We provide recommendations for sampling and identification of introduced larval parasitoids of spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). These parasitoids are either under consideration for importation (aka classical) biological control introductions, or their adventive (presumed to have been accidentally introduced) populations have recently been discovered in North America and Europe. Within the context of the ecology of D. suzukii and its parasitoids, we discuss advantages and disadvantages of estimating larval parasitism levels using different methods, including naturally collected fruit samples and sentinel baits. For most situations, we recommend repeated sampling of naturally occurring fruit rather than using sentinel baits to monitor seasonal dynamics of host plant–Drosophila–parasitoid associations. We describe how to separate Drosophilidae puparia from host fruit material in order to accurately estimate parasitism levels and establish host–parasitoid associations. We provide instructions for identification of emerging parasitoids and include a key to the common families of parasitoids of D. suzukii. We anticipate that the guidelines for methodology and interpretation of results that we provide here will form the basis for a large, multi-research team sampling effort in the coming years to characterize the biological control and nontarget impacts of accidentally and intentionally introduced larval parasitoids of D. suzukii in several regions of the world.

Caneberries are trellised to facilitate harvest and agrochemical applications as well as to improve crop yield and quality. Trellising can also increase airflow and light penetration within the canopy and affect its microclimate. We compared an experimental trellis that split the canopy into halves to standard I- and V-trellises, measuring Drosophila suzukii (Matsumura) fruit infestation as well as canopy temperature and relative humidity in raspberries at two commercial you-pick diversified farms. To evaluate the combined effects of trellising systems and pruning, we pruned one half of each row in blackberry plantings at two research farms and assessed D. suzukii infestation, canopy microclimate (temperature, relative humidity, and light intensity), fruit quality parameters (interior temperature, total soluble solids, and penetration force), and spray coverage/deposition. Trellis installation costs, labor inputs, and yield were used to further evaluate the trellis systems from an economic perspective. Fruit quality was not affected by trellising or pruning and lower total yield was observed in the experimental trellis treatment on one farm. Although D. suzukii infestation was only affected by trellising and pruning at one site, we observed a relationship between higher temperatures and reduced infestation on nearly all farms. Occasionally, lower relative humidity and high light intensity corresponded with lower infestation. Ultimately, the experimental trellis was less economically efficient than other trellising systems and our ability to successfully manipulate habitat favorability varied in a site-specific manner. Drosophila suzukii management approaches that rely upon unfavorable conditions are likely to be more effective in hot, dry regions.

Essential oils (EOs) produced by plants in the Lamiaceae family may provide new insecticidal molecules. Novel control compounds are needed to control Drosophila suzukii (Matsumura), a severe economic invasive pest of thin-skinned fruit crops. Thus, we characterized the main compounds of EOs from three rosemary Rosmarinus officinalis ecotypes (ECOs) and evaluated their toxicity to D. suzukii adults, deterrence of oviposition behavior, and histological alterations in larvae. Additionally, we analyzed the lethal and sublethal effect on the pupal parasitoid Trichopria anastrephae. The main compounds identified in the R. officinalis ECOs were α-pinene, camphor and 1,8-cineole. In bioassays via topical application or ingestion, ECOs and their major compounds showed high toxicity on D. suzukii adults and a lower concentration could kill 50% and 90% of flies compared to spinetoram. The dry residues of a-pinene, 1,8-cineole, and camphor provided a repellent effect by reducing D. suzukii oviposition by ∼47% compared to untreated fruit. Histological sections of 3^rd instar larval D. suzukii posttreatment revealed damage to the fat body, Malpighian tubules, brain, salivary gland, and midgut, which contributed to high larval and pupal mortality. Survival and parasitism by adult T. anastrephae were not affected. Thus, R. officinalis EO and their compounds have potential for developing novel insecticides to manage D. suzukii.

Drosophila suzukii (Matsumura 1931) represents one of the main pests of small fruits. The use of biological agents is very promising for insect control. In the present study, the nematode Steinernema rarum PAM 25 was evaluated for the control of D. suzukii pupae, this species has not been evaluated previously. First, we evaluated the pathogenicity of S. rarum PAM 25 at the concentration of 1,000 infective juveniles (IJs) inoculated into D. suzukii pupae. In the second bioassay, we evaluated the influence of 1,500; 2,000; 2,500; 3,000; 4,000 IJs/ml nematode concentration and temperature on D. suzukii mortality. In the third bioassay, we evaluated the influence of the isolate S. rarum PAM 25 on D. suzukii adult lifespan following pupal infection, using the concentrations with the highest mortality rate of pupae at each temperature as determined in the second experiment. The S. rarum PAM 25 isolate is pathogenic to D. suzukii. The most effective temperature for S. rarum PAM 25 activity was 14°C at a concentration of 4,000 IJs/ml. Adults infected with S. rarum PAM 25 showed a significant reduction in longevity. The results confirmed the potential of S. rarum PAM 25 for the control of D. suzukii.

Spinosyn insecticides are widely used in conventional berry production, and spinosad is regarded as the most effective insecticide for managing Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), spotted-wing drosophila, in organic berry crops. Following the 2017 identification of spinosad resistance in caneberry fields in the Watsonville area, Santa Cruz Co., California, we conducted a study to examine the seasonal and annual susceptibility of D. suzukii over a three-year period. Adult flies were collected from two conventional and two organic caneberry fields in the Monterey Bay region, California, at ‘early’, ‘middle’, and ‘late’ time points during the 2018–2020 growing seasons, and their susceptibility to spinosad was assessed. Results demonstrated that spinosad susceptibility in the D. suzukii field populations generally decreased during the fruit production season (from June through November), and over consecutive seasons. LC₅₀ values of adults from the conventional sites were determined to be as high as 228.7 mg l^–1 in 2018, 665.6 mg l^–1 in 2019, and 2700.8 mg l^–1 in 2020. For the organically managed fields, LC₅₀s of adults were as great as 300.0 mg l^–1 in 2018, 1291.5 mg l^–1 in 2019, and 2547.1 mg l^–1 in 2020. Resistance ratios based on the LC₅₀ values were as high as 10.7-, 13.2-, and 16.9-fold in 2018, 2019, and 2020, respectively. These results should serve as a caution for growers in other production areas, facilitate informed choice of insecticides used in D. suzukii management, and emphasize the need to develop effective insecticide resistance management strategies for this insect.

