Tuta Absoluta Research Articles (Page 1)

A systemically applied nanoparticle-based dsRNA biopesticide reduces Tuta absoluta survival.

The South American tomato pinworm, Tuta absoluta (Meyrick), is among the most destructive invasive pests of tomato globally. The diamide insecticide tetraniliprole is increasingly used for its management. This study examines the sublethal effects of tetraniliprole on T. absoluta larvae, with a focus on its transgenerational impacts. Bioassays demonstrated that tetraniliprole was highly toxic to third-instar T. absoluta larvae, with an LC50 of 0.029 mg/L. Sublethal (LC10) and low lethal concentrations (LC30) were used to investigate their impact on developmental, reproductive, and population parameters across two subsequent generations (F1 and F2). In the parental (F0) generation, exposure to tetraniliprole at both concentrations significantly prolonged larval and pupal durations and reduced adult longevity and fecundity. In both F1 and F2 generations, concentration-dependent effects were observed-LC10 accelerated development and enhanced fecundity and population growth, indicative of a hormetic response, whereas LC30 delayed development and suppressed reproduction and survival. Life table analyses revealed significant changes in the r, λ, and T, particularly under LC30. Additionally, the RT-qPCR analysis revealed the downregulation of development and reproduction-related genes (Vg, VgR, and JHBP) in the F0 generation following exposure to tetraniliprole (LC10 and LC30). In contrast, these genes were upregulated in the progeny generations (F1 and F2) at LC10. Furthermore, the overexpression of key detoxification genes, particularly CYP4M116 and CYP6AW1, persisted across all three generations. Taken together, these findings reveal a substantial risk of unintended population resurgence (hormesis effects) at sublethal concentrations, underscoring the importance of integrating transgenerational consequences into insecticide resistance management programs for sustainable control of this key insect pest.

Simple SummaryThis study examined how gamma radiation at a substerilizing dose of 300 Gy affects the invasive tomato pest Tuta absoluta, focusing on male moths and their F1 offspring. An age-stage, two-sex life table approach was used to assess the F1 generation’s development, survival, and reproduction. Compared to non-irradiated groups, the irradiated F1 moths experienced longer development times, lower survival rates, shorter lifespans, and fewer offspring. Key population metrics also declined, with some even turning negative, indicating population decline may occur. Additionally, transcriptomic analysis identified 232 differentially expressed genes between irradiated and non-irradiated groups. These genes are involved in crucial processes such as metabolism, hormone production, and immune response. The expression levels of 13 key genes related to male fertility were reduced in irradiated males. Overall, this study shows that irradiated male T. absoluta can pass harmful effects to their offspring, impairing growth and reproduction. This provides a theoretical basis for controlling T. absoluta through the sterile insect technique and highlights potential genetic targets for a genetic sterile insect technique strategy.The tomato leaf miner, Tuta absoluta, is a major pest affecting economically important crops like tomatoes, causing significant global economic losses and exhibiting increasing resistance to pesticides. The sterile insect technique (SIT) is an environmentally friendly control method that is sustainable for both ecosystems and human health. This study used age-stage, two-sex life tables, transcriptomics, and bioinformatics to analyze how irradiation affects the reproductive capacity of male T. absoluta. Compared to the control group, the irradiated offspring showed reduced total lifespan, pre-adult survival rate, net reproductive rate, and intrinsic growth rate. Transcriptomic analysis identified 232 differentially expressed genes (DEGs). GO and KEGG enrichment analyses revealed that irradiation impacted biological processes in male adults related to key biomolecules, hormone metabolism and synthesis, and immune responses. Of the 14 selected genes validated through RT-qPCR, 13 were identified as potential regulators of male reproductive capacity, offering possible targets for controlling T. absoluta using inherited sterility-based SIT strategies. Overall, this study provides a theoretical basis for applying SIT in field control and identifies potential genetic targets for managing T. absoluta populations through a genetic sterile insect technique.

