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The occurrence and increased dispersion of plant viruses and insect vectors are serious global threat to the production of agricultural crops. Facing novel pathogenic plant viruses, the ability to accurately identify plant virus species, and understand the interaction between plant viruses, host plants and their insect vectors would provide an important basis for formulating effective plant virus control measures. In this study, we explored the transmission mechanism, pathogenic symptoms, host range and the interactions between virus and aphid vectors of a novel polerovirus from Nicotiana tabacum, named Tobacco yellow virus (TYV). The results indicate that TYV can be transmitted by Myzus persicae in a persistent manner, and cause yellowing and shrinking of tobacco leaves. TYV can successfully infect a total of 9 plant species belonging to 3 families. The effect of TYV-infected tobacco plants on M. persicae behavior and life characteristics was found to be stage-dependent. TYV can directly and indirectly manipulate the performance and life history traits of M. persicae vectors to promote their own transmission. These results provide a certain theoretical basis for the possibility of control strategies of the virus, and the in-depth exploration of the interaction among plant virus, vector aphid and host plants. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation, an environmental stressor, is crucial for the survival and adaptation of organisms. Myzus persicae, a global pest, is exposed to sunlight year‐round, making it unable to avoid UV rays in its environment. MicroRNAs (miRNAs) are important posttranscriptional regulators of gene expression and mediate various biological processes. However, the role of miRNA in aphids in response to UV‐B stress is unclear. In this study, Mpp53 expression level significantly increased with an increase in the duration of UV‐B radiation, peaking at 2 h; knockdown of Mpp53 decreased the survival rate of aphids under UV‐B stress, suggesting that Mpp53 is involved in aphid responses to UV‐B. Here, we first predicted 8 miRNAs targeting Mpp53, and then screened for miRNAs related to UV‐B resistance in aphids; of these, 5 miRNAs (miR‐305‐5p, novel_50, novel_80, novel_166, and novel_61) were found to target Mpp53. Luciferase reporter assays demonstrated that novel_61 binds to the noncoding region of Mpp53 and downregulates its expression. Overexpression of novel_61 in aphids decreased Mpp53 expression and caused significant mortality under UV‐B irradiation. Furthermore, the aphids exhibited lower reproductive capacity, lower body weight, and shorter body length and width. This is the first study to systematically screen and identify miRNA related to aphid responses to UV‐B stress and deepens our understanding of the molecular mechanism of insect responses to environmental stress, which may eventually aid in developing better control strategies. [ABSTRACT FROM AUTHOR]

Neonicotinoid resistance is increasingly prevalent in the agricultural pest Myzus persicae. Lipids play a critical role in insect defense systems, but their contribution to insect neonicotinoid resistance is disregarded. We conducted metabolomics and transcriptomics studies on M. persicae thiacloprid-resistant (THG-R) and -susceptible (FFJ-S) populations. A total of 149 lipid metabolites were identified, with 90 upregulated and 59 downregulated in THG-R compared to in FFJ-S. Metabolites in the arachidonic acid (AA) pathway substantially varied between THG-R and FFJ-S. For example, arachidonic acid, (±)11-HETE, and prostaglandin B1 were significantly upregulated, while prostaglandin A1, tetranor-PGDM, 8,15-diHETE, and (±)11(12)-EET were significantly decreased in THG-R. Transcriptomics profiles and qPCR indicated that lipid metabolic enzymes, including fatty acid synthase (FAS), the elongase of very-long-chain fatty acids (ELO), fatty acid desaturase (FAD), and phospholipase (PL) genes, were not overexpressed in THG-R. Among the twelve thioesterase genes, only MpTHEM6a was significantly upregulated in THG-R. Knocking down the expression of MpTHEM6a in THG-R significantly increased the toxicity of the three neonicotinoids, reduced the lifespan of adults, and decreased the number of nonviable nymphs produced by female adults. The metabolites AA, (±)11-HETE, and prostaglandin B1 are potential biomarkers in neonicotinoid-resistant M. persicae. MpTHEM6a may become a potential target for combating neonicotinoid-resistant M. persicae. [ABSTRACT FROM AUTHOR]

ABSTRACT The tri‐trophic interactions among five cabbage (Brassica oleracea var. capitata) cultivars—Copenhagen Market (CM), Red Acre (RA), Vertus Savoy (VS), Sugarloaf (SL) and Danish Ballhead (DBH)—a generalist aphid, Myzus persicae (Sulzer) and its parasitoid, Diaeretiella rapae McIntosh, were assessed. Copenhagen Market, known for its reported aphid resistance, recorded the fewest aphids (9.11 per plant; F = 6.50; df = 4, p < 0.01), followed closely by Red Acre (11.83 per plant), which was statistically similar. Upon aphid attack, all cultivars produced plant volatiles that influenced the attraction of the parasitoid, D. rapae. Copenhagen Market consistently showed a higher response across cultivar combinations, attracting 62.59%–67.50% of parasitoids. It also recorded a higher parasitisation rate (39.9%; F = 5.94; df = 4/20, p < 0.01) in a multiple‐choice test. The results indicate that cabbage cultivars employ both constitutive and induced resistance, as aphid‐resistant cultivars were also found to be more attractive to parasitoids. In addition to plant odour cues, factors such as plant colour, texture and host aphid kairomones can influence the orientation and parasitisation by D. rapae. [ABSTRACT FROM AUTHOR]

Piercing/sucking insects such as green peach aphid (GPA) (Myzus persicae) cause direct damage by obtaining phloem nutrients and indirect damage by spreading plant viruses. To investigate the response of peach trees (Prunus persica) to aphids, the leaf transcriptome and metabolome of two genotypes with different sensitivities to GPA were studied. The gene expression of aphid-susceptible plants infested with aphids was similar to that of control plants, whereas the gene expression of aphid-resistant plants infested with aphids showed strong induced changes in gene expression compared with control plants. Furthermore, gene transcripts in defense-related pathways, including plant–pathogen interaction, MAPK signaling, and several metabolic pathways, were strongly enriched upon aphid infestation. Untargeted secondary metabolite profiling confirmed that aphid infestation induced larger changes in aphid-resistant than in aphid-susceptible peaches. Consistent with transcriptomic alterations, nine triterpenoids showed highly significant GPA-induced accumulation in aphid-resistant peaches, whereas triterpenoid abundance remained predominantly unchanged or undetected in aphid-susceptible peaches. Furthermore, some types of transcription factors (including WRKYs, ERFs, and NACs) were strongly induced upon GPA infestation in aphid-resistant, but not in aphid-susceptible peaches. These results suggested that the accumulation of specialized triterpenoids and the corresponding pathway transcripts may play a key role in peach GPA resistance. [ABSTRACT FROM AUTHOR]