In the continental United States, the invasive spotted-wing drosophila (SWD), Drosophila suzukii Matsumura, has become a primary pest of multiple stone and soft-skinned fruits. A new innovative adjuvant formulation, ACTTRA SWD, mixed with a suitable insecticide, constitutes a novel attract-and-kill tactic to manage D. suzukii in fruit crops. We hypothesized that background odors present in crop fields, particularly odors from host fruits, negatively affect the effectiveness of this attract-and-kill formulation, as odors from these sources can compete for insect attraction. Additionally, we evaluated the influence of adult D. suzukii sex and physiological status (age and mating status), and fruit ripeness on its response to the ACTTRA SWD formulation. For this, we used two-choice bioassays to test the response of adult D. suzukii to three ACTTRA SWD formulations (named OR1, TD, and HOOK SWD) in the presence and absence of host fruits (blueberries, raspberries, blackberries, and strawberries). Odors from raspberries were significantly more attractive than those from the TD formulation mixed with spinosad (Entrust). For the HOOK SWD formulation and OR1+Entrust formulation, odors from all the fruit types tested were significantly more attractive than the adjuvants. Compared with females, male D. suzukii were more attracted to the TD formulation over the blueberry fruits. Additionally, age and female mating status but not fruit ripeness influenced D. suzukii attraction to both OR1 and TD formulations. The results from this study indicate that D. suzukii physiological status and host fruit availability impact the efficacy of new attract-and-kill adjuvants such as ACTTRA SWD.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a ubiquitous global pest of several fruit crops. Trapped adult numbers are used to monitor populations and make control decisions, but differentiating D. suzukii from other trapped Drosophila spp. is laborious. We developed a real-time PCR method for specific detection and semi-quantification of D. suzukii from trap samples. The PCR assay did not amplify DNA from 29 other Drosophilidae species tested. Drosophila suzukii was detected from ≥0.96 pg target DNA and from laboratory samples containing one D. suzukii in 2000 other Drosophila spp. flies. We tested DNA stability of one D. suzukii in 100 Drosophila spp. flies in water or ethanol at 20, 25, or 30°C for 1, 4, or 7 d. Only water at 30°C for 7 d fully impaired D. suzukii DNA detectability. Substituting mouthwash for water resulted in D. suzukii detection in all samples held for 7 d at 30°C or daily fluctuating temperatures of 33/23°C. Traps with mouthwash as a drowning liquid had D. suzukii captures equal to traps with water. A calibration curve was established using samples in mouthwash containing 1/1,000—100/1,000 D. suzukii/total Drosophila spp. flies and incubated at 25°C for 7 d. The curve had a coefficient of determination (R²) of 0.9279 between D. suzukii numbers from the PCR and the true D. suzukii numbers in samples prepared in 70% ethanol. Collecting samples in mouthwash is expected to improve detection accuracy, and the qPCR method can be a useful tool to support D. suzukii monitoring and management.

Since the early phase of the intercontinental dispersal of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), fermentation baits have been used for monitoring. Self-made lures and commercial products are often based on wine and vinegar. From an ecological perspective, the formulation of these baits is expected to target especially vinegar flies associated with overripe fruit, such as Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). Hanseniaspora uvarum (Niehaus) (Ascomycota: Saccharomyceta) is a yeast closely associated with D. suzukii and fruit, and furthermore attractive to the flies. Based on this relation, H. uvarum might represent a suitable substrate for the development of lures that are more specific than vinegar and wine. In the field, we therefore, compared H. uvarum to a commercial bait that was based on vinegar and wine with respect to the number of trapped D. suzukii relative to other drosophilids and arthropods. Trap captures were higher with the commercial bait but specificity for D. suzukii was greater with H. uvarum. Moreover, H. uvarum headspace extracts, as well as a synthetic blend of H. uvarum volatiles, were assayed for attraction of D suzukii in a wind tunnel and in the field. Headspace extracts and the synthetic blend induced strong upwind flight in the wind tunnel and confirmed attraction to H. uvarum volatiles. Furthermore, baited with H. uvarum headspace extract and a drowning solution of aqueous acetic acid and ethanol, 74% of field captured arthropods were D. suzukii. Our findings suggest that synthetic yeast headspace formulations might advance the development of more selective monitoring traps with reduced by-catch.

Spotted-wing drosophila, Drosophila suzukii Matsumura, was first established in Latin America in Mexico in 2011. The vinegar fly has since been detected in 296 municipalities in Argentina, Brazil, Chile, Mexico, and Uruguay. Drosophila suzukii is polyphagous and is found on 64 host plants in 25 families in Latin America, with most hosts also exotic species. In Latin America, D. suzukii is attacked by 14 species of parasitoid wasps in the families Diapriidae, Figitidae, and Pteromalidae, which are promising native parasitoids for control of the pest. This article analyzes results from studies on monitoring, biological, chemical, and cultural control, and sterile insect techniques to provide a basis for the development of area-wide and sustainable D. suzukii management programs in Latin America. The review examines how D. suzukii has been managed in Latin America and how research conducted in this region can contribute to management of the species in other parts of the world.

Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) is a vinegar fly native to East Asia that has rapidly expanded its range to become a pest of sweet cherry (Prunus avium, L. 1753 [Rosales: Rosaceae]) and tart cherry (P. cerasus, L. 1753) in North America and Europe. The goal of the research presented herein was to improve the decision-making process for managing D. suzukii in tart cherry. Knowing that D. suzukii females are attracted to ripening fruit, we measured fruit infestation by D. suzukii as it relates to an existing fruit development model that uses full bloom as a biofix, calculating accumulated growing degree days (GDD) with a lower threshold of 4°C. Increasing larval infestation was highly correlated with fruit development expressed as GDD post-bloom with very few larvae developing in fruit subjected to no-choice assays prior to 530 GDD (base 4°C) and no larvae detected in naturally infested fruit prior to 800 GDD. Our findings provide the first quantification of the relationship between fruit development and D. suzukii infestation that allows for pinpointing the timing of fruit susceptibility and that could be used as the basis for a more sustainable management program for this pest in tart cherry orchards.

