Potential Alternatives to Spinosad as the Killing Agent Mixed With Two Attractant Products in Attract-and-Kill Formulations Used to Manage the Spotted-Wing Drosophila, Drosophila suzukii (Diptera: Drosophilidae)

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a key pest of many berry and fruit crops worldwide. The primary method of controlling this pest is the application of insecticides. Attract-and-kill is a management tactic that may reduce the number of insecticide applications needed to manage D. suzukii. ACTTRA SWD OR1 and ACTTRA SWD TD, developed by ISCA Technologies Inc., combine D. suzukii attractants with a gel matrix. Growers add an insecticide as a killing agent. The only USDA National Organic Program approved organic insecticide that has been shown to be effective as a killing agent is spinosad. This study aimed to determine the efficacy of other USDA National Organic Program approved organic insecticides, including Grandevo 30 WDG (Chromobacterium subtsugae strain PRAA4-1 30%), MBI-203 SC2 (C. subtsugae strain PRAA4-1 98%), Venerate XC (Burkholderia spp. Strain A396 94.45%), MBI-306 SC1 (B. rinojensis Strain A396 94.45%), Azera (azadirachtin 1.2% + pyrethrins 1.4%), and PyGanic (pyrethrins 1.4%), when used as the killing agent with the two ACTTRA SWD products. Lab and cage bioassays were conducted. Entrust (spinosad 22.5%) and PyGanic were the only compounds that showed some efficacy when used with ACTTRA SWD OR1 and ACTTRA SWD TD.

Yeast mediates the interspecific interaction between introduced Bactrocera dorsalis and indigenous Bactrocera minax

BACKGROUND

Host plant-microbe associations mediate interspecific interactions amongst herbivorous insects. However, this theory has rarely been ecologically verified in tephritid fruit flies. Research on this subject can not only help predict tephritid species invasion and occurrence patterns, but also develop potential novel lures for the control of the tephritid fruit fly pests. Recently, we observed mixed infestation of Bactrocera minax and Bactrocera dorsalis larvae in citrus orchards, which prompted us to explore the underlying mechanism.

RESULTS

Following oviposition by B. minax, the yeast Pichia kluyveri translocated to and proliferated inside the citrus fruit. The level of d-limonene released from citrus fruits containing P. kluyveri was 27 times higher than that released from healthy fruits. Mature B. dorsalis females were attracted to d-limonene and oviposited into fruits previously infested by B. minax. Furthermore, the interspecific interaction between B. dorsalis and B. minax within the same fruit significantly decreased the number of surviving larvae and pupal weight in B. dorsalis, but its effect on B. minax was weaker.

CONCLUSION

In the studied interspecific interaction, B. minax occupies the dominant position, implying ecological significance for this species in terms of consolidating its own niche and inhibiting the invasion of exotic species. To our best knowledge, this is the first report from both ecological and physiological perspectives on a symbiotic yeast mediating the interaction between B. minax and B. dorsalis through altering fruit volatiles. © 2022 Society of Chemical Industry.

Lethal and sublethal effects of chlorantraniliprole on the migratory moths Agrotis ipsilon and A. segetum: New perspectives for pest management strategies

BACKGROUND

Agrotis ipsilon and A. segetum are major migratory pests of many crops in China, and frequent regional outbreaks cause severe yield losses. Use of food attractants is one of the most promising control methods against adult lepidoptera, notably through the attract-and-kill strategy. Chlorantraniliprole's acute toxicity and sublethal effects on both moths were evaluated.

RESULTS

Chlorantraniliprole showed high activity against both adults of both species, with LC₂₀ and LC₅₀ values of 0.08 and 0.21 mg L^-1 (A. ipsilon), and 0.14 and 0.51 mg L^-1 (A. segetum). The fecundity, effective oviposition rate, and egg hatching rate of both species in dual-sex exposure treatments were all significantly reduced compared with the control, and the population growth coefficients in the LC₅₀ ♀ × LC₅₀ ♂ treatments were only 0.32% (A. ipsilon) and 3.35% (A. segetum) that of the control. Furthermore, the flight distance was significantly suppressed from 6.67 km (control) to 0.01 km (LC₅₀ ) for A. ipsilon, and from 7.39 km (control) to 0.78 km (LC₅₀ ) for A. segetum. The proportions of robust- and medium-flight individuals of A. ipsilon and A. segetum in exposure treatments were greatly reduced.