Tomato (Solanum lycopersicum) production is increasingly threatened by Tuta absoluta, a destructive pest that compromises yield and quality. To explore sustainable alternatives to conventional insecticides, we investigated the jasmonate-mediated defense pathway by performing a genome-wide characterization of the JAZ gene family in S. lycopersicum. A total of 39 SlJAZ genes were identified and mapped to 12 chromosomes. Detailed analysis revealed conserved motifs, diverse exon-intron structures, four major phylogenetic groups, and the presence of multiple MeJA- and stress-responsive cis-elements. Synteny analysis indicated gene duplication events and evolutionary conservation with Arabidopsis and potato. Small RNA predictions suggested that 33 SlJAZ genes are targeted by 69 microRNAs, implying multilayered regulation. Transcriptome analysis under four treatment conditions-mesoporous silica nanoparticles (MSNs) ± pest infestation-revealed 21 differentially expressed SlJAZ genes. SlJAZ1, SlJAZ19, SlJAZ20, and SlJAZ22 were notably upregulated under the combined MSN and pest treatment, with expression patterns validated by qRT-PCR (R2 = 0.92). Phenotypic assessment of leaf damage index, larval survival rate, and number of leaf mines showed reduced pest activity in MSN-treated plants. Regression analysis demonstrated significant negative correlations between expression levels of SlJAZ20, SlJAZ26, and SlJAZ29 and pest-related damage traits. These findings indicate that MSNs function as effective elicitors of JA-responsive defense in tomato and modulate the expression of specific JAZ genes linked to enhanced resistance. The study provides a valuable foundation for integrating nanotechnology with molecular defense strategies to promote sustainable pest management.

Simple SummaryDeveloping effective tools for the sustainable management of Tuta absoluta (Lepidoptera: Gelechiidae) remains a challenge. Pheromone-based control is attracting growing attention for managing this moth pest. In the present study, we assessed the efficacy of a mating disruption approach relying on biodegradable pheromone dispensers, tested at 300 and 500 dispensers/ha, for the control of T. absoluta on greenhouse tomato. The mating disruption strategy was coupled with a reference base treatment that alternates the most commonly used insecticides for the pest (the insecticide-based grower’s standard). Mating disruption with biodegradable dispensers achieved a significant reduction in T. absoluta male catches and leaf and fruit damages when compared to those obtained with the grower’s standard treatment alone, and performed better than commercial non-biodegradable dispensers. Overall, our study sheds light on the intriguing potential of biodegradable dispensers for T. absoluta management on greenhouse tomato.IPM approaches based on pheromone-based techniques for the management of the South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), are of great interest. We evaluated the effectiveness of mating disruption (MD) experiments against T. absoluta using a biodegradable pheromone dispenser (Isonet-T TT BIOX234) in greenhouse-grown tomatoes over two years in southern Italy. A base treatment alternating the most used insecticides for the pest, i.e., the farmer treatment schedule (FTS), was assigned as a reference, and two MD dispenser densities (i.e., 300 and 500 dispensers/ha) were compared with the MD commercial product Isonet T at 1000 units/ha. We conducted two trials on crops at a density of 37,000 plants/ha. Pest flights were monitored in summer–autumn 2023 and 2024 with pheromone-baited Delta traps. The FTS ensured a generally low level of T. absoluta attacks (about 1 leaflet/leaf and 1/300 fruits). Even so, mating disruption resulted in further appreciable reductions in the presence and attacks of the target pest: 89%, 76% and 52% fewer catches; 61%, 45% and 37% fewer mined leaflets; and 76%, 59% and 54% fewer attacked fruits, for Isonet-T TT 500, Isonet-T TT 300 and Isonet T 1000, respectively. Overall, MD biodegradable dispensers could be a valuable tool for controlling T. absoluta in greenhouse-grown tomatoes, while also reducing plastic waste in the agricultural setting.