The field experiment was undertaken at the Experimental Farm, Department of Entomology, School of Agricultural Sciences (SAS), Medziphema Campus, Nagaland University, during the period of November 2021 to February 2022 to study the efficacy of certain bio-pesticides against major insect pests of broccoli. The experiment was conducted using Randomized Block Design (RBD) with six treatments including control and replicated four times. The study revealed that Indian cabbage white, Pieris spp. and green peach aphid, Myzus persicae have been found to be the major insect pest in broccoli. It is recorded that the highest (73.49%) population reduction of M. persicae was obtained from the plot treated with emamectin benzoate 5% SG and the highest (90.16%) population reduction of Pieris spp. was recorded on the plot treated with spinosad 45% SG. Therefore, the study concluded that use of bio-pesticides offers a great efficacy in controlling the pest and diminish the pesticides related issue. [ABSTRACT FROM AUTHOR]

The predatory gall midge, Aphidoletes aphidimyza (Rondani), and tobacco aphid cocoon wasp, Aphidius gifuensis Ashmead, are important natural enemies of Myzus persicae (Sulzer) (Hemiptera: Aphididae). Predation by A. aphidimyza and A. gifuensis can regulate M. persicae ; however, how interspecific interference competition affects their foraging efficiency is unknown. Here, we investigated the consumption and parasitization abilities of A. aphidimyza 3rd instar larva and A. gifuensis adults under various conditions. Consumption of parasitized aphids by A. aphidimyza 3rd instar larvae was significantly lower than that of nonparasitized controls, with a substantial increase in handling time. The presence of A. gifuensis adults did not significantly affect the predation capacity of A. aphidimyza larvae. Relative to controls, A. aphidimyza larvae predation trace (PT) and imago activity significantly decreased A. gifuensis parasitism rates at different aphid densities. Further, A. aphidimyza larvae PT increased the A. gifuensis handling time of M. persicae , whereas the presence of A. aphidimyza adults had the opposite effect. Coexistence with heterospecific natural enemies reduced the parasitic capacity of A. gifuensis , whereas A. aphidimyza larvae predation capability was influenced to a lesser extent. Our results demonstrate that intraguild interactions strongly influence the predatory and parasitic efficacy of A. aphidimyza and A. gifuensis , although the effect on A. gifuensis was more pronounced. For effective biological control of M. persicae using A. aphidimyza and A. gifuensis , we recommend releasing A. aphidimyza first to mitigate intraguild predation and enhance the overall success of the pest control program. [ABSTRACT FROM AUTHOR]

BACKGROUND: Body‐color polymorphisms in insects are often explained by environmental selective advantages. Differential fitness related to body coloration has been demonstrated in Myzus persicae (Sulzer): performance of the red morph is in general better than that of the green morph on tobacco plants. However, the molecular mechanism involved is largely unclear. RESULTS: Here we showed that the red morph of M. persicae had higher expression of a carotenoid desaturase CarD763 in the whole body, salivary gland and saliva relative to the green morph. Also, 18% individuals displayed faded red body color 5 days post dsCarD763 treatment. Furthermore, knockdown of CarD763 in the red morph significantly prolonged the time needed to locate phloem and shortened the duration of phloem feeding. Honeydew production and survival rate decreased as well. In contrast, overexpression of CarD763 in tobacco leaves facilitated aphid feeding, enhanced honeydew production and improved the survival rate of aphids. Compared with those fed by dsGFP aphids, plants infested by dsCarD763‐treated aphids had higher ROS accumulation, lower lycopene content and photosynthetic rate, and maximum photon quantum yield. The reverse was true when plants overexpressed CarD763. CONCLUSION: These findings demonstrated that CarD763, a red morph‐specific salivary protein, could enhance aphid feeding and early colonization by promoting plant photosynthesis. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the lethal effect of 1 x 108 conidia mL-1 concentration of local Beauveria bassiana isolates (ET 10, BMAUM-M6-4, Bb 1) against M. persicae under laboratory conditions. For the spraying method, B. bassiana isolates was applied to M. persicae nymphs with a hand spray. In this context, the experiments were carried out in a randomized plots experimental design with ten replicates with ten nymphs in each Petri plate. After the applications, the number of live individuals was recorded by counting the 1st, 3rd, 5th and 7th days and the percentage mortality rate was calculated. On the third and fifth days of the experiment, the highest mortality rates of 64 and 95% were recorded for the Bb 1 isolate of B. bassiana, respectively. In the seventh day counts, 100% mortality rates were determined for Bb 1 and ET 10 isolates and 99% for the BMAUM-M6-4 isolate. In addition, the mortality date (LT50) values were calculated as 3.62 days for ET 10 isolate, 3.60 days for BMAUM M6-4 isolate, and 2.93 days for Bb 1 isolates, respectively. As a result, it is thought that B. bassiana isolates can be used in biological control practices within the scope of integrated pest management program against M. persicae. [ABSTRACT FROM AUTHOR]

Myzus persicae and Aphis gossypii (Hemiptera: Aphididae) are two of the most significant aphid species acting as vectors for plant viruses in vegetable crops worldwide. This work provides new knowledge relating the persistence (including population growth and survival) and impact on aphid probing and feeding behaviour of plant essential oil-derived products. Modifications in M. persicae behaviour (EPG results) were noted in plants treated with 0.2% nanoemulsions of distilled lemon oil: (1) the non-probing activity lasted longer, (2) both non-phloematic probing and phloem ingestion activities of aphids were shorter, and (3) xylem ingestion activity and the time taken to achieve sustained phloem ingestion appear to be longer. Finally, a slight increase was also observed in the mean duration of the non-probing activity of M. persicae on plants treated with 0.2% nanoemulsions of farnesol. When pepper plants were sprayed with a 0.2% nanoemulsion of farnesol with Tween 80® (1:2), the population growth of M. persicae colonies on treated plants was slower (40 aphids/plant) than on controls (60 aphids/plant) up to the day seven. The slope of the aphid population growth line corresponding to the formulated mixture of bioactive volatiles was lower (2.26 b) and statistically significant in comparison with the control (7.09 a), probably due to a controlled-release effect up to day 14. No systemic effects were obtained for the bioactive volatiles tested. [ABSTRACT FROM AUTHOR]

A growing challenge in canola (Brassica napus L.) production globally is the management of aphid pests, particularly species that are resistant to insecticides. Aphid pests of canola damage plants through direct feeding and virus transmission, with turnip yellows virus being particularly economically damaging. Integrated Pest Management, a strategy now employed by many growers to reduce the risk of insecticide resistance, requires forward planning and monitoring. Improved risk predictions can be used to help growers limit insecticide spraying by targeting high‐risk regions and/or periods. Within Australia, autumnal aphid flights coincide with the critical risk period for virus infestations in canola. In this study, we used an extensive database accumulated from 6 years of surveys collected from more than 200 canola fields across southern Australia with supervised machine learning models to predict aphid movements in autumn‐early winter as a function of environmental factors. We found: (i) our models achieve very high predictive accuracy when validated on untrained data; (ii) aphid movements are influenced by a combination of daily temperature and wind regimes as well as 'green bridge' effects mediated by summer rainfall patterns; and (iii) higher aphid capture rates in sticky traps are correlated with a higher probability of the aphids being carriers of turnip yellows virus. Taken together these results suggest that growers can use the outputs from predictive models to forecast aphid outbreaks in the early growing season and derive useful rules of thumb around the environmental conditions during which canola crops are at a greater risk of turnip yellows virus transmission. [ABSTRACT FROM AUTHOR]

