Aphis Fabae Research Articles

Can a Mixture of Farnesene Isomers Avert the Infestation of Aphids in Sugar Beet Crops?

The negative impact of pesticides on the environment and the potential of pest species to develop pesticide resistance make it necessary to explore new methods of pest control. Pheromones and other behavior-modifying semiochemicals are already important in integrated pest management (IPM). (E)-ß-farnesene (EBF) is a semiochemical that acts as an alarm pheromone in aphids. Upon perception of EBF, aphids stop feeding, move away, and sometimes even abandon the host plant. The aphids Myzus persicae and Aphis fabae are significant crop pests and vectors of many harmful phytopathogens affecting sugar beet (Beta vulgaris). Field trials were conducted at different locations in Germany to test whether dispensers containing a mixture of farnesene isomers (FIMs) including EBF were able to reduce the infestation of these species on sugar beet. Our results showed a reduction in aphid abundance in the FIM-treated patches in two out of three sites. Therefore, we hypothesize that FIM dispensers could prevent aphid infestation and could be used in combination with other IPM measures. However, more research is required to increase the effect and ensure the reliability of this method.

Progresses in lowland pulse insect pest management in Ethiopia

Grain legumes are one of the important cash crops for Ethiopian smallholder farmers and a significant agricultural commodity contributing to export earnings. Lowland pulses are comparatively inexpensive sources of protein in Ethiopia. However, these economically important crops are affected by various pests. Among the most damaging in storage are bruchids (Acanthoscelides obtectus, Zabrotes subfasciatus, and Callosobruchus spp.), while in production fields, the primary pests include the bean stem maggot (Ophiomyia spp.), African bollworm (Helicoverpa armigera), and aphids (Aphis craccivora Koch). Estimated yield losses due to bean stem maggot and African bollworm range from 11-100% and 12-16%, respectively. Various pest control strategies have been employed, including the use of resistant varieties, biological control, botanical treatments, and chemical control. This review summarizes relevant scientific studies on these economically important crops, the associated insect pests, the aggravating factors in Ethiopia, and available management options.

Influence of Weather Conditions and the Aphid Population on the Potato Virus Y Infection of Tobacco in the Field

Potato virus Y (PVY) is a major tobacco (Nicotiana tabacum L.) pathogen that causes severe crop losses. We studied the influence of meteorological factors and a population of twelve aphid species on the development of PVY in field-grown tobacco from 1996 to 2010 in Poland. Three PVY-susceptible tobacco varieties were used in the study. The mean virus incidence ranged from 18% in 2010 to almost 99% in 1996, 2004, and 2009. For determining the relationship between tobacco plant infection and meteorological conditions and aphid populations, logistic regression analysis was used. It was found that the probability of PVY infection is significantly dependent on the average air temperature, relative humidity, number of days with an average temperature of at least 25 °C, and the abundance of Aphis fabae and Brachycaudus helichrysi. The probability of infection of tobacco plants with potato virus Y decreased with increasing air temperature and relative humidity. In addition, with each subsequent day with a temperature of at least 25 °C, the risk of infection decreased by 24%. Furthermore, it was often observed that high populations of Aphis fabae and Brachycaudus helichrysi were associated with a high incidence of virus infection in tobacco plants.

Insecticidal Effect of Two Chemotypes of the Essential Oil of Eucalyptus camaldulensis Dehnh against Aphis fabae Scopoli

Background: The objective of this study was to study the insecticidal and repellent effect of the essential oil of the plant Eucalyptus camaldulensis Red Dehnh extracted by hydrodistillation method planted in the Ouargla region against the black aphid. Methods: The insecticidal effect of essential oils against aphid mortality by the introduction of bean leaflets in the different oily extracts with different concentrations and the count of dead individuals after 3, 6 and 24 h at the physiology laboratory in Ghardaïa University. Result: Through this study, the leaves treated with the major compounds of Eucalyptus camaldulensis essential oil such as Benzene,1-methyl-4-(1-methylethyl) at 35 per cent concentration after 24 hours, a 65 per cent aphid mortality was recorded which is more effective compared to Sabinene and essential oils of Eucalyptus camaldulensis at different concentrations (5; 35%; and 50 per cent). As for the repellent effect is 87 per cent after 6 hours for the pure essential oil of E. camaldulensis.

