Molecular biology of Cotton Leafroll Dwarf Virus (CLRDV) and potential application of CRISPR-Cas technology for developing virus-resistant cotton.

ABSTRACTA study conducted in Egypt evaluated the effectiveness of chemical and microbial agents in enhancing sweet pepper (Capsicum annuum var. annuum) defenses against major pests Aphis gossypii and Thrips tabaci and their natural predators, Chrysoperla carnea and Orius insidiosus. Five foliar treatments were tested under greenhouse conditions during the 2022 and 2023 growing seasons: salicylic acid (SA), potassium phosphite (PK), effective microorganisms (EMs), insecticide imidacloprid (IMI), and a water‐sprayed untreated check (control). In addition to monitoring pest and predator populations, several biochemical parameters were assessed in pepper leaves, including total chlorophyll, macronutrients (N, P, K), phenolic compounds, and total protein content. All treatments improved plant growth and enhanced physiological traits, promoting both vegetative development and fruit productivity. Salicylic acid was the most effective treatment, significantly increasing chlorophyll levels, nutrient uptake, phenolic content, and total proteins. Moreover, all agents led to a marked reduction in pest populations while preserving predator abundance, indicating strong plant defense activation and selectivity toward beneficial insects. These findings demonstrate that the tested agents, particularly salicylic acid, can serve as practical and sustainable alternatives to synthetic insecticides and are suitable for integration into environmentally friendly pest management strategies and Integrated Pest Management (IPM) programs.

The cotton aphid (Aphis gossypii) is a major pest of greenhouse peppers in southern Spain. Biological control using the parasitoid wasp Aphidius colemani is limited because the ant Tapinoma ibericum, engaged in a mutualistic relationship with aphids, protects them from parasitoid attack and thereby reduces parasitism success. To assess the impact of ants on pest biological control, an ant-exclusion experiment was conducted over two consecutive years in four experimental greenhouses. Pepper plants were infested with aphids and then treated with Aphidius colemani. The presence of natural enemies and fruit production were also evaluated. Excluding ants significantly increased the abundance of mummies by 22.2% and reduced the number of aphid colonies, while total aphid abundance showed variable, year-dependent effects and was not affected by ants. Ant presence negatively affected some natural enemies such as Chrysoperla carnea s.l., the mirid Nesidiocoris tenuis, and the ladybird Scymnus sp., had no effect on hoverflies and spiders, and increased the abundance of Aphidoletes aphidimyza, indicating contrasting responses among natural enemies. Fruit weight was not affected by ant presence. Overall, these findings confirm that T. ibericum reduces parasitism by A. colemani, and demonstrate that it modifies aphid spatial distribution, and reshapes the natural enemy community, but does not necessarily diminish crop production. These results suggest that combining A. aphidimyza with A. colemani could improve control of A. gossypii in ant-infested crops.

Over-reliance on and excessive use of pesticides for pest management have led to various side effects, including the rapid development of pesticide resistance. The abundant reactive species present in plasma-activated water (PAW) make it a potential alternative to pesticides for controlling crop pests. Whether PAW can truly replace pesticides or significantly reduce their usage depends on its efficacy when applied in the same manner as pesticides. A foliar spray bioassay that simulates the field application of pesticides was established to estimate the direct toxicity of PAW to two insecticide-susceptible and two resistant strains of cotton aphids in the presence and absence of imidacloprid or flonicamid. Spraying PAW alone only caused mortality of about 20-30% against the four cotton aphid strains, significantly lower than the effects of imidacloprid LC25 dose and flonicamid LC25 dose to the four strains. Spraying a mixture of PAW and imidacloprid at LC25 dose or flonicamid at LC25 dose resulted in significantly higher mortality rates against the four strains compared to the two insecticides diluted with pure water. Relative to pure water control, PAW and its mixtures with imidacloprid LC25 dose or flonicamid LC25 dose displayed no adverse effects on chlorophyll content and the photosynthetic parameters of cotton seedlings. The data obtained indicate that PAW has the potential to serve as a plant-safe synergist for enhancing the insecticidal efficacy of imidacloprid and flonicamid against both insecticide-susceptible and -resistant cotton aphids. © 2026 Society of Chemical Industry.