Massive economic damage by spotted-wing drosophila (SWD), Drosophila suzukii, results from their unique egg laying behavior wherein a gravid fly pierces a ripening fruit to lay a number of eggs. Gravid SWD flies employ a complex suite of behaviors to find a fruit with the optimum firmness and chemistry. We investigated chemosensory cues potentially contributing to the oviposition behavior of SWD. In a series of experiments, we studied how the fruit ripeness and the underlying volatile chemistry influence oviposition. We tested the comparative attraction of three common fruits implicated in oviposition and determined raspberries to be most attractive in the trap choice assays that strictly measured olfactory preference. Since SWD oviposit in ripening fruits and appear to avoid the overripe fruit, we further evaluated the effect of ripeness on gravid fly attraction. Overripe fruits were significantly more attractive compared to the ripe fruits. The trap choice assays were repeated in an olfactory T-maze paradigm that provided a complex odor environment, potentially experienced by the gravid flies, and the results were mostly comparable. Since our behavioral paradigms indicated a clear olfactory preference for specific ripeness stages (ripe and overripe), we analyzed the constituent volatile odorants from the three ripening stages, revealing discrete odor profiles. Finally, we quantified the total soluble sugars and carbon dioxide concentrations from field-collected raspberries in underripe, ripe, and overripe conditions, revealing that the overripe stage is the most sugar-rich. Together, our results indicate unique chemosensory adaptations in gravid SWD flies for successfully exploiting optimal oviposition resources.

Monitoring is an important element in management programs for Drosophila suzukii (Matsumura), helping users to avoid prophylactic treatments. Factors such as attractiveness, sensitivity, selectivity, longevity, and ease of use must be considered when developing a trap and lure system for monitoring and thresholds. We examined various baits and lures over a 5-yr period in sweet cherry orchards in the semiarid climate of eastern Washington. Using a jar trap, the attractants were evaluated for attractiveness (maximum capture), selectivity for D. suzukii (vs. other Drosophila species), and sex ratio of captured D. suzukii. We examined the relative performance of the attractants during periods of low (≈1 D. suzukii per trap per week) and high (232 D. suzukii per trap per week) density over the course of the growing season, which usually corresponded to mid-summer and autumn temperatures, respectively. The Scentry lure was consistently the most attractive lure, capturing the highest numbers of adult D. suzukii over the series of tests, but also had the highest levels of by-catch. Recipe-based baits (yeast, wine-vinegar, and apple cider vinegar) captured fewer D. suzukii overall, although the commercial baits Dros'Attract and Suzukii Trap were comparable to the Scentry lure in late season tests. The Trécé lures were consistently the most selective of the attractants, but had generally lower D. suzukii captures. Sex ratio varied widely among and within the tests, but with no consistent pattern among the various attractants. All attractants were successful in capturing flies, and the choice of attractant depends on the constraints and goals of the user.

Drosophila suzukii (Matsumura) has spread rapidly, challenging berry and cherry crop production due to its ability to lay eggs into ripening fruit. To prevent infestation by this pest, insecticides are applied during fruit ripening and harvest. We field-tested the Rapid Assessment Protocol for IDentification of resistance in D. suzukii (RAPID) on seventy-eight populations collected across eight U.S. states in 2017 and 2018. Exposure to LC₅₀ rates of malathion, methomyl, spinetoram, spinosad, and zeta-cypermethrin led to average female fly mortality of 25.0% in 2017, and after adjusting concentrations the average was 39.9% in 2018. Using LC₉₉ × 2 discriminating concentrations in 2017 and LC₉₀ × 8 rates in 2018, average female mortalities were 93.3% and 98.5%, respectively, indicating high overall susceptibility. However, using these high concentrations we found 32.0% of assays with survival of some female flies in 2017 and 27.8% in 2018. The adjustment in discriminating dose from 2017 to 2018 also reduced the proportion of assays with <90% survival from 17.6 to 2.9%. Populations with low mortality when exposed to spinosad were identified using this assay, triggering more detailed follow-up bioassays that identified resistant populations collected in California coastal region berry crops. Widespread evaluations of this method and subsequent validation in California, Michigan, and Georgia in 2019–2021 show that it provides a quick and low-cost method to identify populations of D. suzukii that warrant more detailed testing. Our results also provide evidence that important insecticide classes remain effective in most U.S. regions of fruit production.

Indoor storage of honey bees (Apis mellifera L.) during winter months has been practiced for decades to protect colonies from the adverse effects of long, harsh winter months. Beekeepers have recently employed indoor storage to reduce labor, feeding costs, theft, and woodenware degradation. Despite the growing number of colonies stored indoors, national survey results still reveal high losses. Varroa mites (Varroa destructor Anderson and Trueman) are the most critical threat to colony winter survival and health of colonies because they contribute to the transmission of viruses and colony mortality. To investigate the effect of high CO₂ on varroa mites during the indoor storage of honey bees, 8-frame single deep colonies were stored in two separate environmental chambers at 4°C each. One environmental chamber was set at 8.5% CO₂ (high CO₂), while the other was set at low CO₂ (0.12%). Dead and falling mites were collected and counted from the bottom of individual colonies weekly during the experiment. There was a significant difference in mite mortality of colonies with high CO₂ compared to colonies held at low CO₂. These results indicated that high CO₂ could increase mite mortality during the period of indoor storage, potentially improving honey bee health coming out of the winter months. Our research offers a critical addition to beekeepers' tools for managing varroa mite populations.

The soybean aphid (Aphis glycines Matsumura) is an economically important invasive pest of soybean. In addition to damage caused by soybean aphid feeding on the phloem sap, this insect also transmits many plant viruses, including soybean mosaic virus (SMV). Previous work has shown that plant viruses can change plant host phenotypes to alter the behavior of their insect vectors to promote virus spread, known as the vector manipulation hypothesis. In this study, we used electropenetography (EPG) to examine the effects of two plant viruses on soybean aphid feeding behavior: SMV, which is transmitted by many aphid species including the soybean aphid, and bean pod mottle virus (BPMV), which is transmitted by chrysomelid and some coccinellid beetles but not aphids. These two viruses often co-occur in soybean production and can act synergistically. Surprisingly, our results showed little to no effect of SMV on soybean aphid feeding behaviors measured by EPG, but profound differences were observed in aphids feeding on BPMV-infected plants. Aphids took longer to find the vascular bundle of BPMV-infected plants, and once found, spent more time entering and conditioning the phloem than ingesting phloem sap. Interestingly, these observed alterations are similar to those of aphids feeding on insect-resistant soybean plants. The cause of these changes in feeding behavior is not known, and how they impact virus transmission and soybean aphid populations in the field will require further study.