BACKGROUND: Understanding how parasitoids respond to temperature is crucial for improving biological control strategies under the context of global warming. This study examined the suitability of Myzus persicae and its parasitoid Aphidius gifuensis to varying temperature conditions, as well as the stage‐specific response of A. gifuensis to high temperatures. RESULTS: High temperatures had a significant impact on the both M. persicae and A. gifuensis. When exposed to 36°C, M. persicae developed more slowly and produced smaller adults compared to control, regardless of the duration of exposure (2, 4 or 6 h); additionally, the survival rate of M. persicae nymphs sharply decreased under these conditions. Exposure to 36°C for 4 h negatively impacted the development of A. gifuensis. Female parasitoids exposed to 32°C developed into smaller adults, whereas males exposed to all three temperature levels were smaller compared to control group. Female parasitoids exposed to high temperatures, regardless of the specific heat level and duration, exhibited reduced longevity and decreased fecundity. None of the parasitoids exposed to 36°C for 6 h daily developed into adults. Heat treated during early developmental stages (2 and 4 days old) had a greater influence on parasitoid development, whereas heat treatment at 4 and 6 days old had a more significant impact on its fecundity. CONCLUSION: High temperatures not only directly affected the performance of A. gifuensis, but also exerted indirect effects by influencing the quality of the host aphids M. persicae. The deleterious effects of high temperature on larvae can persist into the adult stage, affecting the longevity and reproduction of adults. These findings are important for the utilization of A. gifuensis in the control of M. persicae in warming environments. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The green peach aphid (Myzus persicae) is a severe agricultural crop pest that has developed resistance to most current control methods, requiring the urgent development of novel strategies. Plant proteinase inhibitors (PINs) are small proteins that protect plants against pathogens and/or herbivores, likely by preventing efficient protein digestion. RESULTS: We identified 67 protease genes in the transcriptomes of three M. persicae lineages (USDA‐Red, G002 and G006). Comparison of gene expression levels in aphid guts and whole aphids showed that several proteases, including a highly expressed serine protease, are significantly overexpressed in the guts. Furthermore, we identified three genes encoding serine protease inhibitors (SerPIN‐II1, 2 and 3) in Nicotiana benthamiana, which is a nonpreferred host for M. persicae. Using virus‐induced gene silencing (VIGS) with a tobacco rattle virus (TRV) vector and overexpression with a turnip mosaic virus (TuMV) vector, we demonstrated that N. benthamiana SerPIN‐II1 and SerPIN‐II2 cause reduced survival and growth, but do not affect aphid protein content. Likewise, SerPIN‐II3 overexpression reduced survival and growth, and serpin‐II3 knockout mutations, which we generated using CRISPR/Cas9, increased survival and growth. Protein content was significantly increased in aphids fed on SerPIN‐II3 overexpressing plants, yet it was decreased in aphids fed on serpin‐II3 mutants. CONCLUSION: Our results show that three PIN‐IIs from N. benthamiana, a nonpreferred host plant, effectively inhibit M. persicae survival and growth, thereby representing a new resource for the development of aphid‐resistant crop plants. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: The interactions among plant viruses, insect vectors, and host plants have been well studied; however, the roles of insect viruses in this system have largely been neglected.We investigated the effects of MpnDV infection on aphid and PVY transmission using bioassays, RNA interference (RNAi), and GC‐MS methods and green peach aphid (Myzus persicae (Sulzer)), potato virus Y (PVY), and densovirus (Myzus persicae nicotianae densovirus, MpnDV) as model systems.MpnDV increased the activities of its host, promoting population dispersal and leading to significant proliferation in tobacco plants by significantly enhancing the titer of the sesquiterpene (E)‐β‐farnesene (EβF) via up‐regulation of expression levels of the MpFPPS1 gene. The proliferation and dispersal of MpnDV‐positive individuals were faster than that of MpnDV‐negative individuals in PVY‐infected tobacco plants, which promoted the transmission of PVY.These results combined showed that an insect virus may facilitate the transmission of a plant virus by enhancing the locomotor activity and population proliferation of insect vectors. These findings provide novel opportunities for controlling insect vectors and plant viruses, which can be used in the development of novel management strategies. [ABSTRACT FROM AUTHOR]

Potato aphids are the most destructive sucking insect pests of potato crops worldwide and cause financial losses to potato crops. Accurate identification is most famous for the implementation of an appropriate control strategy. DNA barcoding is the most accurate and reliable technique for the identification of aphid species. Therefore, an experiment was conducted based on DNA barcoding of aphid species. Aphid specimens were collected from different districts of Punjab, Pakistan. Cytochrome C Oxidase I (CO1) gene primers were used for the amplification of conserved sequence mtDNA of the collected specimens. The results revealed that one species of potato aphid identified as Macrosiphum euphorbiae with 97–99% good query coverage and 97–100% similarity with other potato aphid species present on the NCBI database and the other species identified as Myzus persicae with good query coverage from 95 to 100%. In contrast, the similarity index observed from 86 100% related to that of available on the NCBI database. The phylogenetic studies showed that M. euphorbiae shares the same cluster with M. euphorbiae isolate Shimla_A7, M. euphorbia isolate 10BBCHEM-0973, M. euphorbia, and M. euphorbia voucher. On the other hand, M. persicae shares the same cluster with M. persicae voucher APOM13 and M. persicae voucher APOL13. Aphids are becoming dangerous pests. Therefore, this study will help us to develop species-specific M. euphorbiae and M. persicae control measures. [ABSTRACT FROM AUTHOR]

