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Standing less than 10cm in height, being the width of a quarter, and occupying a small stretch of limestone barrens on the island of Newfoundland, Canada means the endangered Braya [...]

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive pest of many small and soft fruits. We present the first results concerning its oviposition in the canopy of a sweet cherry (Prunus avium Linnaeus; Rosaceae) orchard. We examined the distribution of arthropods emerging from fruits of five cultivars ripening successively over seven weeks, in interior and border rows, within four regions of the tree canopy (top/bottom height × north/south aspect), and measured the associated fruit ripeness (ºBrix). Single fruits were reared for more than two weeks: 1328 arthropods emerged from 887 cherries in June, and 10 426 emerged from 1071 cherries in July. When populations were low, significantly more D. suzukii were present in the northernmost row and northern canopy aspect. Later, its distribution with respect to cherry row, height, and aspect was homogenous. Drosophila suzukii density per sweet cherry was highest in the latest ripening cultivar, when its distribution was not homogeneous; significantly more D. suzukii were in the centre than the southernmost row, in the lower canopy, and the southern aspect, than elsewhere. In the early season, single egg clutches were found without aggregation. As population density increased, so did intraspecific aggregation, but D. suzukii did not co-exist with other Drosophila Fallén species, nor with Rhagoletis indifferens Curran (Diptera: Tephritidae) when present. [ABSTRACT FROM AUTHOR]

Spotted-wing drosophila, Drosophila suzukii, (Matsumura) (Diptera: Drosophilidae), has become a serious pest of soft fruit in the Okanagan Valley of British Columbia, Canada since its detection in 2009. The study was conducted to determine the distribution of D. suzukii and damage levels in grapes. Apple cider vinegar-baited traps placed in table and wine grape (Vitis vinifera Linnaeus; Vitaceae) vineyards during 2011–2013 demonstrated that D. suzukii was numerous in all sites, with earliest emergence and highest numbers recorded in 2013. Drosophila suzukii were reared from intact and damaged table grapes and damaged wine grapes collected from the field, but not from intact wine grapes. Drosophila suzukii were reared in low numbers in 2011 from intact fruit of 11 wine grape cultivars exposed artificially in the laboratory. Susceptibility of intact wine grapes under laboratory conditions in 2011 when sour rot was widespread might relate in part to undetected infections of berries due to weather conditions. Identification of Drosophila Fallén species revealed that D. suzukii comprised a small portion of the total. Our results demonstrate that healthy wine grapes in the Okanagan Valley of British Columbia are largely undamaged by D. suzukii, while certain table grape cultivars should be protected from attack. [ABSTRACT FROM AUTHOR]

The sterile insect technique is a new approach for the integrated management of Drosophila suzukii Matsumura (Diptera: Drosophilidae), an invasive pest in North America. We evaluated, under laboratory conditions, the mating capacities and success of male D. suzukii, irradiated at a dose of 120 Gy, with and without competition. We also explored the tendency of females to remate depending if their first mate was irradiated or not. We observed that irradiated males have the same mating capacity as control males, copulating with, respectively, 6.4 ± 1.9 females versus 6.9 ± 2.0 females in a 24-hour period. Irradiated males won the competition 37.5% of times, which is not significantly different from competiveness of control males. Female remating can be considered infrequent and not significantly influenced by male treatment: 7.4% of the females first mated with control males and 18.8% of the females first mated with irradiated males remated when given the opportunity two days and four days after the first mating. Latency before mating and mating duration were not significantly influenced by male treatment, but by presence of male competition. Overall, irradiated males thus seem to be as performant as control males, which is an important condition for a successful sterile insect technique programme. [ABSTRACT FROM AUTHOR]

