Racemic Pheromone Blends Disrupt Mate Location in the Invasive Swede Midge, Contarinia nasturtii.

Swede midge, Contarinia nasturtii Kieffer, is an invasive cecidomyiid pest that causes serious losses of Brassica oilseed and vegetable crops in the Northeastern U.S. and Canada. Currently, few alternatives to systemic insecticides exist for its management. Because a single feeding larva can render heading Brassica crops unmarketable, management strategies that prevent oviposition are needed urgently. Pheromone-mediated mating disruption is a promising management approach for swede midge because it prevents mating and subsequent crop damage. While the swede midge pheromone has been identified, one of the major barriers to using it in mating disruption is the high cost of synthesis. Racemic blends, consisting of natural and non-natural stereoisomers, could be useful for mating disruption because they are cheaper to produce. However, it is not clear whether racemic pheromone blends attract males and/or prevent them from locating and mating with females. Here, we studied the behavior of male swede midge in Y-tube and wind tunnel bioassays to pheromone blends. Specifically, we tested whether males: (1) are attracted to different doses of pheromone, (2) discriminate between blends comprising natural stereospecific or racemic components, or a combination thereof, and (3) are able to locate and copulate with females in pheromone-permeated olfactometers. We found that picogram amounts of pheromone attracted males and prevented them from locating females in y-tube olfactometers. While males were more attracted to stereospecific blends, compared to racemic blends, all blends tested prevented nearly all males mating with females. Therefore, low dose racemic blends may be promising for pheromone-mediated mating disruption.

The Invasive Liriomyza huidobrensis (Diptera: Agromyzidae): Understanding Its Pest Status and Management Globally.

Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.

Effect of Temperature and Host Life Stage on Efficacy of Soil Entomopathogens Against the Swede Midge (Diptera: Cecidomyiidae).

The Swede midge, Contarinia nasturtii Kieffer, is an economically significant pest of cruciferous crops in Canada and the northeastern United States. The effect of temperature on the virulence of three entomopathogenic nematode species, Heterorhabditis bacteriophora, Steinernema carpocapsae, and Steinernema feltiae, the entomopathogenic fungus Metarhizium brunneum, and a H. bacteriophora+M. brunneum combination treatment to C. nasturtii larvae, pupae, and cocoons was investigated. In the laboratory, all three nematode species successfully reproduced inside C. nasturtii larvae: H. bacteriophora produced the highest number of infective juveniles per larva, followed by S. carpocapsae and S. feltiae. H. bacteriophora and the H. bacteriophora+M. brunneum combination treatment generally caused the highest mortality levels to all C. nasturtii life stages at 20°C and 25°C, whereas S. feltiae caused the highest mortality to larvae and pupae at 16°C. No nematode species caused significant mortality when applied in foliar treatments to the infested host plant meristem and, in spite of high mortality, an antagonistic interaction was observed in the H. bacteriophora+M. brunneum combination treatment when compared with expected mortality. In trials conducted in broccoli fields in Elora, Ontario, M. brunneum suppressed adult emergence of C. nasturtii from infested soil in 2012 and all nematode treatments successfully suppressed adult emergence in 2013; however, no significant effects were observed in field trials conducted in Baden, Ontario.

Climate and host plant availability impact the future distribution of the bean leaf beetle (Cerotoma trifurcata).

The bean leaf beetle, Cerotoma trifurcata, has become a major pest of soybean throughout its North American range. With a changing climate, there is the potential for this pest to further expand its distribution and become an increasingly severe pest in certain regions. To examine this possibility, we developed bioclimatic envelope models for both the bean leaf beetle, and its most important agronomic host plant, soybean (Glycine max). These two models were combined to examine the potential future pest status of the beetle using climate change projections from multiple general circulation models (GCMs) and climate change scenarios. Despite the broad tolerances of soybean, incorporation of host plant availability substantially decreased the suitable and favourable areas for the bean leaf beetle as compared to an evaluation based solely on the climate envelope of the beetle, demonstrating the importance of incorporating biotic interactions in these predictions. The use of multiple GCM-scenario combinations also revealed differences in predictions depending on the choice of GCM, with scenario choice having less of an impact. While the Norwegian model predicted little northward expansion of the beetle from its current northern range limit of southern Ontario and overall decreases in suitable and favourable areas over time, the Canadian and Russian models predict that much of Ontario and Quebec will become suitable for the beetle in the future, as well as Manitoba under the Russian model. The Russian model also predicts expansion of the suitable and favourable areas for the beetle over time. Two predictions that do not depend on our choice of GCM include a decrease in suitability of the Mississippi Delta region and continued favourability of the southeastern United States.