Plants have evolved intricate defense strategies to combat herbivorous insect attacks, including the production of toxic secondary metabolites and the attraction of natural enemies. While bacterial-mediated direct toxicity in plant defenses has been demonstrated, the ecological mechanisms by which plants utilize bacteria to indirectly modulate the behavior of natural enemies remain insufficiently explored. In this study, we observed a significant enrichment of Staphylococcus in the tissues of zucchini Cucurbita pepo following infestation by the cotton-melon aphid Aphis gossypii. These bacteria traced from the damaged plant stems and leaves were subsequently found both in aphids and in their secreted honeydew. Among the four dominant bacterial strains isolated from the honeydew, Staphylococcus sp. markedly promoted oviposition preference in mated female ladybird beetles Propylea japonica. Further investigation identified a volatile organic compound, 4-Isopropylbenzyl alcohol, released by Staphylococcus sp. that stimulated strong antennal responses and attracted P. japonica to lay eggs. Collectively, our findings demonstrate that zucchini plants can employ indirect defense against A. gossypii through the enrichment of specific bacteria, revealing a novel ecological role for bacteria in plant defense and expanding our understanding of complex plant-microbe-insect-natural enemy interactions.

The cotton aphid (Aphis gossypii) is a major pest detrimental to cotton production, and the development of control strategies has been a key research focus. NBS-LRR-type disease resistance genes, the predominant class of R genes, have been found to confer dual resistance against aphids. This study identified 88 resistance to aphid protein (RAP) genes in Gossypium hirsutum (G. hirsutum), other cotton species, and Arabidopsis thaliana (A. thaliana), with a focus on G. hirsutum resistance to aphid protein (GhRAP1). Its expression was upregulated following aphid infestation. Functional analysis demonstrated that silencing GhRAP1 in cotton rendered plants more susceptible to aphid infestation, while its overexpression in A. thaliana effectively deterred aphid feeding and reduced their survival and reproductive rates. Electrical penetration graph (EPG) results further revealed that GhRAP1-overexpressing plants enhanced the mechanical resistance against aphid penetration and significantly shortened the duration of phloem feeding. These findings collectively indicate that GhRAP1 confers plant resistance through both antixenosis and antibiosis mechanisms, providing crucial insights for developing novel aphid control strategies.

As a polyphagous agricultural pest of global significance, Aphis gossypii exhibits substantial population differentiation and inflicts damage across a broad host range, including economically important leguminous crops. This study aimed to clarify the adaptation of three A. gossypii haplotypes (Hap1, Hap3, Hap4) to four legume hosts: cowpea (Vigna unguiculata) varieties Zhongshouluchangfeng (ZLC) and Zhongshoucuichangfeng (ZCC), hyacinth bean (Lablab purpureus) and winged bean (Psophocarpus tetragonolobus). Results showed Hap1 and Hap4 on cowpeas had higher net reproductive rate (R0 > 25) and intrinsic rate of increase (r > 0.36) than on hyacinth bean and winged bean (R0 < 6, r < 0.27). Meanwhile, Hap3 exhibited poor life-table parameters on all legumes. Among legumes, all haplotypes preferred hyacinth bean and refused to feed on winged bean. EPG analysis showed that Hap1 and Hap4 had longer nonprobing time on winged bean, and prolonged xylem ingestion on hyacinth bean. All haplotypes fed longer on cowpea phloem than on hyacinth bean and winged bean. Notably, the proportion of saliva secretion time in the phloem feeding duration of A. gossypii feeding on winged bean exceeded 75%. A. gossypii that fed on cowpeas secreted the highest amount of honeydew CONCLUSION: Different haplotypes of cotton aphids show differentiated adaptability to legumes, and there also is differentiation in the aphid resistance among legumes. These findings can be applied to the formulation of aphid control technologies for legumes and lay a foundation for studying the co-evolution between A. gossypii and their hosts. © 2025 Society of Chemical Industry.

Laboratory selection, resistance risk assessment, fitness costs and biochemical mechanism of Aphis gossypii to flonicamid.