Development of bioinsecticide based on Streptomyces griseoflavus PAL114 for control of black bean aphids Aphis fabae

ABSTRACT This research highlights the efficiency of a bioinsecticide based on Streptomyces griseoflavus PAL114 in controlling black bean aphids and its effect on fava beans. Three actinobacterial strains were tested in vitro for their aphicidal activity. The PAL114 strain was then formulated in talc powder and tested again. Formulation processes were performed with four spore suspension densities (102, 104, 106 and 108 spore ml−1) at a rate of 25 ml per 100 g of talc powder. Furthermore, the in vivo effect of bioinsecticide on fava bean plants was studied in pot experiments using two application methods: spray and spray + soil amendment. The results showed that only the PAL114 strain had a highly significant effect on mortality (p = .001). Their high-density formulations at 106 and 108 spore ml−1 induced very highly significant activity (p < .001) for both, with no influence difference exceeding 90% after 58 h. In contrast, the other low-density formulations at 102 and 104 spore ml−1 had no significant effect (p = .322 and p = 1.000, respectively). There was no adverse effect of the bioinsecticide on fava bean; instead, there was an improvement in growth, especially when the spray application was combined with soil amendment. The present study opens up prospects for field studies on the biocontrol of this crop pest.

Lipopeptides from Bacillus velezensis ZLP-101 and their mode of action against bean aphids Acyrthosiphon pisum Harris

BackgroundNatural products are important sources for the discovery of new biopesticides to control the worldwide destructive pests Acyrthosiphon pisum Harris. Here, insecticidal substances were discovered and characterized from the secondary metabolites of the bio-control microorganism Bacillus velezensis strain ZLP-101, as informed by whole-genome sequencing and analysis.ResultsThe genome was annotated, revealing the presence of four potentially novel gene clusters and eight known secondary metabolite synthetic gene clusters. Crude extracts, prepared through ammonium sulfate precipitation, were used to evaluate the effects of strain ZLP-101 on Acyrthosiphon pisum Harris aphid pests via exposure experiments. The half lethal concentration (LC50) of the crude extract from strain ZLP-101 against aphids was 411.535 mg/L. Preliminary exploration of the insecticidal mechanism revealed that the crude extract affected aphids to a greater extent through gastric poisoning than through contact. Further, the extracts affected enzymatic activities, causing holes to form in internal organs along with deformation, such that normal physiological activities could not be maintained, eventually leading to death. Isolation and purification of extracellular secondary metabolites were conducted in combination with mass spectrometry analysis to further identify the insecticidal components of the crude extracts. A total of 15 insecticidal active compounds were identified including iturins, fengycins, surfactins, and spergualins. Further insecticidal experimentation revealed that surfactin, iturin, and fengycin all exhibited certain aphidicidal activities, and the three exerted synergistic lethal effects.ConclusionsThis study improved the available genomic resources for B. velezensis and serves as a foundation for comprehensive studies of the insecticidal mechanism by Bacillus velezensis ZLP-101 in addition to the active components within biological control strains.

Drought aggravates plant stress by favouring aphids and weakening indirect defense in a sugar beet tritrophic system