Optimizing Trap Design and Trapping Protocols for Drosophila suzukii (Diptera: Drosophilidae).

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a recent invasive pest of fruit crops in North America and Europe. Carpophagous larvae render fruit unmarketable and may promote secondary rot-causing organisms. To monitor spread and develop programs to time application of controls, further work is needed to optimize trap design and trapping protocols for adult D. suzukii. We compared commercial traps and developed a new, easy-to-use plastic jar trap that performed well compared with other designs. For some trap types, increasing the entry area led to increased D. suzukii captures and improved selectivity for D. suzukii when populations were low. However, progressive entry area enlargement had diminishing returns, particularly for commercial traps. Unlike previous studies, we found putting holes in trap lids under a close-fitting cover improved captures compared with holes on sides of traps. Also, red and black traps outperformed yellow and clear traps when traps of all colors were positioned 10-15 cm apart above crop foliage. In smaller traps, attractant surface area and entry area, but not other trap features (e.g., headspace volume), appeared to affect D. suzukii captures. In the new, plastic jar trap, tripling attractant volume (360 vs 120 ml) and weekly attractant replacement resulted in the highest D. suzukii captures, but in the larger commercial trap these measures only increased by-catch of large-bodied Diptera. Overall, the plastic jar trap with large entry area is affordable, durable, and can hold high attractant volumes to maximize D. suzukii capture and selectivity.

Susceptibility of Aphelinus certus (Hymenoptera: Aphelinidae) to neonicotinoid seed treatments used for soybean pest management.

Soybean aphid is an economic pest of soybean in North America. Currently, management of soybean aphid is achieved through the use of foliar- and seed-applied insecticides. However, natural enemies play an important role in regulating soybean aphid populations, and may be adversely affected by insecticides. The effects of imidacloprid and thiamethoxam seed treatments on the soybean aphid parasitoid, Aphelinus certus Yasnosh, were examined using a tritrophic bioassay. A. certus was able to parasitize soybean aphids feeding on imidacloprid- and thiamethoxam-treated plants 5 and 6 wk after planting, respectively. However, up to 10 wk after planting, overall parasitism rates were reduced by 69-88% compared with the control. Therefore, neonicotinoid seed treatments may reduce the effectiveness of A. certus as a natural enemy of soybean aphid in seed-treated crops.

Pheromone-based action thresholds for control of the swede midge, Contarinia nasturtii (Diptera: Cecidomyiidae), and residual insecticide efficacy in cole crops.

The swede midge, Contarinia nasturtii (Kieffer), is an invasive gall midge causing economic damage to cole crops (Brassica oleracea L.) and other crucifers in eastern Canada and United States. An effective decision-making tool for timing insecticide applications is a critical part of an integrated pest management program against C. nasturtii. Experiments were undertaken over 2 yr and at three locations in southern Ontario to develop pheromone-based action thresholds for C. nasturtii in cabbage and broccoli. An economic comparison between action threshold and calendar insecticide regimes was undertaken. The threshold approach was both economically viable and successful at minimizing swede midge damage for cabbage, and an action threshold of five males per trap per day with a minimum 7 d retreatment interval successfully reduced damage to acceptable levels. However, this approach was not successful with broccoli, which, unlike cabbage, is susceptible to damage by C. nasturtii through all plant stages, including heading. Acetamiprid and lambda-cyhalothrin both demonstrated approximately 7 d residual activity against C. nasturtii. Registration labels for both insecticides specify a minimum 7 d retreatment interval, which is supported by residual efficacy results. More effective insecticidal products may have longer residual efficacy and improve efficacy of the action threshold approach for broccoli and cabbage.

Phenology of Bean Leaf Beetle (Coleoptera: Chrysomelidae) in Ontario, Canada and Field Validation of a Degree-Day Model.

