The vinegar fly Drosophila suzukii (Matsumura) (Diptera Drosophilidae), spotted wing drosophila, is a highly polyphagous invasive pest endemic to South East Asia, which has recently invaded western ...countries. Its serrated ovipositor allows this fly to lay eggs on and damage unwounded ripening fruits, thus heavily threatening fruit production. D. suzukii is spreading rapidly and economic losses are severe, thus it is rapidly becoming a pest of great concern. This paper reviews the existing knowledge on the pest life history and updates its current distribution across Europe. D. suzukii presence has now been reported in nine European countries. Nonetheless, several knowledge gaps about this pest still exist and no efficient monitoring tools have been developed yet. This review is aimed at highlighting the possible research approach which may hopefully provide management solutions to the expanding challenge that D. suzukii poses to European fruit production.
Determining upper thermal limits of tephritid fly pupae can have practical implications for disinfesting soils and for predicting differential impacts of global warming on flies and their parasites. ...Here, upper thermal limits of Rhagoletis indifferens Curran (Diptera:Tephritidae) pupae and pteromalid wasps (Hymenoptera: Pteromalidae) inside puparia were determined. Puparia receiving sufficient chill to terminate pupal diapause were exposed to temperatures ramped linearly over 6 h from 21 °C to 47.8, 49.4, 51.1, 55.0, or 60.0 °C for a 0-h hold time. Flies eclosed when pupae were exposed to 47.8 °C but not to 49.4, 51.1, 55.0, or 60.0 °C nor in a separate test to 47.8 °C for 1–3 h hold times. All fly pupae in treatments where no eclosion occurred were dead based on puparial dissections. In contrast, adult wasps eclosed when puparia were exposed to 49.4 and 51.1 °C for 0 h and to 47.8 °C for 1- and 2-h hold times. Despite the greater upper thermal limits of wasps, heat delayed eclosion times of both adult flies and wasps, in 47.8 and 51.1 °C treatments, respectively. In separate tests, longevity of flies exposed as pupae to 47.3–48.6 °C was greater than of control flies, while longevity of control wasps and wasps exposed as immatures to 47.8–51.1 °C did not differ. Flies exposed as pupae to 47.2–48.6 °C produced as many eggs and puparia as control flies. Results suggest heat could be used to disinfest soils of puparia while sparing parasitoids. In addition, extreme heat waves due to global warming might be more detrimental to fly pupae than immature wasps.
Target and non-target Rhagoletis Loew, 1862 (Diptera: Tephritidae) flies trapped in surveys can provide new information on fly abundances, ecologies, and distributions. Here, data from surveys for ...native R. indifferens Curran, 1932 in non-commercial sweet cherry trees and non-native R. pomonella (Walsh, 1867) in non-commercial apple, crabapple, and hawthorn trees in central Washington State, U.S.A. were used to determine relative abundances of target and non-target Rhagoletis on traps and to test the hypotheses that fly abundances are site, tree type, and seasonal period dependent. Rhagoletis indifferens was the most abundant Rhagoletis in cherry trees. Non-native R. completa Cresson, 1929 was the most abundant Rhagoletis caught in R. pomonella host trees, with overall results suggesting it is the most numerous and/or dispersive Rhagoletis in central Washington. With support from the literature, we infer that: R. pomonella is less tolerant of arid central Washington summers than R. completa, native R. zephyria Snow, 1894, R. indifferens, and native R. basiola (Osten Sacken, 1877); Rhagoletis species diversity is lower in suburban than rural habitats due to the predominant host plants present; all fly species disperse annually at similar relative abundances, resulting in geographic range expansions over a few generations; and peak seasonal dispersal of flies to non-natal tree species coincides with natal host fruit development, resulting in colonization of new fruiting host patches. Differential fly tolerances of arid summer climates due to adaptation or preadaptation, habitat type, and annual and seasonal dispersal patterns could explain abundances and distributions of native and non-native Rhagoletis species in central Washington.