Ensuring the safety of insecticides to natural enemy insects of pests is crucial for integrating chemical and biological control strategies. Broflanilide, a novel meta-diamide insecticide, exhibits high insecticidal activity against Myzus persicae (Sulzer) (Hemiptera: Aphididae). To integrate chemical and biological control against M. persicae , we assessed the toxicity of broflanilide to Aphidius gifuensis , and evaluated its safety and sublethal effects. The LC10, LC25, and LC50 values of broflanilide against A. gifuensis were 0.733 mg/L, 1.613 mg/L, and 3.852 mg/L, respectively. The selectivity toxicity ratio of broflanilide to A. gifuensis was 1.516, indicating higher toxicity to M. persicae compared to A. gifuensis. The risk quotient of broflanilide to A. gifuensis adults was 6.18. The percent reduction in the emergence of the parasitoid pupae was −1.15, with a risk grade of 1. The sublethal concentration of broflanilide had no significant influence on the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R 0), and mean fecundity (F) of A. gifuensis in the F1 generation. The mean generation time (T) increased by 0.51 days and 0.39 days in the LC10 and LC25 treatments, respectively; the difference between LC10 treatment and the control was significant, while the difference between LC25 treatment and the control was not significant. The results showed that the sublethal concentration of broflanilide did not have a significant inhibitory effect on the population growth of A. gifuensis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Myzus persicae, a serious sap‐sucking pest of a large variety of host plants in agriculture, is traditionally controlled using chemical insecticides but there is interest in using biopesticides as restrictions are increasingly placed on the use of broad‐spectrum pesticides. RESULTS: Here, we show that in Petri dish experiments, high concentrations of the fungal entomopathogen Beauveria bassiana led to rapid mortality of M. persicae, although at a low concentration (1 × 104 conidia mL−1) there is a hormetic effect in which survival and fecundity are enhanced. Hormetic effects persisted across a generation with reduced development time and increased fecundity in the offspring of M. persicae exposed to B. bassiana. The whole‐plant experiment points to a hormetic effect being detected in two out of three tested lines. The impact of these effects might also depend on whether M. persicae was transinfected with the endosymbiont Rickettsiella viridis, which decreases fecundity and survival compared with aphids lacking this endosymbiont. This fecundity cost was ameliorated in the generation following exposure to the entomopathogen. CONCLUSION: Although B. bassiana is effective in controlling M. persicae especially at higher spore concentrations, utilization of this entomopathogen requires careful consideration of hormetic effects at lower spore concentrations, and further research to optimize its application for sustainable agriculture is recommended. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Afidopyropen is a novel insecticide with high selectivity between sucking insects such as the peach aphids Myzus persicae and natural enemies like the seven‐spotted lady beetle Coccinella septempunctata. However, the mechanisms of selective action for afidopyropen remain unknown. RESULTS: The LC50 values of afidopyropen to the 1st–4th instar larvae and adult C. septempunctata were 372‐ to more than 7267‐fold higher than that to adult M. persicae. Though the activity of cytochrome P450s in M. persicae was 6.1‐ to 7.5‐fold higher than that in C. septempunctata, the latter has much higher activities of carboxylesterase (CarEs) and glutathione S‐transferases (GSTs), and the crude enzyme of C. septempunctata and M. persicae showed similar metabolism efficiency to afidopyropen. Molecular docking results demonstrated that afdopyropen showed higher binding affinity to the vanilloid‐type transient receptor potential (TRPV) channel of M. persicae (−9.1 kcal/mol) than to that of C. septempunctata (−8.2 kcal/mol). And the EC50 value of afdopyropen to the TRPV channel of C. septempunctata (41 360 nM) was 19 885‐fold higher than that in M. persicae (2.08 nM). CONCLUSIONS: Our results demonstrated that the significantly different sensitivity of M. persicae and C. septempunctata TRPV channel to afidopyropen play a key role in the high selectivity of afidopyropen. These findings provide new insights into the selective mechanisms of afidopyropen against insect pests and natural enemies as well as the theory support for coordinated application of chemical control and biological control. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: RNA interference (RNAi) has emerged as an efficient technology for pest control by silencing the essential genes of targeted insects. Owing to its nucleotide sequence‐guided working mechanism, RNAi has a high degree of species‐specificity without impacts on non‐target organisms. However, as plants are inevitably under threat by two or more insect pests in nature, the species‐specific mode of RNAi‐based technology restricts its wide application for pest control. In this study, we artificially designed an intermediate dsRNA (iACT) targeting two β‐Actin (ACT) genes of sap‐sucking pests Bemisia tabaci and Myzus persicae by mutual correction of their mismatches. When expressing hairpin iACT (hpiACT) from tobacco nuclear genome, transgenic plants are well protected from both B. tabaci and M. persicae, either individually or simultaneously, as evidenced by reduced fecundity and suppressed ACT gene expression, whereas expression of hpRNA targeting BtACT or MpACT in transgenic tobacco plants could only confer specific resistance to either B. tabaci or M. persicae, respectively. In sum, our data provide a novel proof‐of‐concept that two different insect species could be simultaneously controlled by artificial synthesis of dsRNA with sequence optimization, which expands the range of transgenic RNAi methods for crop protection. [ABSTRACT FROM AUTHOR]

Simple Summary: The selection of an appropriate diet is a key component of methods for the mass rearing of biocontrol agents. It is known that feeding on mixed, alternating, or changing foods often favor insect development. We investigated the effects of various combinations of high-quality (the green peach aphid) and low-quality (eggs of the grain moth) foods on the development of a predatory ladybird Cheilomenes propinqua. The benefits of mixed foods to larval development were only found in some treatments with limited supplies of aphids. Feeding on various combined diets never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids. We conclude that if necessary (for example, in the case of temporary shortage or a lack of aphids in mass rearing facilities or in the case of preventing release of adults for biological control of pests in greenhouses), C. propinqua larvae can be fed with grain moth eggs by replacing, mixing, or alternating with aphids, although this will result in a decrease in pre-adult survival, rate of development, and the size of emerging adults. On the other hand, even a minimal addition of aphids can have a substantial positive effect on larvae fed with grain moth eggs. Feeding on mixed, alternating, or changing diets often favor insect development. With the aim to optimize mass rearing and use for the biological control of insect pests, we investigated the effects of various combinations of high-quality (the green peach aphid Myzus persicae) and low-quality (eggs of the grain moth Sitotroga cerealella) foods on the larval development of a predatory ladybird Cheilomenes propinqua. In the first experiment, eggs and aphids were mixed in different proportions; in the second experiment, larvae switched from feeding on aphids to feeding on eggs. Although the beneficial additive effect of mixed foods was detected in some treatments with limited diets, feeding on various combinations of eggs with aphids never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids. For the practice of biological control, we conclude that, if necessary (for example, in the case of temporary shortage or a lack of aphids in mass rearing facilities or in the case of preventing release of C. propinqua adults in greenhouses), C. propinqua larvae can be fed with grain moth eggs by replacing, mixing, or alternating with aphids, although this will inevitably result in a proportional decrease in pre-adult survival, rate of development, weight, and size of the emerging adults. On the other hand, even a minimal addition of aphids can have a substantial positive effect on larvae fed with grain moth eggs. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Bacillus thuringiensis (Bt) and its crystal toxin or δ‐endotoxins (Cry) offer great potential for the efficient control of crop pests. A vast number of pests can potentially infect the same host plant, either simultaneously or sequentially. However, no effective Bt‐Cry protein has been reported to control both aphids and plant parasitic nematodes due to its highly specific activity. RESULTS: Our study indicated that the Cry5Ba2 protein was toxic to the green peach aphid Myzus persicae, which had a median lethal concentration (LC50) of 9.7 ng μL−1 and fiducial limits of 3.1–34.6 ng μL−1. Immunohistochemical localization of Cry5Ba2 revealed that it could bind to the apical tip of microvilli in midgut regions. Moreover, transgenic tobacco plants expressing Cry5Ba2 exhibited significant resistance to Myzus persicae, as evidenced by reduced insect survival and impaired fecundity, and also intoxicated the Meloidogyne incognita as indicated by a decrease in galls and progeny reproduction. CONCLUSION: In sum, we identified a new aphicidal Bt toxin resource that could simultaneously control both aboveground and belowground pests, thus extending the application range of Bt‐based strategy for crop protection. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The occurrence and increased dispersion of plant viruses and insect vectors are serious global threat to the production of agricultural crops. Facing novel pathogenic plant viruses, the ability to accurately identify plant virus species, and understand the interaction between plant viruses, host plants and their insect vectors would provide an important basis for formulating effective plant virus control measures. In this study, we explored the transmission mechanism, pathogenic symptoms, host range and the interactions between virus and aphid vectors of a novel polerovirus from Nicotiana tabacum, named Tobacco yellow virus (TYV). The results indicate that TYV can be transmitted by Myzus persicae in a persistent manner, and cause yellowing and shrinking of tobacco leaves. TYV can successfully infect a total of 9 plant species belonging to 3 families. The effect of TYV-infected tobacco plants on M. persicae behavior and life characteristics was found to be stage-dependent. TYV can directly and indirectly manipulate the performance and life history traits of M. persicae vectors to promote their own transmission. These results provide a certain theoretical basis for the possibility of control strategies of the virus, and the in-depth exploration of the interaction among plant virus, vector aphid and host plants.