The phenology and voltinism of bean leaf beetle, Cerotoma trifurcata (Forster), were examined in three counties in 2010 and two counties in 2011 in Ontario soybean, Glycine max (L.) Merr., fields. Soil samples from within cages containing field-collected beetles revealed one cycle of eggs, larvae, and pupae. Observed degree-day (DD) accumulations for C. trifurcata life stage events (egg hatch, egg hatch to pupation, and oviposition to peak adult) in field experiments were compared with thermal constants determined in a temperature-dependent development laboratory experiment where C. trifurcata were reared under five constant temperatures. Observed and predicted DDs for all life stage events were nearly identical. Mean DD accumulations from first oviposition to peak adult emergence in the field studies was 589 ± 67 DD (base 10.3°C), which was nearly identical to the model prediction (581 ± 40 DD, base 10.3°C).

Swede midge (Diptera: Cecidomyiidae), ten years of invasion of crucifer crops in North America.

The Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), a common insect pest in Europe, is a newly invasive pest in North America that constitutes a major threat to cruciferous vegetable and field crops. Since its first identification in Ontario, Canada, in 2000, it has rapidly spread to 65 counties in the provinces of Ontario and Quebec and has recently been found in canola (one of two cultivars of rapeseed, Brassica napus L. and Brassica campestris L.) in the central Prairie region where the majority of Canada's 6.5 million ha (16 million acres) of canola is grown. The first detection of Swede midge in the United States was in 2004 in New York cabbage (Brassica oleracea L.), but it has now been found in four additional states. Here, we review the biology of Swede midge, its host plant range, distribution, economic impact, pest status, and management strategies. We provide insight into this insect's future potential to become an endemic pest of brassica crops in North America. We also proposed research needed to develop tactics for handling this invasive pest in brassica crops.

Compensatory Abilities of Canola in Response to Swede Midge (Diptera: Cecidomyiidae) Damage.

Swede midge (Contarinia nasturtii Kieffer) is an invasive, economic pest of canola (Brassica napus L.) that threatens production throughout Canada. Swede midge has up to four overlapping generations, placing canola at risk of multiple infestations in the field. The relationship between single and multiple swede midge infestations at different canola stages, and the resulting impacts on yield, are unknown. Laboratory experiments were conducted to evaluate the impact of single and multiple infestations of swede midge on four plant stages of canola: three-leaf, seven-leaf, primary bud, and secondary bud. Previously, the seven-leaf and primary bud stages were considered vulnerable to swede midge, but we determined that the secondary bud stage is also vulnerable. Evidence of compensation by canola in response to herbivory by swede midge was discovered. Compensation occurred mainly through increased production of tertiary racemes and pods and was maximized with exposure of 4.5-6.5 female midges per plant. Although compensation may increase potential yield, it also results in uneven crop maturation resulting in delayed harvest and yield loss. Consequently, to prevent delays in maturation and harvest, insecticides should be applied before these densities are reached.

Synthetic pheromone exposure increases calling and reduces subsequent mating in female Contarinia nasturtii (Diptera: Cecidomyiidae).

BACKGROUND: Pheromone-mediated mating disruption, which uses large amounts of synthetic female pheromones to interrupt insect reproductive behavior, has been successful for managing important agricultural pests. While multiple mechanisms have been discovered explaining how synthetic pheromone treatments prevent males from finding females, it is less clear how unnaturally large doses of synthetic sex pheromone impact the behavior of female insects, particularly nonlepidopteran females. In some species, 'autodetecting' females possess pheromone receptors and respond to ambient pheromones by altering their mating behavior. Here, we test whether exposure to stereospecific and racemic synthetic pheromones influences calling and subsequent propensity to mate in female swede midge (Contarinia nasturtii Kieffer; Diptera: Cecidomyiidae), a pest of Brassica crops. RESULTS: In both laboratory and field settings, females exposed to stereospecific and racemic three-component pheromone blends called significantly more frequently and for longer durations than midges in control treatments. In the field, midges were twice as likely to call in pheromone-treated plots versus nontreated plots. Additionally, pheromone pre-exposure reduced subsequent mating: while 68% of female midges mated following control conditions, only 42% and 35% of females pre-exposed to stereospecific and racemic three-component blends mated, respectively. CONCLUSION: While more frequent calling within pheromone-treated backgrounds may increase the likelihood that females are detected by males, a reduction in female propensity to mate would increase the efficacy of a pheromone-mediated mating disruption system. Our work presents the first known investigation of autodetection behavior in Cecidomyiidae. Additional research is necessary to understand the implications of female autodetection for swede midge management.