Aboveground and belowground herbivory can alter host quality and trophic interactions. However, little research has explored the impacts of belowground herbivory on plant virus epidemiology. To understand this interaction in sweetpotato, Ipomoea batatas L. (Lam), we studied the impact of herbivory by sweetpotato weevil, Cylas formicarius elegantulus (Summers), to storage roots on vector herbivore, Myzus persicae (Sulzer), the green peach aphid, and Aphis gossypii Glover, the cotton aphid, feeding behavior (M. persicae and A. gossypii) and population dynamics (M. persicae only as A. gossypii does not colonize sweetpotato). In addition, a nonvector herbivore, Chrysodeixis includens (Walker), the soybean looper, weight gain was included for comparison. Infestations of sweetpotato weevil in storage roots reduced C. includens weight gain and M. persicae intrinsic rate of increase (r_m), net reproductive rate (R_o), and finite rate of increase (λ) on aboveground portions of the plant. In probing behaviors related to nonpersistent virus spread (30 min trials), M. persicae probed less often, took longer to reach the first pd (potential drop), had shorter II-3 (intracellular subphase sap ingestion) durations, and had fewer archlets on plants infested with C. formicarius elegantulus. Total phloem duration did not differ between treatments, indicating that the lowered performance of M. persicae on infested plants was not due to discrepancies in probing duration. Results were less clear for A. gossypii. Thus, in sweetpotato, belowground herbivory can alter plant virus vector abundance and behavior. Understanding the mechanisms underlying these changes in behavior could improve plant virus vector integrated pest management.

Studies addressing the economic impacts of invasive alien species are biased towards ex-post assessments of the costs and benefits of control options, but ex-ante assessments are also required to deal with potentially damaging invaders. The polyphagous shot hole borer Euwallacea fornicatus (Coleoptera: Curculionidae) is a recent and potentially damaging introduction to South Africa. We assessed the potential impact of this beetle by working across economic and biological disciplines and developing a simulation model that included dynamic mutualistic relations between the beetle and its symbiotic fungus. We modeled the potential growth in beetle populations and their effect on the net present cost of damage to natural forests, urban trees, commercial forestry, and the avocado industry over 10 yr. We modeled high, baseline, and low scenarios using discount rates of 8, 6, and 4%, and a plausible range of costs and mortality rates. Models predicted steady growth in the beetle and fungus populations, leading to average declines in tree populations of between 3.5 and 15.5% over 10 yr. The predicted net present cost was 18.45 billion international dollars (Int. $), or about 0.66% of the country's GDP for our baseline scenario ($2.7 billion to $164 billion for low and high scenarios). Most of the costs are for the removal of urban trees that die as a result of the beetle and its fungal symbiont, as has been found in other regions. We conclude that an ex-ante economic assessment system dynamics model can be useful for informing national strategies on invasive alien species management.

Phytoseiid predatory mites are efficient biocontrol agents of important thrips pests, such as the western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae). Until recently, it was believed that first instars, and to a lesser extent second instars, were the most vulnerable developmental stages of thrips to be attacked by phytoseiids. However, recent evidence showed that some phytoseiids can detect and prey upon thrips eggs inserted in the leaf tissue. As phytoseiid predatory mites often co-occur with other beneficial insects, such as mirid and anthocorid predatory bugs which also insert their eggs inside leaf material, this raises the question whether phytoseiid predatory mites may also feed on predatory bug eggs. Here we first tested the potential of Amblyseius swirskii Athias-Henriot, Transeius montdorensis Schicha, and Amblydromalus limonicus Garman and McGregor (Acari: Phytoseiidae) to kill eggs of F. occidentalis in leaf tissue. Secondly, we tested whether those phytoseiids were capable of killing eggs of Orius laevigatus Fieber (Hemiptera: Anthocoridae), Macrolophus pygmaeus Rambur and Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae), three biocontrol agents that also insert their eggs inside plant tissue. Our results showed that A. swirskii and A. limonicus could kill thrips eggs, whereas T. montdorensis could not. Furthermore, we show that the presence of phytoseiid predatory mites does not affect the hatch rate of predatory bugs that insert their eggs inside leaves.

Parasitoid wasps are invaluable agents in pest biological control. Early detection and identification of parasitoid immatures are vital in characterizing parasitoid–host interactions and for evaluating parasitism rates accurately in the field. Trichogramma is the most widely used parasitoid wasp, and several studies have been performed for its molecular identification. However, those studies were mainly focused on Trichogramma adults and rarely on immatures. Here, we report a method to detect and identify Trichogramma larvae in their host eggs. We designed a pair of Trichogramma-specific primers that amplified Trichogramma mtCOI sequences from Corcyra cephalonica (Stainton) eggs parasitized by any of eight Trichogramma species tested but not from nonparasitized eggs of four lepidopteran hosts. This PCR method reliably detected Trichogramma immatures in parasitized eggs as early as 1 h after parasitism. We further developed an RFLP (restriction fragment length polymorphism) assay using restriction enzymes SspI and VspI to differentiate eight Trichogramma species at their immature stage. Overall, we developed a sensitive and reliable PCR–RFLP method to detect and identify immature-stage Trichogramma in their lepidopteran hosts. This method shows promise for conveniently identifying Trichogramma in insectaries and accurately evaluating parasitism rates in the field.

Gut microbiota play an important role in digestion, development, nutritional metabolism, and detoxification in insects. However, scant information exists on the gut bacterial variation, composition, and community structure of the beet armyworm, Spodoptera exigua (Hübner), and how its gut microbiota has adapted to different geographical environments. Using 16S rRNA high-throughput sequencing technology, we detected 3,837,408 high-quality reads and 1,457 operational taxonomic units (OTUs) in 47 gut samples of S. exigua collected from ten sites in northern China. Overall, we identified 697 bacterial genera from 30 phyla, among which Proteobacteria and Firmicutes were the most dominant phyla. Gut bacterial alpha-diversity metrics revealed significant differences among these populations. We detected the highest alpha bacterial diversity in Xinming, northern Liaoning Province, and the lowest bacterial diversity in Zhangwu, western Liaoning Province. Beta diversity indicated that the gut microbial community structure of S. exigua in Liaoning Province was significantly different from that of other populations. There was a similar microbial community structure among populations in the adjacent province, suggesting that the environment influences bacterial succession in this pest. Finally, PICRUSt analysis demonstrated that microbial functions closely associated with the gut microbiomes mainly included membrane transport, carbohydrate metabolism and replication, and amino acid metabolism.