AbstractClimate change leads to more frequent droughts that may alter multitrophic networks in agroecosystems by changing bottom-up and top-down effects on herbivorous insects. Yet, how bottom-up effects of drought alter tritrophic interactions remains poorly understood. This study investigated two intensities of drought stress in the tritrophic system consisting of sugar beet (Beta vulgaris), an aphid (Aphis fabae), and its parasitoid (Aphidius colemani). We thoroughly investigated each trophic level, examining the performance of plants, pest insects, and parasitoids, as well as the attraction of parasitoids to herbivore-induced plant volatiles (HIPVs). Drought stress negatively affected plant growth but benefited A. fabae, leading to faster development and a higher reproduction rate. Drought-stressed plants also emitted less plant volatiles, which resulted in reduced attraction of A. colemani to aphid-infested plants. Drought indirectly affected parasitoid performance, as evidenced by lower emergence rates and production of fewer females, although mummification rates were higher on drought-stressed plants. Reduced parasitoid attraction and performance on drought-stressed plants may exert lower top-down pressure on aphid populations. Combined with increased aphid performance, this may facilitate aphid outbreaks, which could further weaken drought-stressed plants. Our findings highlight the need to study multiple trophic levels and emphasize the importance of incorporating HIPVs and parasitoid attraction when assessing combined abiotic and biotic stresses in crops.

Integrating Metarhizium anisopliae entomopathogenic fungi with border cropping reduces black bean aphids (Aphis fabae) damage and enhances yield and quality of French bean

French bean growers, rely mainly on pesticides for pest management. The acceptable tolerance for pesticides residue in French beans is a major concern and has led to several tonnes of the crop continuously rejected and listed as unsafe for human consumption. There is growing demand for alternative approaches and products that are effective at managing pests without the side-effects associated with reliance on pesticides. A field study to determine the combined effects of Metarhizium anisopliae, (Metarril WP E9 and Biomagic) biopesticides and border crops (Sunflower and wheat) on aphid population, damage severity, growth, yield and quality of French bean. A two-factor experiment was conducted at the Egerton University, Kenya. First factor included two border crops (sunflower and wheat) and no border crop (control). Second factor included spraying Metarril WPE9 (2 × 108 cfu/g), Biomagic (2 × 108 cfu/ml) biopesticides, alpha-cypermethrin (synthetic insecticide) and water. Data on growth, yield and quality parameters were collected and analyzed using the SAS version 9.4M8. Results showed that M. anisopliae and border crop significantly (p < 0.0005) enhanced growth, yield and quality of French bean in both seasons. French bean grown with wheat or sunflower borders showed a significant reduction in aphid population (p < 0.0001) and damage severity (p < 0.0001) when sprayed with various treatments compared to the control. Plots with wheat border caused an increase in collar diameter of French bean. The plots (Metarril and wheat border) caused a 4 % and 5 % increase in marketable yield, a 2 % and 12 % reduction in non-marketable yield. To exploit the benefits of biopesticides, the study recommends their integration with and border crops. Thus, French bean growers could benefit more from fungal-based biopesticides in aphid-IPM approach, as it reduces pre-harvest intervals and residues compared to synthetic insecticides.

Novel Insecticidal Butenolide-Containing Methylxanthine Derivatives: Synthesis, Crystal Structure, Biological Activity Evaluation, DFT Calculation and Molecular Docking.

The design of novel agrochemicals starting from bioactive natural products is one of the most effective ways in the discovery and development of new pesticidal agents. In this paper, a series of novel butenolide-containing methylxanthine derivatives (Ia-Ir) were designed based on natural methylxanthine caffeine and stemofoline, and the derivatized insecticide flupyradifurone of the latter. The structures of the synthesized compounds were confirmed via 1H-NMR, 13C NMR, HRMS and X-ray single crystal diffraction analyses. The biological activities of the compounds were evaluated against a variety of agricultural pests including oriental armyworm, bean aphid, diamondback moth, fall armyworm, cotton bollworm, and corn borer; the results indicated that some of them have favorable insecticidal potentials, particularly toward diamondback moth. Among others, Ic and Iq against diamondback moth possessed LC50 values of 6.187 mg ⋅ L-1 and 3.269 mg ⋅ L-1, respectively, - 2.5- and 4.8-fold of relative insecticidal activity respectively to that of flupyradifurone (LC50=15.743 mg ⋅ L-1). Additionally, both the DFT theoretical calculation and molecular docking with acetylcholine binding protein were conducted for the highly bioactive compound (Ic). Ic and Iq derived from the integration of caffeine (natural methylxanthine) and butenolide motifs can serve as novel leading insecticidal compounds for further optimization.