Generalist predators (Coleoptera: Carabidae, Staphylinidae) associated with millipede populations in sweet potato and carrot fields and implications for millipede management.

The predatory beetle assemblage of Ontario carrot and sweet potato fields was described and assessed to identify species of interest to the control of the emerging pest millipede Cylindroiulus caeruleocinctus (Wood) (Diplopoda: Julidae). Pterostichus melanarius (Coleoptera: Carabidae) was identified as a dominant species, and seven other carabid species [Pterostichus melanarius (Illiger), Harpalus pensylvanicus (DeGeer), Ophonus puncticeps (Stephens), H. erraticus Say, Bembidion quadrimaculatum oppositum Say, Poecilus chalcites (Say), Scarites subterraneus Fabricius, and Pterostichus permundus (Say)] were identified as common species on the basis of activity density. Common species became more abundant as the growing season progressed. In laboratory bioassays, P. melanarius preyed on millipedes regardless of prey size, whereas H. erraticus never selected millipedes as prey. A significant positive spatiotemporal relationship was found between P. melanarius and C. caeruleocinctus in sweet potato fields. P. melanarius was found to be a natural enemy of C. caeruleocinctus, and other common carabid species warrant future study. The role of Staphylinidae in millipede control could not be elucidated, likely because of low trapping efficiency. Tachinus corticinus Gravenhorst, an introduced staphylinid from Europe, was newly recorded in Ontario, extending its North American range considerably westward from the province of Quebec. The results of this study are an important foundational step toward developing a successful integrated pest management strategy for controlling millipede damage in crops.

Insecticide management strategies for control of swede midge (Diptera: Cecidomyiidae) on cole crops.

Insecticide field trials were conducted in Ontario, Canada, and New York state to identify insecticides effective against the swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), a new invasive pest in North America. Field trials indicated that foliar applications of lambda-cyhalothrin, permethrin, acetamiprid, chlorpyrifos, and dimethoate could provide control of C. nasturtii. Foliar insecticide applications were effective in keeping damage within marketable limits in all cabbage and some broccoli trials during the early phase of regional colonization by C. nasturtii (2001-2002). However by 2005-2006, treatments were rarely able to maintain damage levels within marketable limits. Low efficacy suggested the possibility of insecticide resistance in Canadian C. nasturtii populations, but laboratory assays revealed no evidence for resistance. Thus, eventual control failures on a season-long basis were apparently due to very high populations during later phases of colonization in Ontario. Early season applications (e.g., seed treatments, greenhouse plug tray drenches and/or band sprays) of neonicotinoid insecticides proved effective for 3-5 wk after transplanting in New York. These early season treatments would require supplemental control with foliar insecticides, but would reduce the number of foliar applications required and thus reduce insecticide usage. Our results suggest that acceptable control with foliar insecticides will be difficult where C. nasturtii populations are high, because of multiple and overlapping generations, and difficulty in achieving adequate spray coverage. An integrated pest management program that uses cultural control methods and host plant resistance, with judicious use of insecticides, is needed for sustainable management of this newly invasive pest.

Determining Temperature-Dependent Development and Mortality Parameters of the Swede Midge (Diptera: Cecidomyiidae).

The swede midge (Contarinia nasturtii Kieffer) is an invasive insect in North America whose feeding has caused a decline of over 60% of total canola acreage in Ontario, Canada since 2011. Temperature-dependent development and mortality information are important to develop an effective pest management strategy for this insect; as the most comprehensive study on C. nasturtii development was completed on populations from the United Kingdom in the 1960s, new geographically relevant information is needed. Contarinia nasturtii eggs, larvae, pupae, and adults were reared from wild populations collected from Elora, Ontario, and allowed to develop at different temperatures. Resulting development rates were fit to a series of growth models and the model with the best relative goodness-of-fit was selected to represent the given life stage. Eggs from Ontario populations developed more quickly than their UK counterparts at temperatures below approximately 17°C, but more slowly at temperatures above 17°C. The same phenomenon was observed in larvae at 20°C. Pupae from both populations had similar development rates, and adult longevity was similar as well. This information will inform the management of C. nasturtii, and may help prevent its spread to other canola-producing regions of North America.