BACKGROUND: To improve integrated pest management (IPM) performance it is essential to assess pesticide side effects on host plants, insect pests, and natural enemies. The green peach aphid (Myzus persicae Sulzer) is a major insect pest that attacks various crops. Aphidius gifuensis is an essential natural enemy of M. persicae that has been applied effectively in controlling M. persicae. Thiamethoxam is a neonicotinoid pesticide widely used against insect pests. RESULTS: The current study showed the effect of thiamethoxam against Solanum tuberosum, M. persicae, and A. gefiuensis and the physiological and molecular response of the plants, aphids, and parasitoids after thiamethoxam application. Thiamethoxam affected the physical parameters of S. tuberosum and generated a variety of sublethal effects on M. persicae and A. gefiuensis, including nymph development time, adult longevity, and fertility. Our results showed that different thiamethoxam concentrations [0.1, 0.5, and 0.9 μm active ingredient (a.i.)/L] on different time durations (2, 6, and 10 days) increased the antioxidant enzyme activities SOD, POD, and CAT of S. tuberosum, M. persicae, and A. gefiuensis significantly compared with the control. Our results also showed that different thiamethoxam concentrations (0.1, 0.5, and 0.9 μm a.i./L) on different time durations (2, 6, and 10 days) increased the expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione‐S‐transferase (GST) genes of S. tuberosum, M. persicae, and A. gefiuensis compared with the control. CONCLUSION: Our findings reveal that using thiamethoxam at suitable concentrations and time durations for host plants and natural enemies may enhance natural control through the conservation of natural enemies by overcoming any fitness disadvantages. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: RNA interference (RNAi) is the sequence‐dependent suppression of gene expression by double‐stranded RNA (dsRNA). This is a promising strategy for the control of insect pests because dsRNA can be rationally designed to maximize efficacy and biosafety, the latter by using sequences that are found in target pests but are safe for non‐target insects. However, this has yet to be optimized in aphids, destructive sap‐sucking pests that also transmit plant viruses. We used the green peach aphid (Myzus persicae) as a case study to optimize the efficiency of RNAi by applying a novel fusion dsRNA design. RESULTS: Comparative transcriptomics revealed a number of genes that are induced in feeding aphids, and eight candidate genes were chosen as RNAi targets. To improve RNAi efficiency, our fusion dsRNA design approach combined optimal gene fragments (highly conserved in several aphid species but with less homology in beneficial insects such as the predator ladybeetle Propylea japonica) from three candidate genes. We compared this RNAi‐based biological control approach with conventional chemical control using imidacloprid. We found that the fusion dsRNA strategy inhibited the aphid population to a significantly greater extent than single‐target RNAi and did not affect ladybeetle fitness, allowing an additive effect between RNAi and natural predation, whereas imidacloprid was harmful to aphids and ladybeetles. CONCLUSION: Our fusion dsRNA design approach enhances the ability of RNAi to control aphids without harming natural predators. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Plant fertilization may impact directly on insect pest behavior and biology. Fertilization may be accomplished by using synthetic mineral or organic fertilizers. The effect of different doses of boiled hen chicken manure, Penergetic®, Bokashi compound and mineral fertilizer on the adult population of Bemisia tabaci and Myzus persicae on collards leaves were evaluated. The experiment was conducted in the greenhouse using the treatments: Bokashi, Penergetic® bioactivator, 2.5%, 5%, and 7.5% of solution of boiled manure, mineral fertilization and control. The number of insects was counted directly on the leaves, and the nitrogen, potassium content, and total phenolic compound in the leaves were determined. Higher populations of Bemisia tabaci and M. persicae were observed on NPK-fertilized plants compared to other treatments. Higher levels of nitrogen foliar were found for Bokashi-fertilized plants; and higher concentrations of total phenolic compounds were found in the control. A negative correlation between total phenolics and B. tabaci was established suggesting the importance of these compounds in the species development. The results indicate the importance of the source of the fertilization for sustainable pest management. [ABSTRACT FROM AUTHOR]

Wing dimorphism is regarded as an important phenotypic plasticity involved in the migration and reproduction of aphids. However, the signal transduction and regulatory mechanism of wing dimorphism in aphids are still unclear. Herein, the optimal environmental conditions were first explored for inducing winged offspring of green peach aphid, and the short photoperiod was the most important environmental cue to regulate wing dimorphism. Compared to 16 L:8 D photoperiod, the proportion of winged offspring increased to 90% under 8 L:16 D photoperiod. Subsequently, 5 differentially expressed microRNAs (miRNAs) in aphids treated with long and short photoperiods were identified using small RNA sequencing, and a novel miR‐3040 was identified as a vital miRNA involved in photoperiod‐mediated wing dimorphism. More specifically, the inhibition of miR‐3040 expression could reduce the proportion of winged offspring induced by short photoperiod, whereas its activation increased the proportion of winged offspring under long photoperiod. Meanwhile, the expression level of miR‐3040 in winged aphids was about 2.5 times that of wingless aphids, and the activation or inhibition of miR‐3040 expression could cause wing deformity, revealing the dual‐role regulator of miR‐3040 in wing dimorphism and wing development. In summary, the current study identified the key environmental cue for wing dimorphism in green peach aphid, and the first to demonstrate the dual‐role regulator of miR‐3040 in photoperiod‐mediated wing dimorphism and wing development. [ABSTRACT FROM AUTHOR]