The insect commensal microbiota consists of prokaryotes and eukaryotes. We explored the effect of diet and the persistence of the gut microbiota across generations in Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). We transferred subsets of a single population of D. suzukii to different fruit-based diets (blueberry (Vaccinium Linnaeus; Ericaceae), raspberry (Rubus Linnaeus; Rosaceae), and strawberry (Fragaria × ananassa Duchesne; Rosaceae)) for three generations and then returned them to a common, banana-based, diet. We used 16S rDNA (Bacteria) and ITS (internal transcribed spacer; Fungi) sequencing of female endosymbiont-free flies to identify the microbiota. We identified 2700 bacterial and 350 fungal operational taxonomic units (OTUs); there was no correlation between the number of bacterial and fungal OTUs in a sample. Bacterial communities were dominated by Proteobacteria (especially Acetobacteraceae); Ascomycota dominated the fungal communities. Species diversity of both bacteria and fungi differed among diets, but there were no differences in species-level diversity when these D. suzukii were returned to a control diet. A principle coordinates analysis revealed no differences in the bacterial or fungal community in the first generation on fruit diets, but that the communities diverged over the next two generations; neither fungal and bacterial communities converged after one generation on control food. We conclude that diet changes the D. suzukii microbiota, and that these changes persist for more than one generation. [ABSTRACT FROM AUTHOR]

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a cosmopolitan polyphagous pest on unripe soft-skinned fruits. We sought to determine (1) temperature treatments that could be used to kill immature D. suzukii in fruit or packaging and (2) whether development on different fruits led to differences in cold tolerance of immature D. suzukii. We reared animals from egg on a banana-based laboratory diet and diets made of apple (Malus domestica Borkhausen; Rosaceae), blueberry (Vaccinium Linnaeus; Ericaceae), cherry (Prunus avium Linnaeus; Rosaceae), grape (Vitis Linnaeus; Vitaceae), orange (Citrus × sinensis (Linnaeus) Osbeck; Rutaceae), raspberry (Rubus Linnaeus; Rosaceae), or strawberry (Fragaria × ananassa Duchesne; Rosaceae) homogenate in agar and measured development time, adult body size, and cold tolerance. Diet type had complex effects on development time; in particular, D. suzukii reared on apple-based or blueberry-based diets developed more slowly to a smaller adult body size than those on other diets. Cold exposure killed eggs and both first and second instars. Survival of 24 hours at +4 °C by feeding third instars was lowest in blueberry and cherry. Five days at +0.6 °C killed all feeding third instars; this treatment is likely sufficient for targeting D. suzukii in fruit. Two hours at −5 °C or −6 °C killed all wandering third instars and pupae; this exposure could be sufficient for sanitation of packaging. [ABSTRACT FROM AUTHOR]

Spotted-wing drosophila (Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)) is a pest of tender fruit and berry crops because female flies oviposit in ripening fruit. Frequent insecticide applications are needed for control during fruit ripening, with few noninsecticide options available. The effect of interplanting peppermint (Mentha × piperita Linnaeus (Lamiaceae)) in strawberry (Fragaria × ananassa Duchesne (Rosaceae)) on D. suzukii fruit infestation was investigated because peppermint essential oil deterred D. suzukii from fruit in the laboratory, and interplanted aromatic plants reduced crop pest populations in other field studies. Regardless of whether peppermint was untrimmed or periodically trimmed to reduce shading of strawberries and promote release of volatiles, D. suzukii infestation was consistently lowest in strawberries adjacent to no peppermint. Interplanted peppermint also reduced strawberry yield in the second year of the experiment. Abundance of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), a strawberry pest, was higher in plots with peppermint, but abundances of Ligyrocoris diffusus (Uhler) (Hemiptera: Rhyparochromidae) and Neortholomus scolopax (Say) (Hemiptera: Lygaeidae), seed feeders but not common strawberry pests, were lower in plots with peppermint. Overall, interplanted peppermint is not recommended for D. suzukii management, but other strategies for using volatile, repellent compounds in the field should be investigated. [ABSTRACT FROM AUTHOR]