Fruit developmental stage affects oviposition responses by tephritid fruit flies, but the role temperature plays in these responses to different fruit stages remains largely unknown. Here, ...temperature effects on oviposition rates of western cherry fruit fly, Rhagoletis indifferens Curran, in different stages of Bing sweet cherry (Prunus avium L.) were determined in no-choice experiments. Stage 1 (green), stage 2 (green-yellow to orange red), stage 3 (yellow-orange to red), and stage 4 cherries (red to burgundy) were exposed to flies at 15.6, 21.1, 26.7, and 32.2°C for 3 h and oviposition recorded. Oviposition was lower at 15.6°C than at all other test temperatures within all four cherry stages. Regression analysis using the three higher temperatures indicated there were significant cherry stage and temperature effects and a significant cherry stage × temperature interaction. The oviposition–temperature relationship was best explained by linear or curvilinear equations, depending on cherry stage. Oviposition in stage 1 cherries was lowest of the four stages and was not or linearly related to temperature. Oviposition in stage 2 cherries was greater and was related to temperature in a linear or curvilinear response. Oviposition was greatest in stage 3 and 4 cherries, with curvilinear and linear equations, respectively, best explaining oviposition–temperature relationships. Results suggest that temperatures and cherry stage together rather than cherry stage alone may have selected for behaviors leading to oviposition responses in R. indifferens.
Western cherry fruit fly, Rhagoletis indifferens Curran, is a quarantine pest of sweet cherries in the Pacific Northwest of the United States that overwinters as diapausing pupae. Eclosion responses ...of R. indifferens puparia to different low temperature durations and postdiapause conditions affect the pest status of the fly. Here, we determined the effects of holding R. indifferens puparia at 3°C for 0, 1, 2, 5, 10, 15, and 20 wk on adult eclosion times and rates at two simulated temperate and two simulated tropical climate treatments over 40 wk. When puparia were chilled 0, 1, or 2 wk, adult eclosion across the four climate treatments displayed a bimodal distribution with low eclosion at 3 wk and high eclosion at 23–35 wk. When puparia were chilled ≤ 10 wk, there was a weaker bimodal distribution. However, when puparia were chilled 15–30 wk, eclosion was more synchronous and occurred at 5–7 wk across the four postchill climate treatments. Eclosion was greater at a postdiapause temperature of 26°C than 23°C. Timing to 50% eclosion was faster at longer photoperiod (16:8 L:D) than shorter (12:12 L:D). The bimodality of eclosion in respect to the duration of low temperature exposure may be indicative of univoltine insect species with obligate diapause that may span over two seasons.
Insecticides mixed in sugar-protein baits or insecticides alone have been used to control tephritid fruit flies for many years. Here, effects of cyantraniliprole, spinetoram, and the biopesticide ...Chromobacterium subtsugae extract in sucrose-yeast extract bait or alone on kill and oviposition of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera:Tephritidae), were evaluated in the laboratory. Flies were exposed to dry insecticide bait or insecticide alone in the presence or absence of a nontoxic food strip. Spinetoram alone caused greater mortality than cyantraniliprole alone, while cyantraniliprole in bait caused mortality as high as spinetoram bait and greater mortality than cyantraniliprole alone. Chromobacterium subtsugae extract alone but not in bait caused significant mortality compared with controls, but was much less effective than cyantraniliprole and spinetoram. Spinetoram alone reduced oviposition more than cyantraniliprole alone. However, cyantraniliprole bait reduced oviposition as much or more than spinetoram alone or spinetoram bait. Cyantraniliprole and spinetoram baits caused greater mortality when a nontoxic food strip was absent than present, but there was no corresponding reduction in oviposition. Chromobacterium subtsugae extract did not significantly reduce oviposition compared with controls. Potential benefits of using cyantraniliprole baits as an additional or alternative method to using more toxic spinosyn insecticides for controlling R. indifferens warrant study.
Western cherry fruit fly, Rhagoletis indifferens (Curran; Diptera:Tephritidae), occurs in unmanaged cherries (Prunus spp.) across dry climates in Washington State and other regions in western United ...States and Canada. To help explain the fly's distribution in arid climates, we determined the effects of adding water to bare and grass-covered soils on pupal survival rates and adult emergence patterns of R. indifferens in central Washington. Water was added (‘irrigated’) or not to bare soil and grass-covered soil in cylinders pressed into the ground. Larvae were added to cylinders and pupal survival and adult fly emergence determined over three seasons. Irrigating bare soil had no effect on pupal survival or adult emergence, but in grass-covered soil, irrigation increased pupal survival (15.2–17.0% vs 6.7–9.5%) and adult emergence (2 of 3 yr, 12.8 and 24.1 vs 1.1 and 11.6%; no difference in 1 yr). Pupal survival was greater in bare (24.5–47.7%) than grass-covered soil (6.7–17.0%). Moisture was higher in irrigated than unirrigated treatments but within irrigated treatments, moisture in bare versus grass-covered soil did not differ. In both irrigated and unirrigated treatments, humidity in soil 5 cm below the surface where many pupae reside was >60%, including during summers. Results suggest R. indifferens pupae tolerate unirrigated soils during summer because soil moisture and high humidity there can prevent desiccation, contributing to the fly's wide distribution and abundance in dry climates, and that dry, grass-covered soils or mulch barriers in mid- and late-summer could reduce fly survival under some conditions.