Tomato leaf miner, Tuta absoluta (Meyrick), is a highly invasive and oligophagous pest of tomato that causes severe damage to the tomato crop and threatens its production globally. Recently, in Pakistan, T. absoluta has become a major problem for the tomato crop. Considering the synthetic insecticides as first choice for its management, a laboratory study was conducted to determine the effectiveness of four different new chemistry synthetic insecticides, i.e., Chlorantraniliprole, Chlorantraniliprole + Thiamethoxam, Flubendiamide, and Spirotetramat against 3rd instar larvae of T. absoluta. Three various concentrations of each insecticide i.e., 5, 10, and 15 ppm based on their recommended field doses were used through leaf dipping method under mining (larvae inside mines) and non-mining (larvae released after the treatment) conditions. Mortality of larvae was recorded at 24, 48, and 72 hours after exposure to the insecticide. The results indicated that Chlorantraniliprole + Thiamethoxam and Chlorantraniliprole insecticides were found to be most effective against T. absoluta larvae and caused maximum mortality percentage at higher concentrations after 72 hours of exposure. Flubendiamide showed moderate effectiveness, whereas Spirotetramat exhibited minimal mortality at all concentrations, regardless of time exposure. Higher mortality was recorded on unmined leaves compared to mined leaves. According to the findings, Chlorantraniliprole + Thiamethoxam and Chlorantraniliprole alone were most effective against T. absoluta larvae under mining and un-mining leaf conditions. Chlorantraniliprole-based insecticides should be a priority in IPM, while monitoring their use and rotating them regularly can prevent resistance. Therefore, it is suggested that field trials should be conducted to determine the effectiveness of Chlorantraniliprole + Thiamethoxam and Chlorantraniliprole against T. absoluta.

The tomato leafminer moth, Tuta absoluta (Meyrick), and the potato tuber moth, Phthorimaea operculella (Zeller), are closely related gelechiid species that have rapidly invaded tropical, subtropical, and Mediterranean regions worldwide, causing severe damage to solanaceous crops. We used the optimized MaxEnt model combined with 19 bioclimatic variables to comprehensively predict their potential distributions under current and future climate scenarios. While the distribution areas of the species overlapped significantly, our models predicted T. absoluta could potentially establish into high-latitude and arid areas. To further explore their adaptive mechanisms, we conducted comparative genomics based on the genomes of both species and 20 other insect species. Despite their close relationship, T. absoluta possessed 5.5 times more unique gene families than P. operculella, along with significantly expanded gene families associated with pesticide resistance (P450s: 92 vs. 86), extreme temperature tolerance (heat shock proteins [HSPs]: 62 vs. 58), and desiccation stress tolerance (aquaporins [AQP]: 12 vs. 9). These genomic features suggest that T. absoluta will adapt faster to environmental challenges and has greater potential to invade new areas compared to P. operculella. This study elucidates the patterns of potential distribution and genome evolution for T. absoluta and P. operculella, highlighting their distinct invasion and adaptation strategies. The findings provide both a novel perspective on the habitat suitability of these invasive pests and a scientific basis for climate-adaptive management strategies.

Tomato leafminer (TLM), Phthorimaea absoluta Meyrick, and the potato tuber moth (PTM), Phthorimaea operculella (Zeller), are significant invasive pests with similar ecological niches, investigated interspecific competition and reproductive interference of TLM and PTM on 2 host plants the species have in common, tobacco and potato. In cage experiments PTM replaced TLM after 2 successive generations on tobacco and TLM replaced PTM after 3 generations on potato. In tobacco experiments, PTM did not significantly affect the oviposition of TLM. Conversely, TLM presence stimulated PTM oviposition: PTM egg-laying was significantly higher in groups exposed to female TLM adults (110.81 ± 7.59 eggs/female) or male TLM adults (112.17 ± 5.87 eggs/female) compared to the PTM-only control group (90.81 ± 4.89 eggs/female). In potato experiments, there were no significant differences among treatments. In tobacco greenhouse experiments, when TLM was in the presence of PTM, the number of F1 adults of TLM decreased significantly. In the presence of TLM, there was a significant increase in the number of PTM adults in the F1 generation. In potato greenhouse experiments, our results showed no significant differences in the counts of F1 generation adults or the sex ratio. Interspecific interactions were asymmetric depending on the host plant. On tobacco, PTM exhibited stronger competitiveness and was able to displace TLM. However, on potato, TLM displaced PTM, indicating a stronger competitive ability of TLM on that host. These results demonstrate the importance of context, including host plant or other environmental conditions, when assessing the potential strength and direction of interspecific interactions.