Simple Summary: The present study explores the impact of alternative prey on predator–prey dynamics in two contexts, without and with intraguild predation (IGP). It was found that without IGP, G. punctipes displayed a generalized functional response regardless of the alternative prey. However, under IGP conditions, the predator's functional response shifted to Type II, but the alternative prey did affect this response and it turned to a generalized type. In both contexts, handling times increased and consumption of the focal prey decreased as the density of the alternative prey increased. The presence of parasitized whitefly nymphs notably affected predator–prey dynamics, probably due to changes in prey characteristics. In biological control, joint releases of predators and parasitoids are standard. However, intraguild predation (IGP) can occur when a predator attacks a parasitoid, potentially affecting pest control dynamics. In addition to the focal prey (FP), Trialeurodes vaporariorum, the intraguild predator (IG-predator) Geocoris punctipes can consume the parasitoid Eretmocerus eremicus (IG-prey). In this IGP context with multiple prey, an alternative prey (AP), like the aphid Myzus persicae, may influence interactions. Theory predicts that, in simple interactions, a predator's functional response (FR) to the FP changes with the presence of an AP. However, whether this holds in an IGP context is unknown. In this study, we empirically tested that prediction. Our results show that without IGP, G. punctipes exhibits a generalized FR with and without AP. Nevertheless, with IGP, the predator exhibited a Type II FR at low and high AP densities, increasing pressure on the FP and potentially favoring short-term biological control strategies. However, when 25 AP were offered, the predator's response shifted, underscoring the importance of monitoring AP densities to prevent potential disruptions in FP control. In both contexts, the increase in AP produced a handling time increase and a decrease in consumption rate. These results indicate that the theoretical prediction of the effect of AP on the FR is met only under specific conditions, and the complexity of multitrophic interactions must be considered. [ABSTRACT FROM AUTHOR]

Background: Failures in controlling Myzus persicae by pyrethroids and carbamates have been observed in Czechia since 2018. Eleven populations collected from Czech oilseed rape fields during 2018–2021 were tested for susceptibility to 11 insecticides. The presence of a single nucleotide polymorphism (SNP) leading to knockdown resistance in M. persicae populations was screened using allelic discriminating quantitative real‐time polymerase chain reaction (qPCR). The presence of mutations related with the resistance of M. persicae to pyrethroids and carbamates was detected by sequencing paratype voltage‐gated sodium channel and acetylcholinesterase 2 genes, respectively. Results: Resistance to alpha‐cypermethrin and pirimicarb was detected in most of the tested populations. The L1014F mutation was detected in 44.5% of M. persicae individuals surviving the field‐recommended dose of alpha‐cypermethrin. Sequencing of partial para gene for paratype voltage‐gated sodium channel detected five different SNPs leading to four amino acid substitutions (kdr L1014F; s‐kdr M918L; s‐kdr M918T; and L932F). No pyrethroid‐sensitive genotype was detected. The S431F amino acid substitution conferring resistance to carbamates was detected in 11 of 20 individuals with different pyrethroid‐resistance genotypes. Conclusion: Resistance of M. persicae to both pyrethroids and carbamates was detected in nine of 11 populations. High resistance of M. persicae was correlated with mutations of the sodium channel. Sulfoxaflor, flonicamid, and spirotetramat are proposed as effective compounds to control pyrethroid‐ and carbamate‐resistant populations of M. persicae. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

An introduction to high‐speed photography and its entomological impact is provided, emphasizing the importance of high frame rates and high resolution. The take‐off and free flight of Drepanosiphum platanoidis and Myzus persicae were studied in still air using high‐speed photography in HD. The wing tip and body posture were tracked to show how they are displaced during each wingbeat cycle. The important structural elements of the wing are described. The wingbeat is driven by a reinforced leading edge, the pterostigma and costa. The remainder of the coupled fore‐ and hindwing acts as a single aerofoil that deforms during flight, due to sparse venation and a lack of cross veins. During flight, aphids use a ‘near clap and fling’ mechanism with a body pitch close to 90°. Rapid acceleration about the thoracic lateral axis into wing reversal generates enough lift for take‐off, typically within the first or second wingbeat. Unique footage shows that aphids demonstrate a high degree of flight control and manoeuvrability in the lab, occasionally using forward and inverted flight, two flight modes that are otherwise poorly known. While research into the impact of turbulent convection is needed, we posit that the strength of atmospheric forces presents a formidable challenge to aphid migrants. Above the flight boundary layer, migrating aphids may not easily oppose upwardly moving air, although if used, ‘frozen flight’ may cause them to descend on average. We evaluate five devices for insect flight research. [ABSTRACT FROM AUTHOR]