To explore alternative methods for insect control, we investigated the effectiveness of natural biostimulants in triggering defense responses against the cotton-melon aphid Aphis gossypii on tomato plants. The tested biostimulants were rosemary essential oil, the fungus Trichoderma harzianum, the PGPR (Plant Growth-Promoting Rhizobacteria) Bacillus subtilis, and a mix of microalgae. Their effects were compared to an untreated control and to the chemical product Bion (a salicylic acid pathway inducer) as a positive control. Tomato seedlings were exposed to aphid infestation at different leaf levels, and aphid colony development was monitored over time. The impact of biostimulants was assessed by counting aphid numbers at 72 h post-infestation. Additionally, aphid fecundity was evaluated in a subsequent trial with potted tomatoes. In parallel, we explored the rapid effects of root-fed biostimulants on aphid populations using hydroponic tomato seedlings. Leaves from plants treated with biostimulants and with the reference product Bion showed a significant reduction in adult aphid population density and reproduction rates compared to untreated controls. Specifically, control plants exhibited higher aphid reproduction rates, which was significantly reduced at 6 days post-infestation. However, no significant differences were observed between treated and control plants beyond this time, indicating that a strong plant defense response was triggered within one week. Our findings clearly demonstrate the great potential of using biostimulants as promising tools for enhancing tomato integrated pest management.

Aphis gossypii Glover (Hemiptera: Aphididae) poses a major threat to okra cultivation, causing significant yield losses worldwide. This study evaluated the efficacy of the entomopathogenic fungus Lecanicillium fusisporum strain NBAIR-Vl8 against A. gossypii in both laboratory and field environments, along with Metarhizium anisopliae NBAIR-Ma4 and Beauveria bassiana NBAIR-Bb5a. L. fusisporum NBAIR-Vl8 exhibited high virulence, with an LC₅₀ of 4.22 × 10⁴ spores/mL and LT₅₀ and LT₉₀ values of 60.45 h and 86.97 h, respectively. Over 2 years of field trials, there were significant reductions in aphid (73.65%) and leafhopper, Amrasca biguttula biguttula (67.93%) populations and increased yield (6.64 q ha- 1) compared to untreated plots (3.98 q ha- 1). LC-MS/MS and GC-MS analyses of NBAIR-Vl8 identified important bioactive metabolites, including penitrem D, zwittermicin A, β-sitosterol, curcumin, and (1 R,2S)-naphthalene 1,2-oxide. To explore potential molecular targets, homology models of A. gossypii nicotinic acetylcholine receptor (nAChR) and chemosensory protein CSP8, as well as A. biguttula biguttula ribosomal protein L13 and tubulin beta chain, were developed and validated. Molecular docking using AutoDock Vina revealed that penitrem D had the highest binding affinities (-8.9 kcal/mol for nAChR), surpassing the commercial insecticide thiamethoxam (-5.4 kcal/mol for nAChR). β-sitosterol and curcumin also demonstrated strong interactions with CSP8 and structural proteins. These targets are essential for neurotransmission, olfaction, protein synthesis, and cytoskeletal integrity, indicating a multitarget mechanism of action of the drug. NBAIR-Vl8 shows significant biocontrol potential, supported by in vitro, field, and in silico evidence, highlighting its potential as a broad-spectrum microbial pesticide for integrated pest management.

Red chili pepper (Capsicum annuum) is a high-value horticultural crop in Indonesia, but its production is severely constrained by Aphis gossypii, which can cause yield losses of up to 65%. This study aimed to evaluate the biological characteristics, virulence, and lethal-sublethal effects of local isolates of Beauveria bassiana and Metarhizium anisopliae against A. gossypii. Fungal viability and growth were assessed through spore germination and radial growth assays, while pathogenicity was evaluated using four conidial concentrations (10⁴–10¹⁰ conidia mL⁻¹). Aphid mortality, lethal concentration (LC), lethal time (LT), and reproductive performance were recorded, and the data were analyzed using factorial and probit analyses. The results showed that both fungi exhibited high spore viability (&gt;96%) and stable mycelial growth rates (3.71–3.74 mm day⁻¹). Aphid mortality increased significantly with increasing conidial concentration, reaching 100% at 10¹⁰ conidia mL⁻¹, whereas mortality at 10⁴ conidia mL⁻¹ ranged from 26.67% to 40.00%. Probit analysis revealed comparable virulence, with LC₉₅ values of 8.09 for M. anisopliae and 8.29 for B. bassiana. Lethal time analysis showed a concentration-dependent killing pattern, with B. bassiana acting more rapidly at lower concentrations (10⁴–10⁶ conidia mL⁻¹) and M. anisopliae exhibiting shorter LT₅₀ values at higher concentrations (10⁸–10¹⁰ conidia mL⁻¹). In addition to lethal effects, both fungi significantly suppressed aphid reproduction, particularly at higher conidial concentrations. These findings demonstrate that B. bassiana and M. anisopliae possess strong and complementary bioefficacy against A. gossypii, supporting their potential application in integrated pest management programs.