Efficacy of Extracts of Bishop's Flower &lt;i&gt;Ammi majus&lt;/i&gt; against Black Bean Aphid &lt;i&gt;Aphis fabae&lt;/i&gt; Scopoli

Experiments were performed in the laboratory of the Biological Control Department at the Al-Mussaib Technical College during February-July, 2023 for evaluating the efficacy of crude aqueous and alcoholic extracts of flowers and leaves of Bishop’s flower Ammi majus against the black bean aphid, Aphis fabae Scopoli, results revealed that the hot water extract proved superior to cold water extract and hot water extract of flowers was superior compared to leaf extract with mortality of 29.7% nymphs and adults 19.6% respectively.

Circadian pattern in attendance of aphid colonies by ants

Ant-attendance of aphids is one of the subjects of interest in ecological studies as a reciprocal service providing benefits to both groups involved. The behavioural patterns in this relation depend on many factors, e.g. biology of the species involved, aphid host plants, activity of natural enemies and abiotic factors. In this respect, the circadian pattern of ant-attendance was almost unknown. The paper presents the results of the pattern of such circadian activity of ants Lasius niger and L. emarginatus attending six aphid species (Panaphis juglandis, Aphis grossulariae, A. urticata, A. umbrella, Myzus persicae and Aphis fabae) feeding on various types of plants and having various dependence of trophobiosis. The highest number of ant workers in aphid colonies was observed at night and dawn, while the lowest was just after solar noon. The circadian pattern of ant activity strongly depends on the weather, especially temperature and relative humidity, with the highest abundance of ants during humid and cool weather. The possible interconnection between the temperature-dependent activity of ants and the water-dependent physiological condition of certain plants is discussed and indicated as an explanation. The issue of possible work division among ant workers attending aphids as an explanation of the observed pattern of activity remains open.

Temporal Analysis of the Relationship between Black Bean Aphid (Aphis fabae) Infestation and Meteorological Conditions in Faba Bean (Vicia faba)

Temporal Analysis of the Relationship between Black Bean Aphid (Aphis fabae) Infestation and Meteorological Conditions in Faba Bean (Vicia faba)

Transcriptomic Profiling of Bean Aphid Megoura crassicauda upon Exposure to the Aphid-Obligate Entomopathogen Conidiobolus obscurus (Entomophthoromycotina) and Screening of CytCo-Binding Aphid Proteins through a Pull-Down Assay.

Prolonged periods of host-lethal infection by entomopathogenic fungi pose challenges to the development of biological control agents. The obligate entomopathogen C. obscurus, however, rapidly kills aphid hosts, warranting investigation. This study investigated the interaction between C. obscurus and a bean aphid Megoura crassicauda during the incubation period of infection, using transcriptome analysis to map host gene expression profiles. Results indicate C. obscurus-inoculated aphid activation of the wound healing immune responses, alongside suppression of the key molecules involved in Toll signaling, melanization, and metabolism. Furthermore, neuromotor system-related genes were upregulated, paralleling the intoxication observed in a nematode pest treated with C. obscurus-derived CytCo protein. To deepen interaction insights, a His-tag pull-down assay coupled with mass spectrometry analysis was conducted using CytCo as a bait to screen for potential aphid protein interactors. The proteins were identified based on the assembled transcriptome, and eleven transmembrane proteins were predicted to bind to CytCo. Notably, a protein of putatively calcium-transporting ATPase stood out with the highest confidence. This suggests that CytCo plays a vital role in C. obscurus killing aphid hosts, implicating calcium imbalance. In conclusion, C. obscurus effectively inhibits aphid immunity and exhibits neurotoxic potential, expediting the infection process. This finding facilitates our understanding of the complex host-pathogen interactions and opens new avenues for exploring biological pest management strategies in agroforestry.

Ecological divergence despite common mating sites: Genotypes and symbiotypes shed light on cryptic diversity in the black bean aphid species complex.