CONCLUSIONS

Low lethal concentration exposures to chlorantraniliprole can drastically reduce the reproduction and flight performance of A. ipsilon and A. segetum, while inhibiting the production of offspring, suggesting chlorantraniliprole would be an excellent compound for use in combination with food attractants. Chlorantraniliprole has good potential for management of the two long-range migratory pests tested using an attract-and-kill strategy. © 2022 Society of Chemical Industry.

Factors Influencing the Efficacy of Novel Attract-and-Kill (ACTTRA SWD) Formulations Against Drosophila suzukii

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.

Bisexual Attract-and-Kill: A Novel Component of Resistance Management for Transgenic Cotton in Australia

In Australia, destruction of overwintering pupae of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) has been a key component of mandatory resistance management schemes to constrain development of resistance to Bt toxins in transgenic cotton. This has been accomplished by tillage ('pupae busting'), but it is expensive and can interfere with farming operations. Bisexual attract-and-kill technology based on plant volatile formulations offers a potential alternative in some circumstances. We discuss strategies for using such products and describe two trials in which three applications of an attract-and-kill formulation substantially reduced the numbers of Helicoverpa spp. moths and the numbers of potentially overwintering eggs they laid. One trial tested a curative strategy in which the last generation of moths emerging from transgenic cotton was targeted. The other tested a preventive strategy which aimed to reduce the numbers of eggs in the last generation. The preventive strategy reduced egg numbers by about 90% and is now included as an optional alternative to pupae busting in resistance management strategies for Australian cotton. It is limited to fields which have not been defoliated prior to 31 March and was developed to be used primarily in southern New South Wales. In the 2020-2021 cotton season, it was adopted on approximately 60% of the eligible cotton area. We describe the process whereby the strategy was developed in collaboration with the transgenic technology provider, supported by the cotton industry, and approved by the regulatory authority.

Improved Captures of the Invasive Brown Marmorated Stink Bug, Halyomorpha halys, Using a Novel Multimodal Trap

Simple Summary

Pest monitoring using traps is a key component of integrated pest management. For several insects, trapping is achieved using visual or olfactory stimuli. Although the combination of both is supposed to provide higher efficacy, this has often been overlooked in trap design. Through laboratory bioassays and field experiments we evaluated the use of UV-A and visible light in combination with olfactory stimuli to improve trapping of the invasive brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae). Our results may be useful for the improvement of monitoring strategies for early pest detection. Additionally, the higher efficacy of the multimodal traps would allow their use in attract-and-kill or push–pull strategies within integrated pest management.

Abstract

Capture strategies for the brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae), are challenging. Here we developed and evaluated a multimodal trap which combines visual and olfactory stimuli. Visual stimuli consisted of LEDs emitting UV-A and visible light. Olfactory stimuli were comprised of the synthetic aggregation pheromone and odours from trapped H. halys individuals. Stink bug attraction at different wavelengths was evaluated in laboratory two-choice bioassays, and different prototypes of the trap were tested in 2021 in natural, agricultural, and urban settings. Traps with a combination of UV-A and blue or green visible wavelengths provided higher H. halys attraction (up to ~8-fold) compared to traditional sticky or small pyramidal traps. The concurrent presence of synthetic pheromone and LED had a synergistic effect on H. halys positive phototaxis. Further development and implementation of the multimodal trap is discussed for prospective use in attract-and-kill or push–pull strategies.