Graphical Abstract

In this work, we found that significant differences in the community structure of the BAW gut microbiota between Liaoning and other populations

A systems approach was developed as an alternative to a standalone quarantine disinfestation treatment for Thaumatotibia leucotreta in citrus fruit exported from South Africa. The systems approach consists of three measures: pre and postharvest controls and measurements, postpacking inspection, and postharvest exposure to low temperatures. Different cold treatment conditions with a range of efficacy levels can be used for this last measure. A series of trials reported here evaluated the efficacy of seven temperatures ranging from 0 to 5°C for durations from 14 d to 26 d. Mortality of the most cold-tolerant larval stages of T. leucotreta was determined. Temperatures of 0, 1, 2, and 3°C for 16, 19, 20, and 24 d respectively, induced 100% mortality of the tested populations. Probit 9 level treatment efficacy was achieved at 0 and 1°C for 16 and 19 d respectively. Mortalities higher than 90% were obtained with temperatures of 4, 4.5, and 5°C, after exposure for the longer durations. We demonstrated a significant difference in cold-induced insecticidal efficacy between 1, 2, 3, and 4°C. There was no significant difference in insecticidal efficacy between 4 and 4.5°C, but both of these temperatures were more efficacious than 5°C. The results of this study are valuable to support the use of cold treatment conditions with lower risk of fruit chilling injury in an effective systems approach, where the cold treatment efficacy can be augmented with other components of the systems approach.

Insect general odorant-binding proteins (GOBPs) play irreplaceable roles in filtering, binding, and transporting host odorants to olfactory receptors. Grapholita funebrana (Treitscheke) (Lepidoptera: Tortricidae), an economically important pest of fruit crops, uses fruit volatiles as cues to locate host plants. However, the functions of GOBPs in G. funebrana are still unknown. Three GOBP genes, namely, GfunGOBP1, GfunGOBP2, and GfunGOBP3, were cloned, and their expression profiles in different tissues were detected by the method of real-time quantitative PCR (RT-qPCR). The binding properties of recombinant GfunGOBPs (rGfunGOBPs) to various ligands were investigated via fluorescence binding assays. The three GfunGOBPs were mainly expressed in the antennae of both male and female moths. All these three rGfunGOBPs could bind to sex pheromones, while having varying affinities toward these pheromones. The three rGfunGOBPs also displayed a wide range of ligand-binding spectrums with tested host odorants. The rGfunGOBP1, rGfunGOBP2, and rGfunGOBP3 bound to 34, 33, and 30 out of the 41 tested odorants, respectively. Three rGfunGOBPs had overlapping binding activities to β-myrcene, (-)-α-phellandrene, and ethyl isovalerate with the K_i less than 3.0 µM. The rGfunGOBP1 and rGfunGOBP3 could selectively bind to several insecticides, whereas rGfunGOBP2 could not. Three rGfunGOBPs had the dual functions of selectively binding to sex pheromones and host odorants. Moreover, the rGfunGOBP1 and rGfunGOBP3 can also serve as ‘signal proteins’ and bind to different insecticides. This study contributed to elucidating the potential molecular mechanism of the olfaction for G. funebrana, and thereby promotes the development of effective botanical attractants or pheromone synergists to control G. funebrana.

Graphical Abstract

Spodoptera frugiperda (J.E. Smith) is a severe and fast-spreading pest of numerous agro-economic crops, including miscellaneous, vegetables, and green manure crops. Understanding pest ecology represents a core component in integrated pest management decision-making. In Taiwan, peanut (Arachis hypogaea L.) is an important miscellaneous crop, whereas sesbania (Sesbania roxburghii Merr.) is the most frequently used green manure crop. To improve the S. frugiperda management in Taiwan, the demographic characteristics and population simulation of this pest reared on peanut and sesbania leaves were analyzed using the age-stage, two-sex life table theory. The intrinsic rate of increase, finite rate of increase, and net reproductive rate of S. frugiperda were higher when reared on peanut (0.1625 d^–1, 1.1764 d^–1, 264.9 offspring) than on sesbania (0.0951 d^–1, 1.0997 d^–1, and 30.3 offspring). Population projection of S. frugiperda on peanut demonstrated that this crop is a more suitable host plant than sesbania.Yet, this suboptimal host still assures an increasing trend of more than 357-fold individuals in 75 d, from the initial cohort of 10 eggs. Our data suggest that green manure plants in fallowing fields may support the pest's survival all year round, and may be responsible for a successful establishment and unexpected outbreaks of this invasive pest on the neighboring crops inTaiwan. Our study thus highlights the importance of assessing the population dynamics and areawide pest management of an invasive polyphagous pest on a noneconomic crop to mitigate the potential risk of reinfestation and thus outbreaks.

Alphitobius diaperinus is one of the most significant pests in the poultry industry. Identifying the role of self-produced chemical signals can help control it. Here, we exposed adults to the olfactory signals of other adults of similar and different genders (either males or females) and sexual experiences (i.e., virgin and experienced) to assess their long-range attractiveness and, at short-range, their mating behavior responses (i.e., touching, mounting, and copulation). In olfactometric experiments, our results indicate that adults are attracted to the olfactory signals of other male adults, independently of gender, or sexual condition, indicating the presence of generalized long-range attractive signals, in contrast to female signals, can be both factor-dependent. However, in mating experiments, virgin males developed more robust mating responses (i.e., they mount and copulate longer with females) compared to sexually experienced males, even though they both have similar precopulatory behavioral responses (i.e., time of antennal and leg touching). These results address the importance of short-range chemical signals in eliciting copulation. Furthermore, when virgins of both genders were tested, their mating responses were significantly longer than any other pair combination, indicating that sexual experience also affects mating behavior. Chemical analyses of adult extracts showed that sexual experience, but not gender, is linked to differences in chemical profiles of adults, primarily involved in short-range signaling. These findings provide new insights into the attractiveness and mating responses of A. diaperinus and the role of sexual experience in shaping the behavior and chemical profile of insects that mate multiple times during their lifetime.