Different host plants represent ecologically dissimilar environments for phytophagous insects. The resulting divergent selection can promote the evolution of specialized host races, provided that gene flow is reduced between populations feeding on different plants. In black bean aphids belonging to the Aphis fabae complex, several morphologically cryptic taxa have been described based on their distinct host plant preferences. However, host choice and mate choice are largely decoupled in these insects: they are host-alternating and migrate between specific summer host plants and shared winter hosts, with mating occurring on the shared hosts. This provides a yearly opportunity for gene flow among aphids using different summer hosts, and raises the question if and to what extent the ecologically defined taxa are reproductively isolated. Here, we analyzed a geographically and temporally structured dataset of microsatellite genotypes from A. fabae that were mostly collected from their main winter host Euonymus europaeus, and additionally from another winter host and fourteen summer hosts. The data reveals multiple, strongly differentiated genetic clusters, which differ in their association with different summer and winter hosts. The clusters also differ in the frequency of infection with two heritable, facultative endosymbionts, separately hinting at reproductive isolation and divergent ecological selection. Furthermore, we found evidence for occasional hybridization among genetic clusters, with putative hybrids collected more frequently in spring than in autumn. This suggests that similar to host races in other phytophagous insects, both prezygotic and postzygotic barriers including selection against hybrids maintain genetic differentiation among A. fabae taxa, despite a common mating habitat.

Efficacy of the entomopathogenic fungus Metarhizium anisopliae (Clavicipitaceae: Hypocreales) against the black bean aphid (Aphis fabae Scopoli, 1763) under laboratory conditions

Black bean aphid (BBA) is a serious insect pest that severely significantly impacts French bean production. Over-reliance on synthetic chemicals to reduce economic losses caused by aphids poses serious environmental and human health threats. Biopesticides containing entomopathogenic fungi (EPF) have potential as viable alternatives that can be incorporated into integrated to manage such insect pests. The efficacy of Metarhizium anisopliae against BBA was assessed in the laboratory under a complete randomized design (CRD) design with five replicates. Data was analysed using SAS 9.4 (2021). In part one, Metarhizium anisopliae products caused bean aphid mortality etween 60.1% and 95.5%. Mazao supreme (4×108 spores/ml) and Metarril (4×108 spores/ml) caused the highest mortality (95.5%) and the lowest concentration of irrespective product caused the lowest mortality (60.1%) after treatment application. In part two, alpha-cypermethrin caused the highest aphid mortality (99.3%), followed by Metarril (84.2%), Mazao (80.7%) and biomagic had the lowest (68.4%) mortality after treatment application. Alpha-cypermethrin had the lowest lethatl time (LT50), causing 50% aphid mortality, followed by Metarril, Mazao supreme, and biomagic. Differents treatments had varying effects on nymph numbers. Alpha-cypermethrin caused 50% aphid mortality, followed by Metarril, Mazao supreme, and biomagic, with varying effects on nymph numbers. The study recommends incorporating Metarhizium anisopliae-based biopesticides, particularly Metarril by small holder farmers to offer a cost-effective integrated pest management approach for managing BBA (adults and nymphs) in French bean production while reducing reliance on synthetic chemicals. Keywords: Black bean aphid, biopesticides, French beans

Potential of Thuja occidentalis L. Essential Oil and Water Extracts against Field Crop Pests.