Compatibility of a Beta-cyfluthrin-Based 'Attract-and-Kill' Device with Tamarixia radiata (Hymenoptera: Eulophidae) for Suppression of Diaphorina citri (Hemiptera: Liviidae) on Residential Citrus

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a serious threat to the U.S. citrus industry because it spreads huanglongbing (HLB), a bacterial and incurable citrus disease. The nymphal parasitoid, Tamarixia radiata Waterston (Hymenoptera: Eulophidae), has been extensively released for biological control of D. citri in South Texas since 2010 but provides insufficient control. An 'attract-and-kill' (AK) device was evaluated for its compatibility with T. radiata for suppression of D. citri on dooryard citrus. The AK device is visually attractive to D. citri adults because it is the same color as young citrus flush and kills individuals on contact with the toxicant beta-cyfluthrin. This study evaluated 1) lethality of AK devices to T. radiata adults under lab conditions; 2) efficacy of AK devices for year-round psyllid suppression on individual dooryard lemon trees; 3) discovery and parasitism of D. citri colonies by T. radiata on lemon trees with or without AK devices. Contact with AK devices for 5 s or more was lethal to adult parasitoids. Deployment of 20 AK devices per tree provided significant year-round suppression of D. citri on infested lemon trees and reduced mean attack intensity (cumulative psyllid-days) of adults by 66% and nymphs by 82%. Discovery and parasitism rates of D. citri colonies by T. radiata were similar on control trees and trees protected by AK devices. An AK device that targets adult psyllids could be used to effectively complement biological control of D. citri by T. radiata in residential landscapes.

Bioactivity of Carlina acaulis Essential Oil and Its Main Component towards the Olive Fruit Fly, Bactrocera oleae: Ingestion Toxicity, Electrophysiological and Behavioral Insights

Among botanical insecticides based on essential oils (EOs) or their main components, Carlina acaulis EO and the aromatic polyacetylene carlina oxide, constituting more than 90% of its EO, were recently proven to be effective against the larvae and adults of some insect vectors and pests. In this study, the toxicity of C. acaulis EO and carlina oxide were tested on Bactrocera oleae adults using a protein bait formulation. The LC₅₀ values of the C. acaulis EO and carlina oxide were 706 ppm and 1052 ppm, respectively. Electroantennographic (EAG) tests on B. oleae adults showed that both carlina EO and oxide elicited EAG dose-dependent responses in male and female antennae. The responses to the EO were significantly higher than those to carlina oxide, indicating that other compounds, despite their lower concentrations, can play a relevant role. Moreover, Y-tube assays carried out to assess the potential attractiveness or repellency of carlina oxide LC₉₀ to B. oleae adults showed that it was unattractive to both males and females of B. oleae, and the time spent by both sexes in either the control or the treatment arm did not differ significantly. Overall, this study points out the potential use of C. acaulis EO and carlina oxide for the development of green and effective "lure-and-kill" tools.

A Systematic Review of the Behavioral Responses by Stored-Product Arthropods to Individual or Blends of Microbially Produced Volatile Cues

Microbes are ubiquitous and play important ecological roles in a variety of habitats. While research has been largely focused on arthropods and microbes separately in the post-harvest supply chain, less attention has been paid to their interactions with each other. Up to this point, there has been no attempt to systematically describe the patterns of behavioral responses by stored-product insects to microbially produced volatile organic compounds (MVOCs). Thus, our aims were to evaluate whether stored-product arthropods were primarily and significantly attracted, repelled, or had a net neutral effect (e.g., unaffected or mixed) by MVOCs presented as (1) complex headspace blends or (2) single constituents and known mixtures. In total, we found 43 articles that contained 384 sets of tests with different combinations of methodology and/or qualitative findings, describing the behavioral responses of 24 stored-product arthropod species from two classes, four orders, and 14 families to 58 individual microbial compounds and the complex headspace blends from at least 78 microbial taxa. A total of five and four stored-product arthropod species were significantly attracted and repelled by MVOCs across odor sources, respectively, while 13 were unaffected or exhibited mixed effects. We summarize the biases in the literature, including that the majority of tests have occurred in the laboratory with a limited subset of methodology and has largely only assessed the preference of adult arthropods. Finally, we identify foundational hypotheses for the roles that MVOCs play for stored-product arthropods as well as gaps in research and future directions, while highlighting that the behavioral responses to MVOCs are complex, context-, and taxon-dependent, which warrants further investigation.