Studies on the olfactory sensory systems of pests have substantial theoretical potential for the development of eco-friendly control strategies. Tuta absoluta (Meyrick, 1917), one of the most damaging invasive pests of Solanaceae crops, has limited research on its sex pheromone recognition mechanism. In the present study, five PBPs, including three PBP1, PBP2, and PBP3, were identified in T. absoluta. Four TabsPBPs were predominantly expressed in the antennae of male moths, of which TabsPBP1.1 had a strong and similar binding affinity to sex pheromones (3E,8Z,11Z)-tetradecatrien-1-yl acetate (TDTA) and (3E,8Z)-tetradecadien-1-yl acetate (TDDA), and TabsPBP3 had a stronger binding affinity to TDDA than the primary sex pheromone component TDTA. TabsPBP1.3 did not show a sex-biased expression pattern in the antennae, but showed binding affinity to sex pheromones and the host plant volatile terpinolen. Molecular dynamics simulations predicted the key active sites for the binding of TabsPBPs to sex pheromones. TabsPBP1.1/1.3/3 could serve as potential targets for the development of attractants or repellents.

To identify highly virulent Beauveria bassiana strains against Tuta absoluta and evaluate their biocontrol potential, four strains were phylogenetically characterized via ITS sequence analysis of rDNA and assessed for virulence against second-instar T. absoluta larvae. Foliar spray and root irrigation methods were used to establish B. bassiana endophytic colonization in tomato plants, with untreated plants serving as controls. A population life table was constructed to quantify the impact of colonized plants on larval development, fecundity, and key demographic parameters. Results showed variation in virulence among the four B. bassiana strains Bb1Bm, Bb2Bm, Bb1M, and BbC with Bb1Bm exhibiting the highest pathogenicity (85.00% corrected mortality at 1 × 108 spores/mL). Maximum endophytic colonization in tomato leaves was observed 14 days post-inoculation with both foliar spray and root irrigation treatments. Life table analyses revealed that T. absoluta feeding on colonized plants exhibited significantly reduced survival rates, shorter adult lifespans, and lower female fecundity compared to controls. Key population parameters, including net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ), were significantly reduced, while mean generation time (T) was significantly prolonged. These findings highlight the dual role of B. bassiana in T. absoluta management, demonstrating its potential as both a direct pathogen and an endophytic biocontrol agent capable of disrupting pest population dynamics.

Photosystem II (PSII) is very sensitive to both biotic and abiotic stress conditions, mirroring global climate changes. Crop production worldwide faces rising hazards from the increased duration, frequency, and intensity of drought stress episodes as a result of climate change, and its effects, when combined with biotic stress, are becoming more noticeable. In the present work, we examined PSII responses of well-watered (WW) tomato plants or mildly drought-stressed (MDS) plants to 20 min of Tuta absoluta larvae feeding. The effective quantum yield of PSII photochemistry (ΦPSII) of the whole leaf in WW plants, after 20 min of larvae feeding, compensated for the reduction in ΦPSII observed at the feeding area. In contrast, the reduced ΦPSII at the feeding areas of MDS plants, after 20 min of larvae feeding, was not compensated at the whole-leaf level because of the drought stress. The increased ΦPSII and electron transport rate (ETR) at the whole-leaf level in WW plants was attributed to the increased fraction of open PSII reaction centers (qp), since there was no difference in the efficiency of the open PSII reaction centers (Fv'/Fm') before and after feeding. Therefore, the response of PSII photochemistry in WW plants to short-term biotic stress resulted in an overcompensation reaction, which developed a whole-leaf photosynthetic enhancement. However, short-term biotic stress in combination with mild abiotic stress resulted in decreased PSII photochemistry. It is concluded that increased crop damage is likely to occur due to the global climate-change-induced drought episodes, influencing insect herbivory.