Thuja occidentalis L. essential oil (EOTO) and its compounds, such as terpinyl acetate, bornyl acetate, and β-thujone, are claimed to be highly effective against some storage pests, sanitary insects, or pests of fruit trees, while data about its use in protecting field crops are very scarce. There is also a lack of information in the literature about the insecticidal value of water extracts from T. occidentalis (WETOs). Both essential oils (EOs) and water extracts (WEs) from various plants have advantages and disadvantages in terms of their use as insecticides. EOs are generally more effective, but their preparation is more complicated and quite expensive. In turn, WEs are simple to prepare and cheap, but they often have limited effectiveness. Moreover, significant differences in responses exist depending on the species of the donor plant, the method of preparing the extract, its concentration, the species of the pest being controlled, the developmental stage, and even the gender of the pest. The goals of the research were to assess the effect of EOTO and WETOs prepared from dry and fresh matter on the mortality, feeding, and body mass changes of important crop pests, i.e., the black bean aphid, pea leaf weevil, and Colorado potato beetle (CPB), respectively, as well as on the mortality and voracity of non-target organism Asian lady beetle young larvae. EOTO showed significant aphicidal activity with LC50 = 0.8267% and 0.2453% after 42 h of the experiment for nymphs and wingless females of black bean aphid, respectively. Adults of CPB were more resistant to EOTO than aphids, with LC50 values for females equal to 1.5327% and 1.3113% after 48 h and after 72 h of the experiment. There was no significant effect of EOTO on CPB foraging. Calculated LC50 values for pea leaf weevil adults were lower than those for CPB (0.9638% and 0.8573% for males after 12 h and 24 h, respectively). In the case of this pest, a clear reduction in foraging was obtained, with higher concentrations of EOTO resulting in more pronounced reductions in foraging behavior. Concentrations of EOTO above 0.5%, which showed efficacy against the aphid, were lethal to 3-day-old larvae of the Asian lady beetle. WETOs, in turn, showed significant potential in inhibiting adult pea leaf weevil feeding, with very low or no effectiveness in reducing A. fabae and CPB, respectively.

Parasitoid species diversity has no effect on protective symbiont diversity in experimental host-parasitoid populations.

How does diversity in nature come about? One factor contributing to this diversity are species interactions; diversity on one trophic level can shape diversity on lower or higher trophic levels. For example, parasite diversity enhances host immune diversity. Insect protective symbionts mediate host resistance and are, therefore, also engaged in reciprocal selection with their host's parasites. Here, we applied experimental evolution in a well-known symbiont-aphid-parasitoid system to study whether parasitoid diversity contributes to maintaining symbiont genetic diversity. We used caged populations of black bean aphids (Aphis fabae), containing uninfected individuals and individuals infected with different strains of the bacterial endosymbiont Hamiltonella defensa, which protects aphids against parasitoids. Over multiple generations, these populations were exposed to three different species of parasitoid wasps (Aphidius colemani, Binodoxys acalephae or Lysiphlebus fabarum), simultaneous or sequential mixtures of these species or no wasps. Surprisingly, we observed little selection for H. defensa in most treatments, even when it clearly provided protection against a fatal parasitoid infection. This seemed to be caused by high induced costs of resistance: aphids surviving parasitoid attacks suffered an extreme reduction in fitness. In marked contrast to previous studies looking at the effect of different genotypes of a single parasitoid species, we found little evidence for a diversifying effect of multiple parasitoid species on symbiont diversity in hosts.

In vitro Screening of Natural Metarhizium spp. Isolates for Bioinsecticidal and Biofungicidal Activity

Aims: To increase conidia production of local Metarhizium spp—strains by selecting the low-cost media to test obtained bioformulation against the sucking pests and fungal plant pathogens. Study Design: The phytophages like black bean aphid (Aphis fabae), a scale insect (Aspidiotus nerii) and spider mite (Tetranychus urticae) are economically essential pests in Kyrgyzstan. The current requirement is to use environmentally friendly protection to reduce the number of these pests. The entomopathogenic fungus from the Metarhizium genus was used to reduce harmful pests in vitro and in vivo experiments. Place and Duration of Study: Department of Plant Protection, Kyrgyz-Turkish Manas University between May 2021 and May 2023. Methodology: Natural Metarhizium spp. strains were isolated from dead insect bodies of the Lepidoptera and Apidae families. A laboratory bioassay was conducted to evaluate isolated Metarhizium spp.strains against nymphal stages and adults of sucking pests like A. fabae ((Blackfly), A.nerii (Scale insect) and T.urticae (Spider mite). The inhibitory effect of Metarhizium spp.against Fusarium oxysporum, Alternaria spp. and Rhizoctonia solani was detected using a dual culture technique. Results: The results of in vitro bioassay tests against sucking pests have revealed the LC50 and LT50 values of TLK-1 isolate. The LC50 of this isolate for A. fabae adults was 1 × 106 conidia\ mL-1; for A.nerii, it was lower - 7 × 105 conidia\ ml-1; while for adults T.urticae it was higher- 13 × 106 conidia \ ml-1. Such mortality occurred after 49.63 hours in adults of A. fabae (LT50), after 46.30 hours in A.nerii (LT50), and after 75.87 hours in deutonymph and adults of T. urticae (LT50). Three isolates, TLK-1, TLA-2 and BZТК1, have exhibited biofingicide activity in pathogen fungi like Fusarium oxysporum and Alternaria spp. Conclusion: The found isolates can be simultaneously used against pathogenic fungi, essential for developing inexpensive biological formulas based on these fungi.