Brown marmorated stink bug overwintering aggregations are not regulated through vibrational signals during autumn dispersal

The brown marmorated stink bug, Halyomorpha halys (Heteroptera: Pentatomidae), is regarded as one of the world's most pernicious invasive pest species, as it feeds on a wide range of economically important crops. During the autumn dispersal period, H. halys ultimately moves to potential overwintering sites, such as human-made structures or trees where it will alight and seek out a final overwintering location, often aggregating with other adults. The cues used during this process are unknown, but may involve vibrational signals. We evaluated whether vibrational signals regulate cluster aggregation in H. halys in overwintering site selection. We collected acoustic data for six weeks during the autumn dispersal period and used it to quantify movement and detect vibrational communication of individuals colonizing overwintering shelters. Both movement and vibrational signal production increased after the second week, reaching their maxima in week four, before decaying again. We found that only males produced vibrations in this context, yet there was no correlation between movement and vibrational signals, which was confirmed through playback experiments. The cues regulating the formation of aggregations remain largely unknown, but vibrations may indicate group size.

Tunnel entries and a killing agent uncover the importance of fly retention in Drosophila suzukii traps

BACKGROUND

Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a pest of stone and small fruits causing considerable economic losses. Current management strategies rely primarily on calendar-based spraying, owing to the poor relationship between monitoring data and damage levels, and the lack of success of mass-trapping tools. The aim of this study was to evaluate different trap models for SWD, with an emphasis on their fly-retention capacity. To this end, we examined and quantified the added value of two fly-retaining trap features; tunnel entries to impede escape and an insecticide-coated inner surface as a killing agent.

RESULTS

An insecticide-coated inner surface resulted in significantly higher trap retention after 24 h in the laboratory (4.9- to 7.4-fold greater, depending on trap type) compared to a noncoated trap. Trapping efficacy was significantly improved in field trials by such a killing agent in the trap (1.2- to 4.5-fold greater). Tunnel entries significantly improved trap retention in the laboratory and field (by 1.5-fold).

CONCLUSION

The outcomes of this study clearly reveal the substantial impact of the fly-retention capacity of SWD traps on their overall capture performances. It was demonstrated for the first time that an insecticide-coated inner surface as a killing agent significantly improves trap efficacy for SWD. This finding can readily be implemented in any trap model to improve monitoring and mass trapping of SWD. Also tunnel entries were shown to have a significant influence on the fly retention and, hence, substantially enhance trapping efficacy.

Integration of Entomopathogenic Fungi into IPM Programs: Studies Involving Weevils (Coleoptera: Curculionoidea) Affecting Horticultural Crops

Weevils are significant pests of horticultural crops and are largely managed with insecticides. In response to concerns about negative impacts of synthetic insecticides on humans and the environment, entomopathogenic fungi (EPF) have been developed as an alternative method of control, and as such appear to be "ready-made" components of integrated pest management (IPM) programs. As the success of pest control requires a thorough knowledge of the biology of the pests, this review summarises our current knowledge of weevil biology on nut trees, fruit crops, plant storage roots, and palm trees. In addition, three groups of life cycles are defined based on weevil developmental habitats, and together with information from studies of EPF activity on these groups, we discuss the tactics for integrating EPF into IPM programs. Finally, we highlight the gaps in the research required to optimise the performance of EPF and provide recommendations for the improvement of EPF efficacy for the management of key weevils of horticultural crops.

Comparison and Refinement of Integrated Pest Management Tactics for Halyomorpha halys (Hemiptera: Pentatomidae) Management in Apple Orchards

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) has been managed primarily with broad-spectrum insecticides in orchard systems. Recently, IPM techniques have been developed specifically for managing H. halys in apple orchards to reduce insecticide inputs and take advantage of its perimeter-driven behavior. In 2015 and 2016, we compared these IPM tactics to one another and an untreated control to measure differences in overall crop protection and insecticide inputs. Tactics included trap-based threshold-triggered spray applications, perimeter-based attract-and-kill (AK) trees treated every 7- and 14-d, and perimeter spray applications applied every 7- and 14-d. All plots were monitored with baited black pyramid traps deployed in plot interiors. In both years, mean number of H. halys captured in untreated control plot traps was significantly greater than plots managed using IPM tactics. In 2015, significantly more insecticide applications were made in 7- and 14-d perimeter and AK plots compared with trap-based threshold plots. There was no significant difference in the percentage of injured fruit in plot interiors among IPM tactics; all were significantly lower than the control. In 2016, significantly more insecticide applications were made in 7-d perimeter spray and AK plots compared with all other treatments. Significantly less injury was detected in plot interiors for 7- and 14-d perimeter and trap-based threshold plots compared with the control and 7- and 14-d AK plots. Although all IPM tactics reduced H. halys injury in apples using a trap-based treatment threshold required fewer insecticide inputs and only during brief periods of the season, while all others required season-long maintenance.