Effects of cucumber mosaic virus-infected chilli plants on non-vector Bemisia tabaci (Hemiptera: Aleyrodidae).

Plant virus infections are known to alter host plant attractiveness and suitability for insect herbivores. This study was conducted to determine how cucumber mosaic virus (CMV)-infected chilli plants affect the fitness and settling preferences of nonvector whitefly, Bemisia tabaci adults under dual-choice conditions with volatile organic compounds analyzed using solid phase microextraction coupled with gas chromatography-mass spectrometry (GC-MS). Results showed that the presence of CMV in chilli plants substantially affects the settling preferences of the B. tabaci, which preferred to settle on noninfected plants. Duration of the egg stage and the longevity and fecundity of adult B. tabaci on CMV-infected chilli plants were not markedly different from those on noninfected chilli plants. In contrast, the developmental time from egg to adult was significantly reduced in CMV-infected chilli plants compared to the noninfected plants. The results also showed that CMV-infected chilli plants released significantly more linalool and phenylacetaldehyde than noninfected plants. Overall, it was suggested that the behavioral response of B. tabaci might be modified by CMV-infected plants, which alter the release of specific headspace volatiles. Based on these results, the modification of plant volatile profiles may help in enhancing the effectiveness of biological control and the protection of crop plants against B. tabaci.

Host plant susceptibility to the swede midge (Diptera: Cecidomyiidae).

The relative resistance and susceptibility of various cruciferous plants to swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), damage was investigated to provide growers with planting recommendations and to identify potential sources of resistance to the swede midge. Broccoli cultivars experienced more severe damage than cabbage, cauliflower, and Brussels sprouts. The broccoli 'Paragon', 'Eureka', and 'Packman' are highly susceptible to the swede midge, whereas 'Triathlon' and 'Regal' showed reduced susceptibility to damage and slower development of damage symptoms. No differences were found between normal and red cultivars of cabbage and cauliflower in damage severity and progression of damage symptoms. Four new plant species (Brassica juncea Integlifolia group, Erucastrum gallicum (Willd.) O. E. Shulz., Lepidium campestre (L.) R.Br., and Capsella bursa-pastoris (L.) Medic.) are reported as hosts of the swede midge. The weed species Descurainia sophia (L.) Webb, Camelina microcarpa Andrz. ex Dc., and Erysimum cheiranthoides L. exhibited no damage symptoms, and they seem to be nonhost crucifers for the swede midge.

Reduced Drosophila suzukii Infestation in Berries Using Deterrent Compounds and Laminate Polymer Flakes.

Drosophila suzukii (Matsumura) is a recent invasive pest of soft fruits in North and South America and Europe. Control relies on frequent applications of synthetic insecticides. Additional tactics are needed for development of an effective integrated pest management program. Study objectives were to evaluate the repellency and oviposition deterrent capability of compounds in plant essential oils and the effect of select compounds on infestation rates in strawberries, using laminate polymer flakes as a carrier. Of 14 compounds from 5 essential oils, thymol was the most repellent to adult D. suzukii males and females for up to 24 h in the laboratory. Citronellol, geraniol and menthol were moderately repellent. In a choice assay, thymol on cotton wicks adjacent to ripe raspberries reduced female fly landings and larval infestation levels. In a no-choice assay, thymol reduced female fly landings by 60%, larval infestation by 50% and increased fly mortality compared to controls. Neither citronellol alone nor a blend of four repellent compounds was as effective as thymol alone at reducing fly landing, larval infestation, or increasing fly mortality. In a choice assay using polymer flakes, larval infestation was greater in raspberries near untreated flakes than in raspberries near flakes treated with thymol or peppermint oil. In the field, thymol and peppermint flakes reduced larval infestation levels by 25% in strawberries at 4, but not 7, days after application, compared to untreated flakes. With future improvements in application strategies, deterrent compounds may have a role in improving the management of D. suzukii.