The invasive tomato leafminer Tuta absoluta has recently caused heavy losses to tomato growing areas around the world including Pakistan. Considering its significant damage potential, it is essential to conduct experiments using locally available botanicals and synthetic insecticides. Therefore, studies were conducted at a farmer’s field in the district Shaheed Benazir Abad, Sindh, Pakistan during complete tomato season of 2023-24. Synthetic insecticides, i.e., Tracer 450SC ® (Spinosad 480 g/L), Belt 480 SC ® (Flubendiamide 480 g/L), Novastar 56EC ® (Bifenthrin 5%+ Abamectin 0.6%), Talstar 10EC ® (Bifenthrin), and Trigard 750 g/kg ® (Cyromazine) and botanical insecticides, i.e., Neem (Azadirachta indica A. Juss.), Tobacco (Nicotiana tabacum L.), Datura, (Datura stramonium L.), Peppermint (Mentha piperita L.), and Eucalyptus (Eucalyptus camaldulensis Dehn.), along with untreated control were evaluated against T. absoluta During both sprays, synthetic insecticides were found to be comparatively more effective than botanicals, with Flubendiamide and Spinosad being the two most effective insecticides. The effectiveness of all insecticides was comparatively better in the second spray than first spray. After one week of the two sprays, the maximum infestation reduction on tomato leaves and fruits was recorded with Flubendiamide (73.34% and 85.60%, respectively), followed by Spinosad (70.58% and 83.57%, respectively), whereas Eucalyptus and Datura were the least effective insecticides. Among botanicals, Neem resulted in a maximum corrected reduction in T. absoluta infestation on tomato leaves (52.33%) and fruits (55.20%). Due to the effectiveness of insecticides in reducing T. absoluta infestation, a significant effect on tomato fruit yield was also observed as maximum yield was recorded with Flubendiamide (433.40 ± 5.46 maunds per acre) and Spinosad (420.80 ± 3.20 maunds per acre) treatments, whereas neem (389.60 ± 4.86 maunds per acre) gave maximum yield among botanicals. Therefore, it is recommended that due to the better performance of Flubendiamide and Spinosad, they should be included in the integrated management of T. absoluta infestation in tomatoes, whereas Neem can also be used as botanical insecticide due to its effectiveness against it.

Abstract Phthorimaea (Tuta) absoluta (Meyrick) (Lepidoptera: Gelechiidae), commonly known as the South American leafminer, was first detected in South Africa in 2016. Its resistance to various insecticides in multiple countries underscores the urgent need for integrated pest management (IPM) strategies. Entomopathogenic nematodes (EPNs), traditionally used against soil-dwelling pests, are receiving increasing attention for foliar applications, due to rising insecticide resistance, regulatory restrictions on chemical use and the growing availability of EPN-based products on the market. This study assessed the efficacy of four indigenous EPN species, viz., Steinernema jeffreyense, S. yirgalemense, Heterorhabditis baujardi, and H. noenieputensis against mined final instar larvae and pupae of P. absoluta in laboratory bioassays and on tomato seedlings in a greenhouse experiment. In laboratory bioassays, all EPN species achieved approximately 100% larval mortality, while pupal mortality remained below 42%. In the greenhouse trails, tomato seedlings infested with P. absoluta final instar larvae were treated with EPNs at concentrations of 250, 500, 1,000, and 2000 infective juveniles (IJs) mL−1. Phthorimaea absoluta larvae were collected 24 h post-treatment and monitored for mortality at 72 h under controlled conditions. Despite low nematode penetration rates in the greenhouse trials, both S. jeffreyense and S. yirgalemense achieved over 80% larval mortality at 1000 and 2000 IJs mL−1. These findings highlight the potential of EPNs, particularly S. jeffreyense and S. yirgalemense, as promising components of IPM programs targeting P. absoluta in greenhouse-grown tomato production in South Africa.