Acetogenin-Based Formulated Bioinsecticides on Anastrepha fraterculus: Toxicity and Potential Use in Insecticidal Toxic Baits

The present study evaluated the lethal toxicity and oviposition deterrence of ethanolic extracts of Annona mucosa Jacq., Annona muricata L., and Annona sylvatica A. St.-Hil on Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) compared with those of a limonoid-based bioinsecticide (Azamax™ 1.2 EC-azadiractin +3-tigloyl-azadiractol) and a synthetic spinosyn-based insecticide (Delegate™ 250 WG-spinetoram). In addition, the efficacy of the selected toxic bait formulations was evaluated by mixing them with food attractants (Anamed™, 3% Biofruit and 7% sugarcane molasses). In the topical application and ingestion bioassays (2000 mg L^-1), the aqueous emulsion of the A. mucosa extract caused greater than 80% mortality of A. fraterculus adults in a similar manner to the spinosyn-based synthetic insecticide. Concentration-response curves were performed for the most promising treatments and showed an activity level dependent on the mode of contamination, exposure time, and applied concentration. In bioassays with and without choice, the A. mucosa (77%), A. muricata (51%), A. sylvatica (60%), Azamax™ (74%), and Delegate™ 250 WG (100%) significantly reduced the number of punctures and galleries in grape berries. In combination with the food attractants Anamed™, 3% Biofruit, and 7% sugarcane molasses, the emulsion of the A. mucosa extract had a residual effect similar to that of the spinetoram insecticide, with a mortality rate of over 80% of A. fraterculus adults up to 14 days after application (DAA) in the absence of rain. Thus, acetogenin-rich formulations, especially from A. mucosa seeds, are useful alternatives for the integrated management of A. fraterculus in agricultural orchards.

Development and Field Validation of a Beta-cyfluthrin-Based 'Attract-and-Kill' Device for Suppression of Asian Citrus Psyllid (Hemiptera: Liviidae) on Residential Citrus

An 'attract-and-kill' (AK) device was evaluated for suppression of adult Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), on residential citrus. The AK device, made from weather-resistant plasticized PVC, lured D. citri adults by simulating the color of citrus flush and killed them with beta-cyfluthrin. This study evaluated: 1) lethality of AK devices weathered up to 8 wk on residential citrus; 2) survival of psyllids caged with potted plants and AK devices; 3) psyllid suppression achieved by AK devices on individual dooryard trees. AK devices weathered for up to 8 wk remained lethal to psyllids. Greenhouse trials evaluated survival of adult psyllids caged for 4 d with orange jasmine plants that were: 1) treated with an (beta-cyfluthrin-infused) AK device; 2) treated with a blank (no insecticide) AK device; or 3) 'untreated' with no AK device. After 4 d, psyllid survival was on average 95% lower among adults exposed to plants with AK devices than adults exposed to untreated plants or plants with blank AK devices. Less than half of the adults exposed to plants with AK devices were alive after 1 d and nearly all were dead after 4 d. Deployment of 20 AK devices per tree provided significant psyllid suppression on infested lemon trees from winter to summer and reduced mean reproduction (cumulative eggs) by 91% and mean attack intensity (cumulative psyllid-days) of adults by 59% and nymphs by 53%. AK devices could be an effective control option for D. citri in urban areas.