Evaluation of Attractants for Monitoring Drosophila suzukii (Diptera: Drosophilidae).

Drosophila suzukii Matsumura is an economically important pest of soft and small fruit crops. Unlike other drosophilid flies, D. suzukii is capable of infesting ripe and partially ripe fruit, which poses a significant pest management challenge, as there is no tolerance for infested or damaged fruit in the marketplace. As a result, producers in many regions rely on calendar-scheduled insecticide applications for D. suzukii management. In order to develop an integrated pest management approach, better tools for monitoring adult fly populations are needed. Over two growing seasons in southern Ontario, we evaluated three commercial (Pherocon SWD dual-lure, Suzukii Trap, and Scentry Lure) and two homemade baits (apple cider vinegar and yeast + sugar water) for their ability to capture D. suzukii in raspberry and highbush blueberry fields. In general, commercial attractants captured D. suzukii earlier in the growing season and in greater numbers, with fewer nontarget captures, compared with homemade baits. Scentry Lure tended to perform better than other attractants, capturing D. suzukii earlier and in larger numbers during peak harvest. Pherocon SWD dual-lure was highly specific to D. suzukii. The combination of Scentry Lure with Suzukii Trap had possible synergistic effects, as numbers of D. suzukii captured to the combined treatment were more than additive. Using commercial attractants improves D. suzukii monitoring and will allow growers to improve the timing of insecticide applications with D. suzukii activity in the field.

Efficacy of Biopesticides for Management of the Swede Midge (Diptera: Cecidomyiidae).

Management of the swede midge, Contarinia nasturtii Kieffer, in North American crucifer production relies on crop rotation and the timely application of synthetic insecticides, based on pheromone trap monitoring of local adult populations. Organically acceptable formulations of azadirachtin, pyrethrin, and spinosad, and a commercial biopesticide containing the entomopathogenic fungus, Beauveria bassiana, were evaluated for their effects on larval mortality and oviposition deterrence in the greenhouse, and on damage symptoms in the field. In greenhouse trials, pyrethrin and spinosad treatments applied up to 24 h prior to C. nasturtii exposure resulted in significant reductions in oviposition on host plants, whereas azadirachtin and B. bassiana only deterred oviposition when applied 2 h prior to exposure. Spinosad caused the highest larval reduction (∼96%) on cauliflower meristems, while azadirachtin, B. bassiana, and pyrethrin caused significant larval reduction when applied preoviposition and significant mortality when applied postoviposition. Field trials conducted with these insecticides on broccoli in 2011 produced no significant reductions in overall damage levels; however, B. bassiana treatments produced more marketable plants than did the control. In 2013, all treatments significantly reduced overall damage levels and all treatments, except B. bassiana, produced more uninfested and marketable plants than the control. Field applications of these alternative insecticides may be effective in protecting yields of broccoli and cauliflower, when combined with other tactics in an integrated pest management program.

Plant essential oils and potassium metabisulfite as repellents for Drosophila suzukii (Diptera: Drosophilidae).

Spotted wing drosophila, Drosophila suzukii, is a globally invasive pest of soft-skinned fruit. Females oviposit into ripening fruit and larvae cause direct destruction of tissues. As many plant essential oils are permitted food additives, they may provide a safe means of protecting fruit from D. suzukii infestation in both conventional and organic production systems. Twelve oils and potassium metabisulfite (KMS) were screened in the laboratory as repellents for D. suzukii flies. Most essential oils deterred D. suzukii flies from cotton wicks containing attractive raspberry juice. Peppermint oil was particularly effective, preventing almost all flies from contacting treated wicks and remaining 100% repellent for 6 d post-application. Thyme oil was unique because it caused high male mortality and reduced the number of responding flies compared to other oils. KMS was not found to be repellent to D. suzukii, but may have fumigant properties, particularly at high concentrations. Peppermint oil appears to be the best candidate for field testing to determine the effectiveness and feasibility of using essential oils as part of a push-pull management strategy against D. suzukii. This is the first time that essential oils have been evaluated and proven effective in preventing fruit-infesting flies from contacting attractive stimuli.