The efficacy of three native isolates of entomopathogenic nematodes: Heterorhabditis bacteriophora (H), H. indica (Fn) and Steinernema affine (313) was assessed against 3rd and 4th instar larvae (both outside and inside leaf tunnels) and pupae of Tuta absoluta, a destructive pest in Syria, at 25°C. In the laboratory, the isolates were tested on larvae outside leaf tunnels, at different doses 1, 5, 10, 15, 25 and 50 infective juveniles IJs/larva. The results obtained showed the susceptibility of larval instars to nematode infection, with variation according to the isolate, the concentration, and the larval instar stage inoculated. The isolate H exhibited the highest mortality rates across all treatments, followed by the isolate Fn, while the isolate 313 had the least virulence. The 50% lethal doses (LD50) for the three isolates against the 3rd and 4th larval instars, were 9.62 and 7.57 IJs/larva for isolate H; 12.33 and 8.24 for isolate Fn; 30.36 and 24.20 for isolate 313, respectively. The two most efficient isolates from the previous experiment, H and Fn, demonstrated the capability to access and kill larvae within the leaf tunnels with no significant difference between them. The H isolate exhibited mortality rates of 37.12 and 45.66%, whereas the Fn isolate produced mortality rates of 34.33 and 41.12% for 3rd and 4th instar larvae, respectively. Nevertheless, their efficacy on pupae was comparatively lower, with the H isolate displaying the highest mortality rate of 12.33%. In pot experiments, two concentrations (500 and 1000 IJs/ml) of H and Fn isolates were applied, with no significant differences observed between the two isolates. Although their efficacy was limited on pupae, the virulence on larvae instars was evident and increased with heightened concentrations and instar progression, achieving mortality rates for the 4th instar of 94.27 and 83.87% outside and inside leaf tunnels of the H isolate, and 91.66 and 80.10% for the Fn isolate, respectively. These findings suggest that entomopathogenic nematodes adapted to moderately warm temperatures are considered promising effective biological control agents against Tuta absoluta. Further in-depth research and practical applications within greenhouses are needed. Keywords: Biological control, entomopathogenic nematodes, Heterorhabditis, Steinernema, Tuta absoluta, LD50.

This study was conducted at College of Sciences-Mustansiriyah University, aimed to examine the functional response of predator green lacewing, Chrysoperla carnea (Stefens) (Neuroptera: chrysopidae) The predator is one of the important natural enemies of members of the family Gelechiidae eggs. Result obtained showed that the curves of functional response of the predator green lacewing, C. carnea larvae on various densities of tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae) eggs showed that the larvae of predator belong to second type (Cyrtoid) of functional response. The rate of attack coefficient (a) increased, whereas the handling time (Th) was reduced, and the highest attack coefficient was 2.558 for the 2nd larval stage and the lowest attack coefficient was 1.509 for the 3rd larval stage. However, the highest handling time was 23.274 minutes for 2nd larval stage and the lowest handling time was 10.651 minutes for 1st larval stage. Keywords: Handling time, attack coefficient, Chrysoperla carnea, Tuta absoluta, functional response.

Harnessing indigenous entomopathogenic fungi for biopesticide development against Tuta absoluta in Tanzania

Plant growth-promoting rhizobacteria (PGPR) offer a sustainable strategy for enhancing crop productivity and suppressing phytopathogens. In this study, seven bacterial isolates obtained from the rhizosphere of healthy tomato plants were evaluated for their antagonistic activity against the fungal pathogen Passalora fulva, the leaf miner Tuta absoluta, and their effects on tomato growth. In vitro dual-culture assays revealed that isolates IQR1, IQR2, IQR3, and IQR5 significantly inhibited P. fulva mycelial growth, with inhibition rates exceeding 35%. Volatile organic compounds (VOCs) produced by the bacterial isolates exhibited considerable antifungal activity, with IQR5, IQR1, and IQR2 achieving over 84% inhibition. Molecular identification based on 16S rDNA sequencing indicated that these isolates belong to distinct taxa: Leucobacter aridicolis (ON799334.1) (genus Leucobacter), Paenochrobactrum sp. (JF804769.1) (genus Paenochrobactrum), an uncultured bacterium (JQ337400.1) (genus Psychrobacter), and marine bacterium AK6_052 (KF816539.1) (genus Brevundimonas). Under greenhouse conditions, isolates IQR3, IQR5, and IQR1 reduced disease incidence of P. fulva to 20-26%. The same isolates also promoted plant growth, enhancing stem height and collar diameter. In addition, IQR5 significantly reduced T. absoluta larval density and foliar damage, with the number of larvae per leaflet decreasing to 1.42, compared to 3.20 in the control. These findings highlight the potentials of these rhizobacterial strains-particularly IQR5-as effective biocontrol agents and biofertilizers for integrated pest and disease management in tomato cultivation.