Avoiding Unwanted Vicinity Effects With Attract-and-Kill Tactics for Harlequin Bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae)

In the development of an attract-and-kill approach for the management of harlequin bug (HB), Murgantia histrionica (Hahn), we evaluated attraction and retention of HB by pheromone-baited traps in the field. In release-recapture and on-farm experiments, traps with collard plants with lures-containing HB aggregation pheromone (murgantiol = 10,11-epoxy-1-bisabolen-3-ol) arrested and retained more HB than traps with either plant or lure. In order to avoid unwanted vicinity effects (increased feeding injury to neighboring crop plants due to halo or spillover effects), we also investigated two methods of retaining HB that were attracted to traps: a systemic toxicant (neonicotinoid applied to the trap plant as a drench) and a contact toxicant (long-lasting insecticidal netting [LLIN] with incorporated pyrethroid). More HB adults and more HB-feeding injury were observed on collard plants in the vicinity of lures compared with those neighboring lures in combination with a systemic toxicant. This difference indicates that improvements to trap retention acted to mitigate spillover effects, thereby avoiding unwanted vicinity effects. We also conducted laboratory assays in order to estimate the length of exposure to LLIN necessary to knock down HB adults and nymphs, calculating a knockdown time (KDT50) of 78.3, 2.6, and 2.1 s for females, males, and nymphs, respectively.

Development of an attract-and-kill co-formulation containing Saccharomyces cerevisiae and neem extract attractive towards wireworms

BACKGROUND

Wireworms (Coleoptera: Elateridae) are major insect pests of worldwide relevance. Owing to the progressive phasing-out of chemical insecticides, there is great demand for innovative control options. This study reports on the development of an attract-and-kill co-formulation based on Ca-alginate beads, which release CO₂ and contain neem extract as a bioinsecticidal compound. The objectives of this study were to discover: (1) whether neem extract can be immobilized efficiently, (2) whether CO₂ -releasing Saccharomyces cerevisiae and neem extract are suitable for co-encapsulation, and (3) whether co-encapsulated neem extract affects the attractiveness of CO₂ -releasing beads towards wireworms.

RESULTS

Neem extract was co-encapsulated together with S. cerevisiae, starch and amyloglucosidase with a high encapsulation efficiency of 98.6% (based on measurement of azadirachtin A as the main active ingredient). Even at enhanced concentrations, neem extract allowed growth of S. cerevisiae, and beads containing neem extract exhibited CO₂ -emission comparable with beads without neem extract. When applied to the soil, the beads established a CO₂ gradient of >15 cm. The co-formulation containing neem extract showed no repellent effects and was attractive for wireworms within the first 24 h after exposure.

CONCLUSION

Co-encapsulation of S. cerevisiae and neem extract is a promising approach for the development of attract-and-kill formulations for the control of wireworms. This study offers new options for the application of neem extracts in soil. © 2017 Society of Chemical Industry.

Advances in Attract-and-Kill for Agricultural Pests: Beyond Pheromones

Attract-and-kill has considerable potential as a tactic in integrated management of pests of agricultural crops, but the use of sex pheromones as attractants is limited by male multiple mating and immigration of mated females into treated areas. Attractants for both sexes, and particularly females, would minimize these difficulties. Volatile compounds derived from plants or fermentation of plant products can attract females and have been used in traps for monitoring and control, and in sprayable attract-and-kill formulations or bait stations. Recent advances in fundamental understanding of insect responses to plant volatiles should contribute to the development of products that can help manage a wide range of pests with few impacts on nontarget organisms, but theory must be tempered with pragmatism in the selection of volatiles and toxicants and in defining their roles in formulations. Market requirements and regulatory factors must be considered in parallel with scientific constraints if successful products are to be developed.

Novel nanoscale pheromone dispenser for more accurate evaluation of Grapholita molesta (Lepidoptera: Tortricidae) attract-and-kill strategies in the laboratory

BACKGROUND

Nanotechnology has recently allowed the production of formulations for controlled release of active ingredients. In the present study, the electrospinning technique was used to produce nanoscale dispensers for attract-and-kill strategies. Non-woven nanofibres containing insecticide (cypermethrin) and (E)-8,(Z)-8-dodecenyl acetate and (Z)-8-dodecanol (0.87 mg L^-1 ), the main components of Grapholita molesta (Lepidoptera: Tortricidae) (Busck) pheromone, were evaluated in laboratory experiments. Male electroantennographic (EAG) responses and mortality (tarsal-contact and attract-and-kill behavioural cages) bioassays were performed for nanofibres (with and without insecticide) exposed for different periods (21, 42, 63 and 84 days) in controlled and non-exposed conditions.