Quinolizidine Alkaloids and Isoflavones from the Herb of Thermopsis lupinoides and Their Antiviral, Antifungal, and Insecticidal Activities.

As part of our ongoing investigation of natural bioactive substances from the genus Thermopsis of the tribe Fabaceae for agricultural protection, the chemical constituents of the herb Thermopsis lupinoides were systematically investigated, which led to the isolation of 39 quinolizidine alkaloids (QAs) (1-39), including 14 new QAs (1-14) and 14 isoflavones (40-53). Their structures were elucidated through comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS), ECD calculations, and X-ray crystallography. The antitomato spotted wilt virus (TSWV) and antifungal (against Botrytis cinerea, Gibberella zeae, Phytophythora capsica, and Alternaria alternata) and insecticidal (against Aphis fabae and Tetranychus urticae) activities of the isolated compounds were screened using the lesion counting method, mycelial inhibition assay, and spray method, respectively. The bioassay results showed that 34 exhibited excellent protective activity against TSWV, with an EC50 value of 36.04 μg/mL, which was better than that of the positive control, ningnanmycin (86.03 μg/mL). The preliminary mechanistic exploration illustrated that 34 induced systemic acquired resistance in the host plant by acting on the salicylic acid signaling pathway. Moreover, 1 showed significant antifungal activity against B. cinerea (EC50 value of 20.83 μg/mL), while 2 exhibited good insecticidal activity against A. fabae (LC50 value of 24.97 μg/mL). This research is promising for the invention of novel pesticides from QAs with high efficiency and satisfactory ecological compatibility.

Exploring horizontal transfer of mariner transposable elements among ants and aphids

Aphids and ants are mutualistic species with a close space-time relationship, which may facilitate the occurrence of horizontal transfer events between these insect groups. Myrmar-like mariner elements were previously isolated from two ant (Myrmica ruginodis and Tapinoma ibericum) and two aphid species (Aphis fabae and Aphis hederae). The aim of this work is to determine the presence of Myrmar-like mariner elements in new ant and aphid species, as well as to analyze the likelihood of horizontal transfer events between these taxa. To accomplish this, the Myrmar-like element has been isolated from five aphid species and six ant species. Among these new analyzed species, full-length Myrmar-like mariner elements with very high sequence similarity have been isolated from the aphids Aphis nerii, Aphis spiraecola, Brachycaudus cardui, and Rhopalosiphum maidis as well as from the ants Lasius grandis and Lasius niger, even though aphids and ants belong to two insect orders (Hemiptera and Hymenoptera) that have evolved independently for at least 300 million-years. Both Lasius species establish frequent mutualistic relationships with multiple aphid species, including A. nerii, A. spiraecola, and B. cardui. The study of the putative protein encoded by them and the phylogenetic analysis suggests that they could be active transposons shared by aphids and ants through horizontal transfer events. Additionally, mariner elements with internal deletion were found in several aphids and one ant species, showing a high degree of sequence similarity among them. The characteristics of these elements with internal deletion suggest a complex origin involving various evolutionary processes, possibly including also horizontal transfer events. Myrmar-like elements have also been isolated from the other ant species, although without similarity with the aphid mariner sequences. Myrmar-like elements are also present in phylogenetically distant insect species, as well as in one crustacean species. The phylogenetic study carried out with all Myrmar-like elements suggests the probable occurrence of horizontal transfer events.