The characteristics of the juvenile developmental environment of an individual can have many important consequences for their adult reproductive success as it may shape the development and expression of phenotypes that are relevant to the later operation of sexual selection. Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an economically important invasive pest species that lays its eggs in many types of soft fruits and potentially experiences large intrapopulation spatial and temporal variation in its nutritional developmental environments. Here, we examine whether the larval nutritional developmental environment influences D. suzukii mate choice, egg production, and offspring performance. Using D. suzukii raised on diets differing in their nutritional quality, we examined mating preferences, fecundity, and offspring survivorship in "no-choice," "female choice," and "male choice" reproductive contexts. We found evidence for both adaptive and nonadaptive mate choice behaviours associated with the phenotypes of D. suzukii that had developed in different nutritional environments. These results reveal the complex nature of the relationship between the developmental environment and individual reproductive success in D. suzukii, which has important potential implications for future management plans involving this species. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), the spotted-wing drosophila, is an invasive pest of fruit crops, which appeared in eastern Canada in 2010. It represents a major threat to lowbush blueberry (Vaccinium angustifolium Aiton; Ericaceae) in the Saguenay-Lac-Saint-Jean region, Québec, Canada, at the northern limits of its distribution. The dynamics, overwintering capacity, population fluctuations, and damage to lowbush blueberry of D. suzukii are unknown in Saguenay-Lac-Saint-Jean. We aimed to 1) document D. suzukii abundance and phenology in lowbush blueberry in separate localities; 2) evaluate the potential of D. suzukii to overwinter and examine population dynamics over three seasons; and 3) study the spatial distribution of D. suzukii in lowbush blueberry fields with respect to forested borders. Drosophila suzukii is abundant in lowbush blueberry fields of Saguenay-Lac-Saint-Jean. In spring, D. suzukii were absent until late June, when few summer-morph females appeared. Drosophila suzukii densities started to increase regularly in August, with increasing male proportions, to culminate in fall at high levels with balanced sex ratios. Overwintering remains uncertain, D. suzukii being undetectable in spring despite intensive trapping. Appearance of diapausing winter morphs at high densities indicates that D. suzukii responds appropriately to local conditions preceding cold winter. Models of variation of D. suzukii densities and lowbush blueberry fruit infestation with distance from borders indicate that forest borders are favoured habitats over lowbush blueberry fields and the source of D. suzukii moving to some extent into lowbush blueberry fields. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a pest that causes severe damage to various fruits, generating economic losses. We evaluated its potential geographic distribution under current and future climatic conditions using an ecological niche modelling approach, based on the largest available database on occurrence records for this species. Additionally, we identified areas of risk to agricultural land and crops. Predictions under current climatic conditions indicated that this species is likely to be present across broad swaths of the United States of America, southeastern Asia, southeastern Australia, New Zealand, and Europe. We predict considerable expansion of its potential range for 2050, mainly in the Northern Hemisphere, because of ongoing climate change, under both low and high emissions scenarios. [ABSTRACT FROM AUTHOR]

Native to southeast Asia, the spotted-wing drosophila (Drosophila suzukii (Matsumura); Diptera: Drosophilidae) has become a major pest of small fruits in the Americas and Europe. Field studies were conducted over a two-year period (2015–2016) in cultivated highbush blueberry (Vaccinium corymbosum Linnaeus; Ericaceae) fields and adjacent non-crop habitats containing wild blueberries in New Jersey (United States of America). We tracked seasonal changes in D. suzukii adult abundance and fruit infestation throughout the ripening period (June–August). In both years, D. suzukii adult counts post-harvest were generally higher in traps located in non-crop habitats compared with those located in highbush blueberry fields. Wild and cultivated fruits synchronised in maturation, and the numbers of eggs laid and of emerged adults in both fruit types were comparable for most of the season, although sometimes these numbers were higher in wild fruits post-harvest. Overall, immature success (measured as the per cent egg-to-adult survival) was also mostly higher in wild than in cultivated fruits. Altogether, these studies document that non-crop habitats, and wild hosts therein, are used by D. suzukii during fruit ripening and may serve as potential sources of infestation to nearby highbush blueberry fields. Hence, methods that reduce D. suzukii populations in non-crop habitats may help manage this pest in neighbouring highbush blueberries. [ABSTRACT FROM AUTHOR]