RESULTS

There were no significant differences in G. molesta male EAG responses based on the time of exposure within treatments. Nanofibres with pheromone only and with pheromone plus insecticide elicited equal EAG responses. Mortality in tarsal-contact bioassays was greater than 87% after exposure for 84 days. In the attract-and-kill bioassays, mortality ranged from 28.4 to 56.6%, although no difference was observed on insect mortalities over time (24, 48 and 72 h).

CONCLUSION

Incorporation of cypermethrin in nanofibres did not interfere with G. molesta attractiveness. Both aspects of the strategy, the attractant and killing effects, were recorded using innovative nanofibres, and long-term effects suggest a controlled release of pheromone and insecticide. © 2017 Society of Chemical Industry.

Development of an Attract-and-Kill Strategy for Drosophila suzukii (Diptera: Drosophilidae): Evaluation of Attracticidal Spheres Under Laboratory and Field Conditions

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive, polyphagous fruit fly that attacks soft-skinned fruits. Originally from Asia, D. suzukii has successfully invaded the United States and the European and South American countries. At present, calendar-based insecticide applications are used to combat D. suzukii. Here, we evaluate a behaviorally based attract-and-kill management technique using attracticidal spheres to reduce D. suzukii infestations in raspberries. In laboratory bioassays aimed at identifying effective toxicants, attracticidal spheres containing dinotefuran at 1.0% a.i. killed 100% of D. suzukii within 5 min. Spinetoram, spinosad, permethrin, lambda-cyhalothrin (CS) and lambda-cyhalothrin (WG), all at 1.0% a.i., killed 100% of D. suzukii within 24 h. In field trials, statistically equivalent infestation rates were recorded in raspberry plots protected by attracticidal spheres containing 1.0% a.i. spinetoram compared with standard weekly insecticide applications. In field trials using 1.0% a.i. dinotefuran, attracticidal spheres decreased D. suzukii infestations compared with control plots, but insecticide applications were more effective at reducing D. suzukii infestations, although differences in harvesting practices likely affected fly population densities and infestation rates in both years. Attracticidal spheres effectively attract and kill D. suzukii and reduce infestations rates under field conditions, indicating that this behavioral strategy holds promise in D. suzukii management.

The consequences of sublethal exposure to insecticide on the survivorship and mobility of Halyomorpha halys (Hemiptera: Pentatomidae)

BACKGROUND

The direct lethal effects of conventional and organic insecticides have been investigated thoroughly for all life stages of Halyomorpha halys. However, the sublethal effects of insecticides on the behavior of H. halys have not been well documented. Our aims were to evaluate the impact of a brief 5 min exposure to residues of bifenthrin, dinotefuran, methomyl, thiamethoxam and thiamethoxam + λ-cyhalothrin on survivorship, horizontal and vertical movement, and flight capacity of adult H. halys under laboratory conditions.

RESULTS

Over half of the insecticide-exposed adults were classified as affected, moribund or dead after the 5 min exposure, compared with only 6% of the adults in the water-only control. We found that the horizontal movement, vertical climbing and flight capacity of adults exposed to insecticides were decreased by 20-60% overall relative to the water-only control. The most lethal insecticide was bifenthrin.

CONCLUSION

Many insecticide-exposed H. halys adults retained significant mobility and flight capacity, with flight most pronounced immediately after exposure. These results suggest that brief exposure periods to efficacious insecticides will result in high dispersal and low mortality. Therefore, management strategies that enhance the retention of H. halys on insecticide-coated surfaces should be considered to ensure that adults are exposed to a lethal dose of insecticide. © 2016 Society of Chemical Industry.

Development of a CO2 -releasing coformulation based on starch, Saccharomyces cerevisiae and Beauveria bassiana attractive towards western corn rootworm larvae

BACKGROUND

CO₂ is known as an attractant for many soil-dwelling pests. To implement an attract-and-kill strategy for soil pest control, CO₂ -emitting formulations need to be developed. The aim of the present work was to develop a slow-release bead system in order to bridge the gap between application and hatching of western corn rootworm larvae.