One of the most economically important pests of cotton, Gossypium hirsutum L., in the midsouth region of the United States is the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois, Hemiptera: Miridae). Tarnished plant bug populations across the region have exhibited widespread resistance to numerous insecticide classes. To minimize late season resistance development, reducing unwarranted applications during the late flowering period can aid in resistance management and potentially reduce input costs. Trials were conducted during 2019 and 2020 to evaluate the impacts of tarnished plant bug populations in the later flowering period of cotton by modifying or terminating threshold regimes during the later weeks of bloom. Results showed that dynamic thresholds altered at the fourth week of bloom or later can reduce the number of late season applications made with no penalty to yield. Additionally, when utilizing a week of bloom termination approach, no significant yield losses were seen when terminating applications after the fourth week of bloom. These data may offer an alternative method to managing tarnished plant bug populations during the later flowering period of midsouth cotton.

The alfalfa leafcutting bee Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae) is the primary pollinator for the alfalfa seed industry. It is a solitary cavity nesting bee that utilizes leaf lined brood cells provisioned with pollen for larval development and pupation into the adult stage. During development, multiple pathogens, parasitoids, and predators can prey upon or use the larvae as a host, resulting in the loss of the future adult bee. As such, the presence of invertebrate pests and fungal pathogens presents a major concern for commercial alfalfa seed growers. In the present study, we used historic data from the Parma Cocoon Diagnostic Laboratory to determine baseline rates of pathogens, parasitoids, and predators of Megachile rotundata brood cells and used this analysis to determine cutoffs for management practices to inform growers when the purchase of new bee stocks should be considered. Additionally, we compared the presence of chalkbrood, predators, and parasitoids in samples collected from both grower-produced stocks and newly purchased Canadian bees. The results of the investigation provide historic averages of the presence of chalkbrood, predators, and parasitoids, show a significant increase in chalkbrood and predators in 2007–2011, and find a significant difference in rates of chalkbrood and predators between samples from Canadian suppliers and grower stocks. We speculate that these differences may have resulted from economic conditions that increased the cost of Canadian Megachile rotundata cells and likely resulted in increased reliance on 2nd-year U.S. grower stocks and subsequently increased infection rates during this time period.

Relative to fallow-cash crop rotations, the addition of a cover crop can contribute to greater plant diversity and has the potential to conserve predatory arthropods. The transition of arthropods from a cover crop to a subsequent cash crop depends on several factors, such as cover crop biomass production and weather conditions. Information about the effect of cover crop planting and termination dates on arthropods in a subsequent corn system is limited. A two-year field study was conducted in Nebraska in 2018/2019 and 2019/2020 to evaluate the impact of cover crop planting and termination dates as a source for arthropods in the subsequent corn. A total of 38,074 and 50,626 arthropods were collected in the first and second year, respectively. In both years, adding a grass cover crop increased predatory arthropods but reduced yield in follow corn crop. Of the arthropods collected, Carabidae and Araneae had greater activity with cover crop biomass increments, whereas Collembola and Acari activity only increased in treatments with little or no cover crop biomass. Insect pest pressure was not significant in any treatment for either year. A cover crop planted in mid- or late-September and terminated at corn planting was identified as the best management strategy to maximize cover crop biomass, increase predator activity, and modify predator-prey dynamics. The results of this study provide growers with a cover crop management strategy to maximize cover crop biomass, beneficial arthropod activity, and potentially minimize insect pest problems; however, corn Zea Mays (L.) grain yield was reduced as cover crop biomass increased.

Twenty years after the arrival of soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in the United States, it remains the most economically important arthropod pest of soybean in the Upper Midwest Region. After years of repeated and sustained insecticidal pressures placed on the aphid, resistance to the pyrethroid class of insecticides has been documented in multiple years over a large geographic area. In this study, the fitness of aphid isolates displaying resistant and susceptible phenotypes to λ-cyhalothrin were compared within several experiments over three soybean-growing seasons. Rates of population increase were evaluated on whole plants in the greenhouse, intrinsic rates of increase were calculated from leaf discs in the laboratory, and aphid size and asymmetry were compared through tibial measurements. No evidence of a fitness cost associated with the resistant phenotype was seen in any of our experiments. In contrast, individual resistant isolates occasionally supported significantly higher fitness values than some susceptible isolates. Additionally, a pooled analysis comparing resistant and susceptible phenotypes across years and isolates revealed that, on average, the resistant phenotype had significantly higher fitness values than the susceptible phenotype in most experiments. The lack of reproductive fitness costs associated with the pyrethroid-resistant phenotype raises concerns for longevity of pyrethroid use in soybean aphid management.

Over the last decade, numerous companies have marketed aqueous ozone sprayers for insect and disease management, but little to no data has been published on their efficacy. Thus, we evaluated the potential of both gaseous and aqueous ozone as a potential preharvest insecticide against the adult life stage of the invasive fruit pest, spotted-wing drosophila, Drosophila suzukii (Matsumura). Gaseous ozone was applied at two dosages, 14,600 and 30,100 ppmv, for varying durations and the respective concentration-time (CT) exposure responses were modeled for sex-specific mortalities recorded at 0, 24, 48, and 72 h following treatment. We found that gaseous ozone primarily caused mortality immediately following exposure, with slight increases 72 h following ozone treatments. The female and male lethal concentration-time (LCT) 50 estimates were significantly different at 0, 24, 48, and 72 h after 30,100 ppmv treatments, where males observed an increased mortality response. However, the LCT 99 estimates confidence intervals (95%) of adult female and male D. suzukii were similar at 0, 24, 48, and 72 h after 14,600 or 30,100 ppmv ozone treatments. In contrast, ozone dissolved in distilled water at 18.52 ppm (mg/L) did not provide any mortality after total immersion of subjects for 30 s. While gaseous ozone may have some utility as a fumigant for D. suzukii in closed vessels where concentrations could be maintained, we did not identify any insecticidal potential for ozone dissolved in aqueous solution when simulating a preharvest treatment under optimal laboratory conditions.

Ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) and Phytophthora root rot (Peronosporales: Peronosporaceae) cause significant damage to the ornamental industry in the United States. In this study, mefenoxam (fungicide), permethrin (insecticide), and charcoal + kaolin were used in different combinations with Phytophthora cinnamomi (Rands: Peronosporales: Peronosporaceae) inoculated and noninoculated plants to optimize the management of ambrosia beetles and Phytophthora root rot. Treatment applications were performed in two trials on 1 (mefenoxam, drench), 18 (P. cinnamomi inoculation), or 19 (permethrin, spray) days before instigating flood stress or 2 d after flood stress (charcoal + kaolin, spray), respectively. Flooding was maintained for 21 d. Ambrosia beetle attacks and plant growth data were recorded. Tree roots were rated at study end for disease severity and root samples were plated on PARPH-V8 medium to determine the percentage of pathogen recovery. In both trials, the combination of mefenoxam + permethrin treatment had reduced disease severity and ambrosia beetle attacks compared to the inoculated controls. Permethrin-treated trees had shorter galleries compared to controls in trial 1 and no gallery formation in trial 2. In both trials, no differences were observed among the treatments in numbers of galleries with eggs and adults, but mefenoxam + charcoal + kaolin had significantly fewer galleries with larvae among the noninoculated trees compared with the respective control in trial 1. Overall, treatments containing combinations of mefenoxam + permethrin had reduced disease severity and ambrosia beetle attacks.

The Caribbean fruit fly, Anastrepha suspensa (Loew) (Diptera: Tephritidae), is a quarantine pest of Citrus spp. and a production pest of guava and other specialty fruits in Florida. Effective monitoring lures and traps are needed for early pest detection and timely initiation of control measures. As part of a continued effort to identify attractive synthetic lures for the Caribbean fruit fly, we conducted field tests in Homestead, Florida to compare the efficacy and longevity of commercial 2- and 3-component cone lures (2C [ammonium acetate and putrescine], 3C [ammonium acetate, putrescine, and trimethylamine]), the current standards used by regulatory agencies, versus the traditional liquid protein bait consisting of hydrolyzed torula yeast and borax as a positive control. Additional lures were also field-aged and periodically brought into the laboratory to quantify residual chemical contents. Traps baited with the torula yeast-borax mixture captured the highest mean number of A. suspensa, and traps baited with the commercial 2C lures captured more flies than the 3C lures. Traps baited with torula yeast-borax also captured the highest number of nontarget Diptera. Captures with all three treatments were significantly biased toward females. Attractiveness of the 2C lure began to drop after 6–8 wk, and the 3C lure after 5–6 wk. Overall, these data suggest that the 2C cone lure is more attractive to A. suspensa than the 3C cone lure under field conditions in south Florida, and that the 2C lures are attractive for up to 8 wk.

Cycloxaprid, 9-((6-chloropyrid-3-yl)methyl)-4-nitro-8-oxa-10,11-dihydroimidazo-[2,3-a]-bicyclo-[3,2,1]-oct-3-ene, is a cis-configuration neonicotinoid insecticide. In the present study, the lethal and sublethal effect of cycloxaprid against Formosan subterranean termites, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), was evaluated and compared with fipronil. Toxicity bioassays showed that cycloxaprid had slightly lower toxicity than fipronil. The minimum cycloxaprid concentration in sand and soil that causes 100% termite mortality was 100 ppm. Similar to fipronil, cycloxaprid significantly reduced wood consumption and tunneling activities of termites. In the tunneling-choice tests, termite tunneling activity measured in both length and area was significantly lower in sand treated with cycloxaprid (10 or 100 ppm) than that in untreated sand. In the aggregation-choice tests, cycloxaprid exhibited inhibition to termite aggregation starting from 100 ppm. In addition, cycloxaprid exhibited significant horizontal transfer effect at 10 ppm. In conclusion, our study showed that cycloxaprid is slightly less toxic than fipronil and more repellent to C. formosanus than fipronil. Future studies are needed to evaluate the effectiveness of cycloxaprid against subterranean termites in the field.

New infestations of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), were discovered in southern California, namely in Rancho Santa Fe and La Mesa (San Diego County) and Highland Park (Los Angeles County) in 2021. We investigated whether these new infestations were related to the previous infestations in La Mesa (2018) and Canyon Lake, Riverside County (2020). We used two mitochondrial genes (COI and COII) and seven polymorphic microsatellite markers to infer the genetic relationship between southern California colonies and their breeding systems. The samples collected from seven localities belonged to five colonies (inter-colony distances ranged from ∼160 m to 185 km, with an average of 97 km). Of these five colonies, two were simple families, and three were extended families. Structure analyses of microsatellite genotypes grouped the termite samples into three distinct genetic clusters, suggesting at least three independent introduction events in southern California.

Fallarmyworm, Spodoptera frugiperda, is one of the most devastating invasive pests in China. Chlorantraniliprole (CH) is currently the main agent for controlling S. frugiperda. Carbaryl (CA) has been widely used as a foliar treatment to control S. frugiperda, although the pest has become highly resistant to it. This study investigates the comparative toxicity and joint effects of CH and CA on S. frugiperda. Time-toxicity results showed that CH had high toxicity to 1st and 3rd instar larvae, whereas CA had very low toxicity to 1st and 3rd instar larvae. The mixtures of CH and CA at different mass ratios showed strong synergistic effects on toxicity, and the mass ratio of 2:1 exhibited the highest toxicity to S. frugiperda. Furthermore, the synergistic toxicity of CH and CA at the 2:1 mass ratio (CH+CA) was also verified in field populations of S. frugiperda. The life-history parameters showed that CH+CA dramatically decreased the survival rate and fecundity of the parent population (F₀) compared with CH treatment at the same concentration. Besides, CH and CH+CA mixture showed induction effect on cytochrome P450s and glutathione-S-transferases (GSTs) activities in S. frugiperda, with cytochrome P450s enzyme responding the fastest. In conclusion, this research found CH+CA provided synergistic effects on the toxicity and the sublethal effect on larvae. The joint effects on the life-history parameters and the detoxifying enzymes in S. frugiperda, may be useful for implementing IPM programs against this Lepidoptera pest.

Graphical Abstract

Diamondback moth, Plutella xylostella is a serious pest of cruciferous vegetables and causes substantial economic loss all over the world. This study was undertaken to decipher the molecular mechanisms involved in the field evolved insecticide resistance in P. xylostella upon exposure to spinosad. To do so, spinosad-resistant and susceptible larval populations were subjected to transcriptome analysis using Illumina paired-end sequencing. De novo assembly was generated from raw reads of both the samples which resulted in the identification of 41,205 unigenes. Functional annotation and digital gene expression analysis were carried out to determine the differentially expressed genes. 1,348 unigenes were found to have a significant differential expression in the resistant population. Several genes involved in insecticide resistance like CYP P450, GSTs, small heat shock protein, and UDP glycosyltransferase were found to be up-regulated while genes related to mitochondrial energy metabolism and cuticular processes were down-regulated. Further, gene mining and phylogenetic analysis of two important gene families namely, CYP and GSTs were performed and the results revealed that these genes could play a major role in the development of field evolved spinosad resistance in P. xylostella by gene duplication and differential gene expression.