Chinese wolfberry (Lycium barbarum L.), a specialty crop with ecological, medical, and economic value in Ningxia province of China, is subject to severe damage from Aphis gossypii Glover. Currently, A. gossypii populations show extremely high-level resistance to beta-cypermethrin in the major wolfberry planting areas in Ningxia. The specific resistance mechanisms, however, are still not known. In this work, we collected a field A. gossypii strain (HSP) from a wolfberry orchard in Ningxia in 2021 using a single-time sampling method, and its resistance to beta-cypermethrin was determined to be extremely high (994.74-fold) as compared with that of a susceptible strain (SS). Then we explored the potential resistance mechanisms from two aspects, namely, metabolic detoxification and target-site alterations. Bioassays of beta-cypermethrin with or without a synergist showed that piperonyl butoxide (PBO) significantly increased the toxicity of beta-cypermethrin (4.72-fold) to the HSP strain, while triphenyl phosphate (TPP) and diethyl maleate (DEM) exhibited no significant synergistic effects. Correspondingly, the O-demethylase activity of cytochrome P450s in the HSP strain was 1.68-fold higher than that in the susceptive strain (SS), whereas changes in carboxylesterases and glutathione S-transferases activities were unremarkable. Also, fifteen upregulated P450 genes were identified by both RNA-Seq and qRT-PCR technologies, containing eleven CYP6 genes, three CYP4 genes, and one CYP380 gene. Especially, five CYP6 genes with high relative expression levels (&gt;3.00-fold) were intensively expressed by beta-cypermethrin induction in the HSP aphids. These metabolism-related results indicate the key role of P450-mediated metabolic detoxification in HSP resistance to beta-cypermethrin. Sequencing of voltage-gated sodium channel (VGSC) genes identified a prevalent M918L mutation and a new G1012D mutation in HSP A. gossypii. Moreover, heterozygous 918 M/L and 918 M/L + G1012D mutations were the dominant genotypes with frequencies of 60.00% and 36.67% in the HSP population, respectively. Overall, VGSC mutations along with P450-mediated metabolic resistance contributed to the extremely high resistance of the HSP wolfberry aphids to beta-cypermethrin, providing support for A. gossypii control and resistance management in the wolfberry planting areas of Ningxia using insecticides with different modes of action.

Efficiency of Treating Cucumber Plants by Titanium Nanoparticles (TiO2) on the Infestation by Aphis gossypii under Greenhouses

A field study entitled “Impact of weather parameters on the population pattern of sucking insect pests okra in Tandojam” was carried out at the experimental area of Horticulture Section, Tandojam during 2019, to investigate the seasonal population of sucking insects with the relation to the ecological components at Tandojam surroundings. The Sabzpari variety was sown on second week of February and results indicats that the sucking insect species such as Bemisia tabaci, Thrips tabaci, Aphis gossypii and A. bigutella bigutalla were appered on okra crop just three weeks after sowing till June and peaks of the population of insects were observed in the month of April.Further data of overall seasonal average population of sucking insect complex on okra were revealed that the average number of whitefly was (15.87±2.45), Jassid (21.50±3.50), Thrip (14.50±2.56) and Aphid (13.45±2.78) were recorded on okra crop during cropping season, respectively. Further enviormental factors play important role on insect reproduction, population build up and other life activities. As result showed that ecological parameters had positive and negative impact on sucking insect pest population on okra crop. However, temperature showed significant positiove with whitefly (r= 0.67*), and highly positive with Jassid (r= 0.89**), with thrip (r= 0.55*) and with aphid (r= 0.49*), respectively at (P &lt;0.05* and P &lt; 0.01**). Furthermore, relative humidity showed negative correlation such as, with whitfly (-r= 0.55*), with Jassid (-r= 033**), with thrip (-r= 0.61*) and with aphid (-r= 063*), respectively at statistically leveal (P &lt;0.05* and P &lt; 0.01**), respectively.