【Objective】 Peach aphid (Myzus persicae) is an important vector of cucumber mosaic virus (CMV), and the effector MpC002 plays a key role in the feeding process. CMV and MpC002 are both present in aphid saliva, but little is known about their interaction and how MpC002 facilitate virus transmission. Therefore, this study aims to preliminarily investigate the mechanism by which CMV influences the expression of MpC002 for interfering the population growth of GPA. .【Method】 The CMV copy number was calculated by the standard curve y=-3.163 1x+39.763, via applying the absolute quantitative polymerase chain reaction (qPCR) 【Result】 The CMV content in the peach aphid fed with CMV-infected pepper reached the highest at 10 s, then the CMV content decreased gradually along with the feeding time, and its virulence acquisition process conformed to the characteristics of non-persistent transmission. In addition, the expressions of MpC002 in the peach aphids fed on CMV-infested peppers within 5 min-24 h significantly decreased to 37%-58%, compared with those before feeding. While feeding on CMV-infested peppers, the average developmental duration of third, fourth instar and the entire nymph stages were 1.58, 2.07 and 6.47 d, which were significantly longer than those fed on the untreated peppers (1.25 d, 1.47 d and 5.33 d) ; in contrast, the developmental duration of the first and second instars did not show significantly difference between CMV-infested and untreated peppers. The average laying period, the total peach aphid number and the average peach aphid in a single day were 10.03 d, 16.87 and 1.67, which were significantly shorter than those of untreated peppers (14.27 d, 39.73 and 2.82) . In addition, analysis of GPA life table parameters revealed that the net growth rate, intrinsic rate of increase, and finite rate of increase were 16.87, 0.21, and 1.21, respectively, which were significantly lower than those of peach aphids feeding on untreated peppers (39.73, 0.31, and 1.36, respectively), whereas the mean generation time (13.02 d) and the population doubling time (3.26 d) were both significantly longer than those of peach aphids feeding untreated peppers (12.00 d and 2.30 d) .【Conclusion】CMV significantly inhibited the expressions of MpC002, and then prolongated the developmental duration and decreased the reproduction, which in turn adversely affected its population growth. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tomato (Solanum lycopersicum L.) is an economically important vegetable crop around the globe. Tomato yellow leaf curling (TYLC) is the most devastating viral disease posing a serious threat to tomato production throughout the tropical and subtropical world. Induction of microbe‐mediated systemic resistance in plants has been of great interest in recent years as a novel microbiological tool in disease and insect pest management. This in‐vitro study aimed to determine the effectiveness of different strains (BB252, BB72 and ARSEF‐2860) of a hypocreal fungus Beauveria bassiana against TYLCV disease and aphid Myzus persicae. Potted tomato plants exogenously treated with conidial and filtrate suspensions of B. bassiana strains and of their partially purified or purified proteins were exposed to TYLCV inoculum and aphid M. persicae. RESULTS: Results showed a significant suppression of TYLCV disease severity index by the exogenous application of conidial, filtrate and protein treatments of all B. bassiana strains and this response was directly proportional to the treatment concentration. Similarly, mean fecundity rate of M. persicae was also significantly reduced by the highest concentration of ARSEF‐2860‐derived elicitor protein PeBb1, followed by the highest concentrations of BB252‐ and BB72‐derived partially purified proteins. Moreover, these B. bassiana‐derived proteins also caused a significant upregulation of most of the plant immune marker genes associated with plant defense. CONCLUSION: Overall, the study findings suggest that these B. bassiana strains and their partially purified or purified elicitor proteins could be effective biological tools for the management of TYLCV and aphid infestation on tomato plants. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Myzus persicae is a prevalent and serious pest in tobacco fields of Shandong province. Study on the population dynamics and spatial distribution of Myzus persicae in Shandong tobacco fields is of great significance for improvement of the accuracy of Myzus persicae prediction and effective prevention and control of this pest. In this study, the population dynamics were investigated in tobacco fields, and the spatial distribution characteristics were studied using five indexes of aggregation (clumping index I, patchiness index m*/m, Cassie index Ca, dispersion coefficient C, and negative binomial K) and two regression models(Iwao's regression and Taylor's power law). The results showed that the population dynamics of Myzus persicae showed a clear bimodal curve in the tobacco fields during 2020–2021, the first peak occurred from late May to early June and the second peak occurred from early to mid-July. On vertical distribution, the proportion of Myzus persicae on the upper leaves (49.07%-70.29%) was significantly higher than that on the middle leaves(27.64%-33.71%) and the lower leaves(1.64% – 19.85%). Data analysis showed that I>0, range: 1.733 2–42.703 0; m*/m>1, range: 2.368 3–10.414 2; Ca>0, range: 1.368 3– 9.414 2; C>1, range: 2.733 2 – 43.703 0; 01, α (0.190 57)>0. In Taylor's power law regression equation, lga(0.691 65)> 0, b(1.817 05)>1. The above results indicated that the distribution of the Myzus persicae population followed an aggregated pattern and the basic components of distribution were in individual groups during the investigation period. Theoretical sampling number were obtained from the spatial distribution parameters, and the resulting field sampling technique was determined: a Z-shaped sampling method was used in the tobacco fields, 5–10 tobacco plants were selected from each point and 2–4 upper and middle leaves were investigated for each tobacco plant. [ABSTRACT FROM AUTHOR]

Plants in the genus Erysimum produce both glucosinolates and cardenolides as a defense mechanism against herbivory. Two natural isolates of Erysimum cheiranthoides (wormseed wallflower) differed in their glucosinolate content, cardenolide content, and their resistance to Myzus persicae (green peach aphid), a broad generalist herbivore. Both classes of defensive metabolites were produced constitutively and were not further induced by aphid feeding. To investigate the relative importance of glucosinolates and cardenolides in E. cheiranthoides defense, we generated an improved genome assembly, genetic map, and segregating F2 population. The genotypic and phenotypic analysis of the F2 plants identified quantitative trait loci, which affected glucosinolates and cardenolides, but not the aphid resistance. The abundance of most glucosinolates and cardenolides was positively correlated in the F2 population, indicating that similar processes regulate their biosynthesis and accumulation. Aphid reproduction was positively correlated with glucosinolate content. Although the overall cardenolide content had little effect on aphid growth and survival, there was a negative correlation between aphid reproduction and helveticoside abundance. However, this variation in defensive metabolites could not explain the differences in aphid growth on the two parental lines, suggesting that processes other than the abundance of glucosinolates and cardenolides have a predominant effect on aphid resistance in E. cheiranthoides. [ABSTRACT FROM AUTHOR]

In a tritrophic context of plant–insect–entomopathogen, plants play important roles in modulating the interaction of insects and their pathogenic viruses. Currently, the influence of plants on the transmission of insect viruses has been mainly studied on baculoviruses and some RNA viruses, whereas the impact of plants on other insect viruses is largely unknown. Here, we identified a new densovirus infecting the green peach aphid Myzus persicae and tested whether and how host plants influence the transmission of the aphid densovirus. The complete single‐stranded DNA genome of the virus, M. persicae densovirus 2, is 5 727 nt and contains inverted terminal repeats. Transcription and phylogenetic analysis indicated that the virus was distinct from other a few identified aphid densoviruses. The virus abundance was detected highly in the intestinal tract of aphids, compared with the lower level of it in other tissues including head, embryo, and epidermis. Cabbage and pepper plants had no obvious effect on the vertical transmission and saliva‐mediated horizontal transmission of the virus. However, the honeydew‐mediated horizontal transmission among aphids highly depended on host plants (65% on cabbages versus 17% on peppers). Although the virus concentration in the honeydew produced by aphids between 2 plants was similar, the honeydew production of the infected aphids reared on peppers was dramatically reduced. Taken together, our results provide evidence that plants influence the horizontal transmission of a new densovirus in an aphid population by modulating honeydew secretion of aphids, suggesting plants may manipulate the spread of an aphid‐pathogenic densovirus in nature. [ABSTRACT FROM AUTHOR]

Hoverfly larvae are voracious predators of aphids but have limited dispersal capacity, so their survival depends critically on female selection of oviposition sites. For aphid control purposes, the ability of females to find small aphid colonies is especially valuable. In this study, the oviposition strategy and minimum aphid density triggering the oviposition of the American hoverfly, Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae), was compared with that of the aphid midge, Aphidoletes aphidimyza (Rondani, 1847) (Diptera: Cecidomyiidae), a predator commercially available in Canada as a reference. Oviposition behaviour was evaluated at densities of 0, 2, 5, 10, and 50 aphids per plant. This was tested on two economically significant plant/aphid systems: pepper plants infested by the green peach aphid, Myzus persicae (Sulzer 1776) (Hemiptera: Aphididae), and cucumber plants infested with the melon aphid, Aphis gossypii Glover 1877. Results showed that both predators lay their eggs in proportion to the size of the colony of aphids. Oviposition by E. americanus required a minimum density of 5 aphids on cucumber but only 2 on pepper, whereas for A. aphidimyza, it was also 5 aphids on cucumber, but 10 on pepper. The hoverfly laid more than twice as many eggs as A. aphidimyza on pepper. It also laid more eggs on pepper than on cucumber and the pattern is the opposite for A. aphidimyza. Therefore, the identity of the aphid‐host plant complex appears to modulate the oviposition of these predators. This study demonstrates the ability of E. americanus to respond to lower densities of aphids than A. aphidimyza early in the infestation on sweet pepper plants and shows that its oviposition rate is at least as effective as A. aphidimyza on cucumber. Consequently, these attributes of its oviposition behaviour indicate that E. americanus has great potential for use as an aphid biocontrol agent in these crops. [ABSTRACT FROM AUTHOR]