Tuta absoluta has evolved resistance to many biological insecticides, resulting in significant annual agricultural and economic losses. Glutathione S-transferases (GSTs) are one of the major insect detoxification enzyme systems. However, the detoxification metabolism of GSTs in T. absoluta against biological insecticides remains poorly understood. In this study, We identified five key GST genes (TaGSTs1, TaGSTs2, TaGSTe1, TaGSTe3, and TaGSTd1) by screening from the comparative transcriptomes of two regional populations of T. absoluta in Xinjiang, China. Among the five GSTs, TaGSTs1 exhibited a significantly high expression level during the larval stage of T. absoluta following exposure to the LC50 dose of spinetoram. This gene was subsequently cloned, and its expression was knocked down using RNA interference to further analyse its role in the detoxification of spinetoram, as well as in the growth and development of T. absoluta. The results showed that TaGSTs1 contains a typical GST gene domain and was highly conserved within the Lepidoptera clade. Silencing of the TaGSTs1 gene led to a significant increase in the susceptibility of T. absoluta to spinetoram, as evidenced by an extension in the duration of leaf-mining and in the development time from the 2nd to the 4th instar larval stage, which were 35.7% and 19.6% longer, respectively, than those of ddH2O and dsGFP controls. Furthermore, the mortality rate of larvae treated with dsTaGSTs1 reached 57.3% by the 7th day. These findings indicate that TaGSTs1 plays a crucial role in the detoxification of spinetoram and in the growth and development of T. absoluta larvae.

The tomato leafminer (Tuta absoluta) is a globally invasive pest that causes severe yield losses in tomato crops. Nanotechnology-based strategies offer promising alternatives to conventional insecticides. This study examines the physiological, biochemical, and demographic responses of T. absoluta following exposure to mesoporous silica nanoparticles (MSNs) applied to tomato leaves at concentrations of 0, 3, 30, and 300 mg L-1. Comprehensive assessments were conducted, including digestive and detoxifying enzyme activities in the insect, neurotoxicity indicators, life table parameters, and antioxidant responses in the host plant. At 30 mg L-1, MSNs significantly impaired larval development, fecundity, and survival of T. absoluta without inducing phytotoxicity. Tomato plants treated at this concentration exhibited enhanced antioxidant enzyme activity (SOD, CAT, POD) and a reduced malondialdehyde (MDA) content, indicating an active oxidative defense. These plant responses were significantly correlated with changes in insect fitness traits, suggesting a plant-mediated effect on pest physiology. Digestive enzyme disruption, decreased acetylcholinesterase activity, and extended developmental periods contributed to suppressed population growth, as evidenced by reductions in the intrinsic rate of increase (r), net reproductive rate (R0), and fecundity. At 300 mg L-1, however, severe phytotoxicity and enzymatic collapse were observed in both plant and insect systems. These findings highlight moderate concentration of MSNs (30 mg L-1) as a promising dose for sustainable and host-safe pest management, offering multi-targeted suppression of T. absoluta through combined plant and insect biochemical pathways.

Background and aim The use of synthetic pesticides presents environmental and health hazards, necessitating the development of environmentally sustainable alternatives. This study seeks to synthesize and assess the insecticidal effectiveness of iron oxide nanoparticles obtained from the green seaweed Ulva lactuca against different instars of lepidopteran and dipteran insects. Experimental approach The synthesis of Fe2O3 nanoparticles was conducted via U. lactuca extract, followed by characterization via FTIR, XRD, TEM, SEM, and EDS studies. Larvicidal bioassays were performed at concentrations between 50 and 200 µg/mL for 48 hours targeting second to fourth instar larvae of Spodoptera frugiperda, Spodoptera litura, Helicoverpa armigera, Tuta absoluta, Aedes aegypti, and Culex quinquefasciatus. Key findings FTIR analysis showed Fe–O bonding at 668 cm−1, while XRD revealed distinct diffraction peaks at 2θ values of 43.2°, 50.1°, and 62.1°, thereby substantiating the crystalline structure of Fe2O3. TEM and SEM demonstrated consistently spherical nanoparticles (∼100 nm), while EDS verified iron as the predominant element. The Fe2O3 nanoparticles demonstrated significant dose-dependent larvicidal efficacy, with maximum mortality rates of 96.22% in H. armigera (LC50 = 216.76 µg/mL), 96.10% in T. absoluta (LC50 = 116.36 µg/mL), and 97.0% in Ae. aegypti (LC50 = 136.81 µg/mL). Conclusions The findings indicate the significant and extensive insecticidal efficacy of U. lactuca-synthesized Fe2O3 nanoparticles, endorsing their application as an environmentally benign nanobiopesticide.