at different developmental stages in the cherry fruit fly Rhagoletis cerasi L.

Protein patterns and two isoenzyme systems (leucine aminopeptidase, LAP, and alanine aminopeptidase, AAP) were examined in the cherry fruit fly Rhagoletis cerasi L. at different stages of ontogeny LAP activity was quantitatively determined. Differences were observed in protein patterns for puparia in diapause, post-diapause and at adult emergence. Some LAP and AAP isoenzymes appear in post-diapause which had not been observed during diapause. It is suggested that there is a direct link between variations in protein patterns and proteolytic activity.

Optical and chemosensory stimuli involved in host recognition and oviposition of the cherry fruit fly Rhagoletis cerasi L.

AbstractThe aim of this study was to find out to which extent the narrow host spectrum of Rhagoletis cerasi Linné (Trypetidae, Diptera) is due to sensory barriéres or unsuitable texture and composition of nonhost fruits. Preference or partial avoidance of fruit dummies made of thin‐walled wax hemispheres (fig. 6) and impregnated with either host‐ or nonhost‐volatiles by gravid R. cerasi was demonstrated.The volatiles of a fruit species were obtained by passing purified air (3 1/min) for 48 hours over ˜ 1 kg of unripe berries (table) to an adsorbent (fig. 8), from which the odour was recovered by solvent extraction. The host fruit odours derived from the fly honeysuckle (Lonicera xylosteum, Caprifoliaceae) or the sweet cherry (Prunus avium, Rosaceae) increased the rate of oviposition by 27 or 36%, whilst the nonhost odours obtained from fruits of the mealy tree (Viburnum lantana, Caprifoliaceae), the cornel tree (Cornus mas, Cornaceae) or the common dogwood (Cornus sanguinea, Cornaceae) subdued it by 37, 33 or 52%, respectively. The oviposition rate of R. cerasi can thus be enhanced by host fruit odours or suppressed by odours of nonhost fruits.Female cherry fruit flies were found to lay 1.7‐2.2 times more eggs in fruit dummies displaying a luminosity contrast with the background (black dummies on white surface) than in dummies which had the same coloration as the background (either black or white). Thus, the luminosity contrast encouraged oviposition more than the odour of host fruits (fig. 7). Host finding of R. cerasi seems to depend on phototelotactic orientation and host recognition on kinaesthetic as well as tactile behaviour responses, while the extent of egg laying appears to be regulated by host and nonhost odours.ZusammenfassungOptische und chemosensorische Reize zur Wirtserkennung und Eiablage der Kirschfruchtfliege Rhagoletis cerasi L.Es sollte geklärt werden, ob das beschränkte Wirtsspektrum der Kirschfruchtfliege Rhagoletis cerasi Linné (Trypetidae, Diptera) auf sensorischen Barrieren oder auf ernährungsphysiologisch ungeeigneter Zusammensetzung bzw. Beschaffenheit der Früchte von Nichtwinen beruht. Die Bevorzugung bzw. partielle Vermeidung dünnwandiger Wachshalbkugeln (als Fruchtattrappen, Abb. 6), imprägniert mit den Düften der Wirts‐ bzw. Nichtwirts‐Früchte, von trächtigen Weibchen der Kirschfruchtfliege wurde gezeigt.Die zu untersuchenden Fruchtdüfte wurden gewonnen, indem jeweils ˜ 1 kg der noch unreifen Beeren (Tab.) während 48 Stunden mit Luft überströmt (3 1/min) und die flüchtigen Stoffe in einem Adsorptionsmittel (Abb. 8) aufgefangen und später daraus extrahiert wurden. Die Fruchtdüfte der Roten Heckenkirsche (Lonicera xylosteum, Caprifoliaceae) oder der Vogelkirsche (Prunus avium, Rosaceae) erhöhten die Eiablage an Fruchtattrappen um 27 bzw. 36%, wogegen sie von den Fruchtdüften des Wolligen Schneeballs (Viburnum lantana, Caprifoliaceae), der Kornelkirsche (Cornus mas, Cornaceae) oder des Roten Hartriegels (Cornus sanguinea, Cornaceae) um 37, 33 bzw. 52% herabgesetzt wurde.Es wurde nachgewiesen, daß trächtige Weibchen von R. cerasi 1.7‐2.2mal mehr Eier in schwarze Fruchtattrappen mit weißem Hintergrund als in Fruchtattrappen, die die gleiche Farbe wie der Hintergrund (schwarz bzw. weiß) hatten, legen (Abb. 7). Demnach begünstigt der Helligkeitskontrast zwischen Wirtsfrucht und Hintergrund die Eiablage mehr als der Wirtsduft. Bei R. cerasi dürfte die Wirtsauffindung auf phototelotaktischer Orientierung, die Wirtserkennung auf kinaesthetischen und taktilen Verhaltensreaktionen und die Regulierung der Eiablage vorwiegend auf vorhandenen Wirtsdüften bzw. fehlenden Nichtwirtsdüften beruhen.

Versuche zur Anköderung und zum Fang der Kirschenfliege (Rhagoletis cerasi L.)

1. The application of bait traps to catch the cherry fruit fly (Rhagoletis cerasi L.) is desirable for the practice of the plant protection service as well as for the elucidation of scientific questions. Therefore the possible usefulness of some substances as cherry fruit fly bait has been tested.