The presence ofRhagoletisfruit flies in Newfoundland, Canada, was investigated by rearing large numbers of the fruits of known and potential host plant species. ThreeRhagoletisspecies,R. tabellaria(Fitch),R. basiola(Osten Sacken), and the cherry pest speciesR. fausta(Osten Sacken), were found to occur naturally in Newfoundland, representing a range extension of some 500 km forR. tabellariaandR. basiola. Rhagoletis faustahad previously been reported from sticky traps used to monitorR. mendaxCurran, which is not known from the province. To investigate the route by which the two new species may have colonized Newfoundland,R. tabellariaadults were sequenced for a mitochondrial genome fragment (COI–tRNA-Leu–COII–tRNA-Lys). This sample was genetically identical or similar to samples from other widely distributed sites in North America, suggesting that the presence ofR. tabellariain Newfoundland is the result of postglacial dispersal rather than survival in a glacial refugium. The implications of these findings forRhagoletismanagement in Canada are discussed. [ABSTRACT FROM AUTHOR]

The cabbage maggot, Delia radicum (L.), is a serious pest of cruciferous crops in temperate regions of North America and Europe. The effects of undersowing rutabaga, Brassica napus L. subsp, rapifera Metzg. (Brassicaceae), with white clover, Trifolium repens L. (Leguminosae), on second-generation cabbage maggot and its natural enemies were studied in Newfoundland in 1997 and 1998. In 1997, totals of 1311 and 724 eggs were recovered from bare and undersown plots, respectively. More eggs were present in bare plots than undersown plots on various specific dates. In 1997, rutabagas from bare plots weighed more than those from undersown plots, although damage ratings were similar, suggesting that competition, not cabbage maggot feeding, caused the yield differences. In 1998, there were few cabbage maggots present and little damage or yield reduction in either treatment. Similar numbers of cabbage maggot pupae were extracted and reared from each treatment in each year. In 1997, of the pupae reared from undersown plots, 48% produced cabbage maggot flies, 14% produced parasitic Hymenoptera, and 8% produced Aleochara bilineata Gyllenbal (Coleoptera: Staphylinidae); 19% of the pupae from bare plots produced cabbage maggot flies, 8% produced parasitic Hymenoptera, and 36% produced A. bilineata. More A. bilineata were captured in pitfall traps in bare plots than in undersown plots. The effect of clover on carabid beetles was species specific. There were more Bembidion lampros (Herbst) and Amara bifrons (Gyllenhal) in bare plots in 1997, and more Pterostichus melanarius (Illiger) in undersown plots in both years. Despite consistently lower egg numbers in undersown plots than in bare plots, the numbers of pupae in the two treatments were similar at the end of the season. We speculate that this may be due to differential, density-dependent mortality of immature stages of cabbage maggot caused by predators and parasitoids. [ABSTRACT FROM AUTHOR]

Cranberry (Vaccinium macrocarpon) has been commercially developed since the late 1990's in Newfoundland and Labrador. At that time, the insect fauna of the extensive stands of native, wild cranberry was not known, although these might provide a reservoir for pests to move to commercial sites. The occurrence and distribution of cranberry-feeding insects were assessed in wild stands to help cranberry growers prepare for the insect pests they might have to manage. Adults of the cranberry fruitworm, Acrobasis vacciniiwere recovered in pheromone traps and larvae found in berries. The fruitworm was common and widespread. Moths of the cranberry girdler, Chrysoteuchia topiaria were caught in pheromone traps, but larvae were not recovered from plant or soil samples. There was no evidence of the black-headed fireworm, Rhopobota naevana, the cranberry weevil, Anthonomus musculus, the red-headed flea beetle, Systena frontalis, or the cranberry tipworm, Dasineura oxycoccana, serious cranberry pests in other areas. However, larvae of the lingonberry fruitworm, Grapholita libertina, were found infesting cranberry at one site in 1998. Of the species found in this study, A. vaccinii probably represents the most serious threat to the industry. [ABSTRACT FROM AUTHOR]