Cucumber mosaic virus (CMV) is widely recognized as a damaging pathogen in cucurbits and numerous other horticultural crops. It has an unusually broad host range, with the ability to infect more than 1,000 plant species, and it can also persist in common weed populations, which facilitates its rapid dissemination within cropping systems. Among the many insects that can carry the virus, the aphid Aphis gossypii is generally regarded as the most efficient at transmitting it. Because of these factors, growers frequently report management challenges due to the virus’s broad host range and efficient vector transmission. Plants affected by CMV may show a mixture of symptoms including mosaic mottling, leaf distortion, yellowing, reduced growth, and malformed plant structures. Collectively, these symptoms contribute to reduced plant vigor, diminished yields, and poor-quality marketable produce. Research at the molecular level has shown that much of the virus’s ability to damage plants is linked to components such as the CMV 2b protein, which interferes with RNA-silencing processes and disrupts hormonal regulation, promoting enhanced viral accumulation within host tissues. Several types of laboratory tests are commonly employed to confirm the presence of CMV. ELISA and similar serological assays are still widely used, while molecular techniques such as RT-PCR and LAMP offer higher sensitivity. High-throughput sequencing is becoming increasingly accessible for early detection and strain differentiation. Farmers rarely depend on a single tactic to manage CMV. They integrate crop rotation, hygiene, and vector control. Novel molecular tools such as CRISPR-based genome editing and RNA interference are being explored to enhance detection and resistance strategies, and plant breeders are actively developing CMV-resistant cultivars. While these emerging approaches show promise, long-term field validation is still required. CMV infection increases management costs due to additional monitoring and control inputs. Reducing CMV-related losses requires continued research on virus-host interactions, resistant variety development, and integrated management. Keywords: Cucumber mosaic virus; Cucurbitaceae; aphid transmission; diagnostics; epidemiology; CMV 2b protein; satRNAs; integrated disease management.

Chemical composition and aphicidal activity of Santolina africana essential oil: a new opportunity in Aphis gossypii management?

Melon (Cucumis melo L.) is one of the high-value horticultural commodities with continuously increasing market demand. However, its productivity is often hindered by major pest attacks such as aphids (Aphis gossypii), fruit flies (Bactrocera spp.), and armyworms (Spodoptera sp.). This study aims to analyze the effect of the frequency of insecticide application containing the active ingredient deltamethrin on pest attack intensity and melon plant growth parameters, pest classification. The study was conducted at UG Techno Park, Cianjur, from February to June 2025 using a nested completely randomized block design (CRBD) with the Inthanon and Madesta varieties. The treatments included insecticide application every 7 days, every 14 days, and no application (control). The results showed that insecticide application every 7 days reduced pest attack intensity to 12.25%. The Madesta variety performed best with a pest attack intensity of 11.04% and fresh harvest weight reaching 1.743.75 grams per plot. The combination of insecticide application strategies and CNN-based classification has proven effective in improving pest identification accuracy and supporting precise and sustainable pest control.

Abstract Herbivory can affect the soil microbiome, creating legacies that affect plant resistance, but how these effects vary by feeding guild and the plant traits involved remain underexplored. We tested how soil legacies created by a leaf‐chewing caterpillar ( Spodoptera exigua ) and a sap‐feeding aphid ( Aphis gossypii ) influence resistance in Baccharis salicifolia by evaluating changes in plant traits and soil microbial diversity. We conditioned soil with three herbivory treatments on B. salicifolia : caterpillar herbivory, aphid herbivory or control (no herbivory). Then, we grew new plants in sterile soil inoculated with 10% conditioned soil from each treatment and conducted resistance bioassays, measured plant nutritional and defence traits and analysed microbial diversity. Caterpillar, but not aphid herbivory, created legacies that affected resistance to both herbivores in opposite directions: plants in caterpillar‐conditioned soil had 16% smaller aphid colonies than plants in control soil, and a 76% increase in caterpillar performance relative to aphid‐conditioned soil, suggesting guild‐specific trade‐offs in resistance. These plants also showed a 12% higher carbon‐to‐nitrogen ratio than plants in control soil, mediating resistance to the aphid but not to the caterpillar. Herbivory did not affect microbial taxonomic diversity, suggesting shifts in microbiome biomass or function underlie the observed effects. Our findings highlight that herbivory‐induced soil legacies are guild‐specific and can alter plant resistance via trait‐mediated pathways, underscoring the importance of considering herbivore identity when evaluating above–below‐ground feedbacks. Read the free Plain Language Summary for this article on the Journal blog.