Graphical Abstract

The beet armyworm, Spodoptera exigua (Hübna) is a serious agricultural pest that is challenging to control due to resistance to most pesticides, including pyrethroids. This resistance has previously been linked to the knockdown resistance (kdr) mutation (L1014F) of the voltage-gated sodium channel (VGSC) in S. exigua. To better understand the frequencies of the kdr mutation of SeVGSC and identify the evolutionary origins of kdr mutation in S. exigua, seven populations of S. exigua were collected in China, and partial SeVGSC genomic sequences for each individual were acquired. The bioassays showed that the survival rates of seven populations of S. exigua larvae exposed to the discriminating dose of beta-cypermethrin (0.05 mg/ cm²) ranged from 91.66% to 100%, indicating that all seven populations had evolved resistance to beta-cypermethrin. The frequencies of kdr mutation (CTT to TTT) of SeVGSC of field populations ranged China were from 60% to 89.6%. The CTT to CAT substitution at this coding position resulting in the L1014H (kdr-H) mutation was found in only one individual from the QP18 population. Based on the phylogeny of SeVGSC alleles, it appeared that the kdr mutation in S. exigua populations had multiple origins, which has major consequences for pyrethroid effectiveness in the field. Thus, it is recommended to limit the use of pyrethroid and encourage rotation of insecticides with different modes of action for control of S. exigua to alleviate resistance development.

The M14 family metal carboxypeptidase genes play an important role in digestion and pathogenic infections in the gut of insects. However, the roles of these genes in Antheraea pernyi (Guérin-Méneville, 1855) remain to be analyzed. In the present study, we cloned a highly expressed M14 metal carboxypeptidase gene (ApMCP1) found in the gut and discovered that it contained a 1,194 bp open reading frame encoding a 397-amino acid protein with a predicted molecular weight of 45 kDa. Furthermore, 14 members of the M14 family metal carboxypeptidases (ApMCP1–ApMCP14) were identified in the A. pernyi genome, with typical Zn_pept domains and two Zn-anchoring motifs, and were further classified into M14A, M14B, and M14D subfamilies. Expression analysis indicated that ApMCP1 and ApMCP9 were mainly expressed in the gut. Additionally, we observed that ApMCP1 and ApMCP9 displayed opposite expression patterns after starvation, highlighting their functional divergence during digestion. Following natural infection with baculovirus NPV, their expression was significantly upregulated in the gut of A. pernyi. Our results suggest that the M14 family metal carboxypeptidase genes are conservatively digestive enzymes and evolutionarily involved in exogenous pathogenic infections.

The lesser grain borer Rhyzopertha dominica is the major pest of stored paddy rice globally, including inTaiwan. It has strong phototaxis and is good at flying, suitable for developing a light-trapping method to monitor and control it. In the present study, a wavelength of light-emitting diodes (LEDs), i.e., 373 nm, was determined to be the most efficient to trap R. dominica using a dodecagon maze. Accordingly, an LED trap, named the Taiwan Agricultural Research Institute-LED (TARI-LED) trap, was invented, which comprised LEDs of two distinct wavelengths (373 and 408 nm), a wavelength switch, a suction fan, and an insect collector. The trapping efficiency was assessed in a 4-m³ laboratory arena and two paddy rice storehouses. An initial assessment was performed in the laboratory arena and showed that the TARI-LED trap with 373-nm wavelength for R. dominica rapidly increased in the first 30 min, reaching the highest trapping rate (68.5%) after 3 h. In addition, no significant difference was observed between the suction fan turned on or off. The field tests showed that the 373-nm wavelength had the highest effectiveness for trapping R. dominica in the two paddy rice storehouses, and no significant difference was observed in the number of R. dominica trapped by the 373-nm TARI-LED trap or the CDC-UV light trap. In conclusion, our TARI-LED trap 373 nm exhibited high efficiency in trapping R. dominica in paddy rice storehouses. Moreover, a suction fan-free design should benefit long-term and safe use in paddy rice storehouses trapping R. dominica.

Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae) is an insect pest in poultry production systems. This insect has developed resistance to many chemical insecticides. As an alternative to chemicals, entomopathogenic nematodes (EPNs) are one of the most commonly used agents against several pest arthropods. The pathogenicity of the EPN Steinernema carpocapsae Weiser on four field strains of lesser mealworm, A. diaperinus, from Turkey was studied. In the experiments, larvae of A. diaperinus were found to be more sensitive than adults to S. carpocapsae infection. In terms of LC₅₀ values in both larval and adult insects, Balikesir strain was found to be the most susceptible, Manisa strain the most resistant. The calculated LC₅₀ values for adults were 85.9, 205.6, 135.4, and 418.8 IJs/ml, and for larvae 31.2, 39.8, 34.8, and 70.9 IJs/ml for the Balikesir, Canakkale, İzmir, and Manisa strains, respectively. This is the first report about the pathogenicity of EPNs against larvae and adults of lesser mealworm A. diaperinus strains from Turkey. We conclude that S. carpocapsae can be used as a control agent for lesser mealworms.

Spotted wing drosophila, Drosophila suzukii (Matsumura), is an important invasive insect pest in the United States. Spotted wing drosophila females have serrated ovipositor that enables them to deposit eggs inside healthy, ripening softskinned fruits. In many berry and fruit crops, spotted wing drosophila is primarily controlled using synthetic insecticides in the organophosphate, pyrethroid, and spinosyn groups. However, alternative, reduced-risk insecticides with short residuals are necessary to minimize the possibilities of insecticide resistance and address other negative effects of synthetic insecticides. Neem-based products as alternative plant-based insecticides have antifeedant, repellent, antiovipository, and molting interference effects on insects and have been shown to affect the oviposition activities of some tephritid flies. We conducted laboratory studies to evaluate the oviposition deterrent activities of selected neem-based insecticides that contain either azadirachtin, or CHENO, or a combination of both, on spotted wing drosophila using sweet cherry in California. The results of the study showed that some of the neem oil products could reduce the degree of spotted wing drosophila oviposition by half compared with the control.