RESULTS

We compared different Ca-alginate beads containing Saccharomyces cerevisiae for their potential to release CO₂ over a period of several weeks. The addition of starch improved CO₂ release, resulting in significantly higher CO₂ concentrations in soil for at least 4 weeks. The missing amylase activity was compensated for either by microorganisms present in the soil or by coencapsulation of Beauveria bassiana. Formulations containing S. cerevisiae, starch and B. bassiana were attractive for western corn rootworm larvae within the first 4 h following exposure; however, when considering the whole testing period, the maize root systems remained more attractive for the larvae.

CONCLUSION

Coencapsulation of S. cerevisiae, starch and B. bassiana is a promising approach for the development of attractive formulations for soil applications. For biological control strategies, the attractiveness needs to be increased by phagostimuli to extend contact between larvae and the entomopathogenic fungus growing out of these formulations. © 2016 Society of Chemical Industry.

An attempt to control Cameraria ohridella using an attract-and-kill technique

This study estimates the efficacy of an attract-and-kill (A&K) technique to control the horse chestnut leaf miner, Cameraria ohridella Deschka and Dimic (Lepidoptera, Gracillariidae), an invasive insect pest of the horse chestnut, Aesculus hippocastanum L. (Hippocastanaceae). The A&K formulation was dispensed as 50 μl droplets of paste-like matrix, containing C. ohridella sex pheromone, (8E,10Z)-tetradeca-8,10-dienal (85% + pure; 0.16% w/w) and a fast acting contact toxicant, pyrocides (94% pure; 6% w/w), applied directly to the bark of the trees. It was tested in 2003 at rates of 30 and 45 droplets/tree at the Ostrobramska site and at rates of 30, 60 and 90 droplets/tree at the Woloska site in Warsaw, Poland, for the first insect generation. A set of untreated plots (0 droplets/tree) was established at each site as well. The treatment efficacy was estimated using two indices: (1) moth catches in pheromone traps and (2) the number of mines per leaf. Trap catches were significantly higher in the untreated plots than in the treated plots regardless of the application rate in all sites. However, there were no significant differences in leaf damage amongst all plots on each site. At the "Lazienki Krolewskie" park the attractiveness of two types of pheromone sources were compared: traps were baited with rubber septum lures or with A&K droplets. The catches of C. ohridella in traps baited with lures were lower than captures in A&K droplet-baited traps, but the difference was not significant. Possible reasons for the low efficacy of the A&K method in management of C. ohridella and reducing leaf damage are discussed.

Comparison of rain-fast bait stations versus foliar bait sprays for control of oriental fruit fly, Bactrocera dorsalis, in papaya orchards in Hawaii

Bait stations represent an environmentally friendly attract-and-kill approach to fruit fly population suppression. Recently a novel, visually attractive, rain-fast bait station was developed in Hawaii for potential use against multiple species of pestiferous fruit flies. Here, we compared the efficacy of GF-120 NF Naturalyte Fruit Fly Bait applied either as foliar sprays or onto bait stations in reducing female oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), population density and level of fruit infestation in commercial papaya orchards in Hawaii. Trapping and infestation data were used as indicators of the effectiveness of the two bait application methods. For the first 10 weeks of the study, captures of female B. dorsalis in monitoring traps were significantly greater in control plots than in plots treated with foliar sprays or bait stations. Six weeks after the first bait spray, incidence of infestation (i.e. number of fruit with one or more B. dorsalis larvae) of quarter to half-ripe papaya fruit was reduced by 71.4% and 63.1% for plots with bait stations and foliar sprays, respectively, as compared to control plots. Twelve weeks after first spray, incidence of infestation was reduced by only 54.5% and 45.4% for plots with bait stations and foliar sprays, respectively, as compared to control plots. About 42% less GF-120 was used in orchard plots with bait stations compared to those subject to foliar sprays. The impact of field sanitation on the outcome is also discussed. The results indicate that bait stations can provide a simple, efficient, and economical method of applying insecticidal baits to control fruit flies and a safer alternative to foliar sprays.