The paper presents the data collected from an ecological plot of sweet cherries with an area of 0.5 ha, where different methods of monitoring and combating the main pests were tested: European cherry ...fruit fly - Rhagoletis cerasi L. and black cherry aphid - Myzus cerasi F. The study took place during the years 2019-2020. European cherry fruit fly monitoring - Rhagoletis cerasi L. was performed with both atraCERAS optical panels and Decis Trap devices, with both a warning and control role, the results obtained highlighting a similar flight dynamics. The control of the European cherry fruit fly, carried out by direct control with the help of Decis Trap devices, the dose of 100 traps / ha, proved to be effective, the Abbott effectiveness indicator registering values between 83.4 - 90.5% in 2019, respectively 81.6 - 87.8% in 2020, depending on the studied variety. To control the black cherry aphid - Myzus cerasi F., the product Prev-Am was mainly used, based on orange oil, which was used with good results for the first attacks observed.
During the last decades, the economic importance of tephritid fruit flies (FF) has increased worldwide because of recurrent invasions and expansions into new areas, and reduced control capabilities ...of current control systems. Efficient monitoring systems, thus, are required to provide fast information to act promptly. With this aim in mind, we developed two electronic trap (e‐trap) versions for adult FF: one with specific volatiles for male and female adult Ceratitis capitata, and the second, based on the attraction of adult FF to yellow colour, targeting Dacus ciliatus, Rhagoletis cerasi and Bactrocera oleae. In the case of B. oleae, the female pheromone and ammonium bicarbonate were added as synergists. In the two versions, attracted FF were retained in the trap on glued surfaces. Real‐time images of the surfaces were automatically taken and transmitted to a server. We tested the two e‐trap versions in insect‐proof cages, where flies were released and recaptured, and in commercial orchards throughout the Mediterranean: C. capitata in peach orchards in Italy; R. cerasi in cherry orchards in Greece; B. oleae in olive orchards in Spain and in Greece; and D. ciliatus in melons in plastic tunnels in Israel. The e‐trap showed excellent abilities to transmit real‐time images of trapped FF and a high specificity for trapping different FF species. The ability of the entomologist to correctly classify FF from images in the office was >88%. In addition, average number of flies/trap in e‐trap grids did not differ from numbers reported on grids of conventional traps that were operating simultaneously. The e‐traps developed and tested in this study provide the basis for the real‐time monitoring of FF were no olfactory attractants are available, and for the surveillance of alien FF incursions where generic, but not specific, olfactory attractants exists.
Insect pests pose a great threat to global food security. Improved methods for assessment of the risk of pest establishment are needed to enhance informed decision-making, to develop cost-effective ...pest management strategies, and to design quarantine policies for preventing the spread of pests. We evaluated the capabilities of a correlative and a process-based mechanistic niche model, and their combination, to assess the risk of pest establishment. The correlative model MaxEnt and the process-based mechanistic model CLIMEX were used to assess the risk of establishment of western cherry fruit fly,
Rhagoletis indifferens
Curran (Diptera: Tephritidae) in California. We integrated
R. indifferens
occurrence records and spatial environmental variables using MaxEnt to assess the potential risk of establishment of this pest. The CLIMEX model was developed using eco-physiological tolerances of
R. indifferens
. The predictive performance of the MaxEnt model improved by including the host species' distribution and Ecoclimatic Index generated using the CLIMEX model. The best model predicted no risk for
R. indifferens
establishment in the Central Valley around the areas where sweet cherries are produced in California. Most of the high to very high risk areas for
R. indifferens
were predicted in northern parts of California and the Sierra Nevada Mountains, where the fly exists on its native host, bitter cherry
Prunus emarginata
(Douglas) Eaton. Precipitation of driest quarter, degree days with average temperatures ≥8.3°C, degree days with average temperatures ≤5°C, and mean diurnal range in temperature were the strongest predictors of
R. indifferens
distribution in western North America. We showed that the predictive power of correlative niche models can be improved by including outputs from the process-based mechanistic niche models. Overall results suggest that
R. indifferens
is unlikely to establish in the commercial cherry-growing areas in the Central Valley of California, largely because heat stress is too high and chilling requirement in those areas is not met.
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