Abstract Cotton aphid ( Aphis gossypii Glover) severely impacts cotton yield and quality, necessitating effective detection and control measures. Traditional manual detection methods are inefficient, highlighting the need for rapid and accurate detection. In order to realize rapid and accurate cotton aphid detection, we proposed a novel attention mechanism named Bi-Enhanced Attention Mechanism (BEAM), aiming at improving the performance of the YOLOv8-s model. Furthermore, we employed a domain-adaptive transfer learning strategy by pre-training our enhanced network model on a public forestry pest dataset and fine-tuning it on a custom-built cotton aphid dataset. In this study, we evaluate our approach using the mean Average Precision (mAP) at different Intersection over Union (IoU) thresholds. Experimental results demonstrated that our approach achieved excellent performance in detecting cotton aphids. Specifically, our approach, which includes an enhanced YOLOv8-s model with a bi-enhanced attention mechanism and a domain adaptive transfer learning strategy, achieved an mAP of 58.1% at an IoU threshold range of 0.5 to 0.95 (mAP@0.5:0.95), 95.4% at an IoU threshold of 0.5 (mAP@0.5), and 64.8% at an IoU threshold of 0.75 (mAP@0.75). Compared to the baseline method, which utilizes the original YOLOv8-s model with standard training procedures, there was an improvement of 4% in mAP@0.5:0.95, 1.3% in mAP@0.5, and 8.1% in mAP@0.75. This research introduces a novel method for accurate detection of cotton aphids in the field, which is crucial for effective pest management and timely intervention.

BackgroundThe formation of symbiotic relationships between invasive plants and soil microorganisms in invaded regions, which enhances their adaptive capacity has been extensively studied. Bacillus, as a representative soil beneficial microorganism, can be recruited by invasive plants to their rhizosphere to promote growth. However, it remains unclear how dominant Bacillus species in the rhizosphere changes, and what feedback effects these changes may have, when invasive plants encounter biotic resistance in the invaded region, particularly from plant competition and insect herbivory.ResultsThis study investigated the contents of Bacillus idriensis, B. mycoides, B. thuringiensis in the rhizosphere soil of Ageratina adenophora under different biotic resistance. It showed that B. idriensis exhibited the highest increase in the rhizosphere during plant competition, whereas B. thuringiensis showed the most significant increase under Aphis gossypii infestation. The effect of these Bacillus species on the competitive interactions between A. adenophora and native plant Rabdosia amethystoides were assessed. Inoculation with B. idriensis led to an 185.66% increase in biomass for monocultured A. adenophora and a 175.83% increase in mixed culture, thereby enhancing the positive effect of interspecific competition on the growth of A. adenophora. Additionally, the responses of A. adenophora to infestation by the generalist herbivorous A . gossypii following Bacillus inoculation were examined. B.thuringiensis inoculated significantly increased the levels of jasmonic acid, total phenols, flavonoids in A. adenophora infested by A. gossypii by 49.38%, 20.78%, 18.59%, while significantly reducing the survival rate and nymph density of A. gossypii, indicating enhanced resistance to the herbivore. B. idriensis improved the tolerance of A. adenophora to A. gossypii through growth promotion.ConclusionOur findings demonstrate that the abundance of distinct Bacillus species in the rhizosphere of A. adenophora varies in response to diverse biotic resistance encountered in the invaded region. These rhizobacterial interactions generate specific feedback effects that collectively enhance the invasiveness of the species.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-025-07884-x.