Plant viruses can modulate insect vector behaviour directly and/or indirectly by altering plant biochemistry. In many instances, such behavioural alterations increase the frequency of encounters between host and vector, leading to enhanced virus dispersal in ecosystems. In the current study using Cucumber mosaic virus (CMV), Capsicum annuum L. (Solanaceae), and Myzus persicae (Sulzer) (Hemiptera: Aphididae) as a pathosystem, we evaluated the direct and indirect effects of CMV on M. persicae biology and behavioural responses. Data showed that CMV indirectly modulates the aphid vector by providing fitness benefits to aphids, leading to enhanced aphid reproduction on CMV‐infected pepper plants in comparison with non‐infected C. annuum plants. Furthermore, CMV can also alter aphid behaviour directly by modulating the behavioural response of viruliferous aphids towards non‐infected plants. We demonstrate that CMV directly and indirectly modulates the insect vector thereby enhancing its transmission in agroecosystems. [ABSTRACT FROM AUTHOR]

Despite the known benefits of integrated pest management, adoption in Australian broadacre crops has been slow, in part due to the lack of understanding about how pests and natural enemies interact. We use a previously developed process-based model to predict seasonal patterns in the population dynamics of a canola pest, the green peach aphid (Myzus persicae), and an associated common primary parasitic wasp (Diaeretiella rapae), found in this cropping landscape. The model predicted aphid population outbreaks in autumn and spring. Diaeretiella rapae was able to suppress these outbreaks, but only in scenarios with a sufficiently high number of female wasps in the field (a simulated aphid:wasp density ratio of at least 5:1 was required). Model simulations of aphid-specific foliar pesticide applications facilitated biological control. However, a broad-spectrum pesticide negated the control provided by D. rapae, in one case leading to a predicted 15% increase in aphid densities compared to simulations in which no pesticide was applied. Biological and chemical control could therefore be used in combination for the successful management of the aphid while conserving the wasp. This modelling framework provides a versatile tool for further exploring how chemical applications can impact pests and candidate species for biological control. [ABSTRACT FROM AUTHOR]

Myzus persicae is an important pest that has developed resistance to nearly all currently used insecticidal products. The employment of insecticide synergists is one of the effective strategies that need to be developed for the management of this resistance. Our study showed that treatment with a combination of the antibiotic, rifampicin, with imidacloprid, cyantraniliprole, or clothianidin significantly increased their toxicities against M. persicae, by 2.72, 3.59, and 2.41 folds, respectively. Rifampicin treatment led to a noteworthy reduction in the activities of multifunctional oxidases (by 32.64%) and esterases (by 23.80%), along with a decrease in the expression of the CYP6CY3 gene (by 58.57%) in M. persicae. It also negatively impacted the fitness of the aphids, including weight, life span, number of offspring, and elongation of developmental duration. In addition, bioassays showed that the combination of rifampicin and a detoxification enzyme inhibitor, piperonyl butoxide, or dsRNA of CYP6CY3 further significantly improved the toxicity of imidacloprid against M. persicae, by 6.19- and 7.55-fold, respectively. The present study suggests that development of active ingredients such as rifampicin as candidate synergists, show promise to overcome metabolic resistance to insecticides in aphids.

AbstractAphids (Hemiptera: Aphididae) are herbivorous insects which deprive plants of nutrients by feeding on the phloem sap and transmission of plant viruses. In the present study, the susceptibility of selected white-berried grapevine (Vitis spp.) cultivars “Aurora”, “Bianca”, “Muskat Letni” and “Solaris” to the black bean aphid (Aphis fabae Scop.) and the green peach aphid (Myzus persicae (Sulz.) was evaluated using the Electrical Penetration Graph (EPG) technique. The content of major flavonoids and stilbenoids in grapevine leaves and leaf anatomy parameters that might have affected aphid probing were also analyzed. Based on the success rate in reaching the phloem vessels and feeding on phloem sap, the studied grapevine cultivars can be assigned to various groups of susceptibility. Cultivars “Bianca” and “Muskalt Letni” are susceptible to A. fabae and M. persicae, respectively (aphids reach phloem phase and show short bouts of sap ingestion); “Muskat Letni” shows low susceptibility to A. fabae, while “Aurora” and “Bianca” to M. persicae (only 50% aphids reach phloem phase and no sap ingestion occurs); “Solaris” is resistant to A. fabae and M. persicae (no phloem phase present). Anatomical structure of leaves was similar in all cultivars and no mechanical barriers for aphid probing were observed. However, the content of individual flavonoids and silbenoids differed among cultivars. We hypothesize that the high content of piceid in the leaves of “Solaris” may be responsible for the rejection of this cultivar by both aphid species. The study demonstrated that the risk of the direct damage due to A. fabae and M. persicae feeding on grapevines is low. However, considering the intense aphid probing activity within leaf epidermis and mesophyll, A. fabae and M. persicae may pose a serious threat as vectors of non-persistent and semi-persistent viruses to white-berried grapevines.

Predator-prey interactions are complex ecological interactions that influence community structure and function. Predators affect prey density directly by consuming and removing prey from the environment. Additionally, predators can elicit non-consumptive effects in prey which influence prey survival by altering prey behavior and physiology. Key to understanding the consequences of non-consumptive effects for prey populations is determining mechanisms of detection of predation risk. With insects, olfactory cues are commonly used to convey information. It has been shown that insect prey may eavesdrop on predator odor cues as a means to determine predation risk. Herein, we assessed whether the volatile odors of the predatory insect Harmonia axyridis (multicolored Asian lady beetle) affect the behavior (feeding and dispersal behaviors) and performance (population abundance) of aphids (Myzus persicae). Aphids reduced phloem ingestion when feeding in close proximity to lady beetle cues, however, predator odors did not drive aphids to relocate on plants or to disperse across plants away from the odor source. The lack of dispersal we observed is in contrast to studies that show increased aphid movement in the presence of predators that can make physical contact with the aphids. We also found that lady beetle odor cues had a population-level effect on aphids, with 25% reduction in aphid population abundance in the presence of the odor cues. This study highlights that anti-predator strategies may differ depending on the mechanism of detection of predation risk (i.e. olfactory versus physical stimuli), or the context in which they experience them, and raises the question of whether anti-predator responses observed are maladaptive or beneficial to aphid survival. These conclusions are critical for both our basic understanding of the mechanisms driving predator-prey interactions as well as providing insight into pest-natural enemy interactions within agricultural landscapes.