Beneficial microbes are increasingly applied as biocontrol agents to enhance soil vitality and crop productivity. However, given that alterations in soil conditions can propagate across trophic levels, it is essential to evaluate the broader ecological effects and biosafety of soil-applied microorganisms on higher trophic organisms. This study investigates the impact of two beneficial soil-applied microbes, Bacillus cereus and Chryseobacterium cucumeris, on the soil-borne plant pathogenic fungus Fusarium oxysporum, cucumber, the two-spotted spider mite Tetranychus urticae and its predator Phytoseiulus persimilis. Both bacterial agents were effective against F. oxysporum and demonstrated the ability to be transmitted across plant-herbivore-predator trophic levels. Notably, B. cereus was vertically transmitted from adults to eggs in P. persimilis, whereas C. cucumeris was only detected in the digestive tract. Bacillus cereus had no significant effects on fitness of both mite species. In contrast, C. cucumeris significantly reduced survival and reproduction of T. urticae and survival of P. persimilis adults, but not egg production. Greenhouse trials confirmed that soil application of C. cucumeris around the roots of cucumber, and subsequent uptake in the foliage could significantly suppress the survival and reproduction of both mite species. This study demonstrates that soil-introduced biocontrol microbes can transmit across trophic levels and may exert non-target effects on predators. The findings underscore the importance of considering indirect ecological risks and biosafety implications for beneficial invertebrates when deploying microbial biocontrol agents in integrated pest management systems. © 2026 Society of Chemical Industry.

Thrips parvispinus is an invasive and highly polyphagous pest that has recently expanded its distribution worldwide, creating an urgent need for effective and sustainable management strategies. Functional response analysis provides baseline information for evaluating predator performance and supporting the development of biological control programs. In this study, we investigated the functional responses of 3 generalist predators, Amblydromalus limonicus, Amblyseius swirskii, and Franklinothrips vespiformis, against first- and second-instar larvae of T. parvispinus under laboratory conditions. Predation assays were conducted across multiple prey densities, and functional response type, attack rate, and handling time were estimated using logistic regression and random predator equation. All predator groups for which parameter estimation was possible exhibited Type II functional responses. Female predatory mites showed higher proportion of prey consumed than males, whereas functional response determination for males was frequently limited by low consumption, particularly when larger prey stages were provided. F. vespiformis showed substantially higher maximum consumption and shorter handling time than predatory mites. Between mite species, A. limonicus tended to perform better at low prey densities, whereas A. swirskii exhibited higher maximum consumption. Overall, all 3 predators demonstrated potential as biological control agents of T. parvispinus. The functional response parameters obtained in this study provide baseline information for developing biological control programs targeting this invasive thrips species.

Cannibalism and intraguild predation (IGP) are common interactions among predators that can influence the effectiveness of biological control agents. The minute pirate bug Buchananiella whitei is a recently commerciali sed biocontrol agent in New Zealand, but its intraspecific predation and interactions with potentially co-occurring predatory mites remain poorly understood. This study examined cannibalism within B. whitei, as well as IGP between first-instar B. whitei nymphs and adult females of seven predatory mite species (Phytoseiidae and Laelapidae), using observations in enclosed setups with emphasis on the role of extraguild prey availability (dried fruit mite Carpoglyphus lactis). Both cannibalism and IGP were observed, and their occurrence was strongly influenced by extraguild prey availability. No predation on B. whitei eggs was observed in either cannibalism or IGP. Cannibalism occurred only in adult-nymph interactions, and its prevalence was greatly reduced by the presence of extraguild prey. IGP was more frequent in the absence of extraguild prey. First-instar B. whitei nymphs preyed on most predatory mite species, but reciprocal predation was only observed with Neoseiulus cucumeris and Stratiolaelaps scimitus. Differences in body size among predator species partly contributed to the observed outcomes. These findings indicate that although cannibalism and IGP can occur in systems involving B. whitei, their ecological significance is probably limited when alternative preyare available. Predatory mites are therefore unlikely to substantially suppress B. whitei populations. A better understanding of these trophic interactions will improve the use of B. whitei and other natural enemies in biological control programs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Tetranychus urticae is a major agricultural pest mite whose rapid evolution of pesticide resistance necessitates innovative control strategies. RNA interference (RNAi) offers a promising alternative to chemical pesticides for its high specificity, efficiency, and environmental safety. Ecdysteroid signaling genes, which regulate molting and development in arthropods, represent potential RNAi targets for inducing lethal molting defects. This study investigated the roles of ecdysteroid signaling pathway genes in T. urticae molting and evaluated the potential of fusion double-stranded RNA (dsRNA) constructs targeting multiple genes to enhance RNAi efficacy. The expression profiling revealed that TuE74, TuECR, TuHR4, TuE93, and TuHR3 were highly expressed during the molting stage of T. urticae. RNAi-mediated silencing of these genes, particularly TuECR, TuHR3, TuHR4, and TuE74, caused distinct molting defects and high mortality. Fusion dsRNAs targeting combinations of these genes (ECR-HR3-HR4 or ECR-HR3-E74) achieved stronger and more coordinated gene silencing, lower median lethal concentration (LC50) and LC90 values than single-gene dsRNA (dsTuHR3), and exhibited cross-species efficacy against Tetranychus cinnabarinus and Tetranychus evansi. Importantly, the fusion dsRNAs showed no adverse effects on the predatory mite Neoseiulus californicus, supporting their biosafety. Spray-based delivery of fusion dsRNA significantly delayed molting, confirming its biological activity, although optimization of delivery efficiency is still required to achieve complete developmental arrest. The present study demonstrates that multi-target fusion dsRNA can substantially enhance RNAi efficacy, broaden control spectra across pest mite species, and maintain environmental safety. These results provide a molecular basis and applied framework for the development of next-generation RNAi-based acaricides for sustainable spider mite management. © 2026 Society of Chemical Industry.

Predators suppress pest populations not only through direct consumption but also via non-consumptive effects (NCEs), in which prey perceive predation risk and alter behaviors, physiology, and life-history strategies. Despite the growing recognition of the importance of NCEs in biological control, most studies focus on cues from actively feeding predators, while the role of non-feeding stages, such as predator eggs, remains poorly understood. Here, we investigated whether eggs of the predatory mite Phytoseiulus persimilis function as intensity-dependent risk cues that influence the performance and population growth of the invasive spider mite Tetranychus ludeni. Exposure to P. persimilis eggs significantly altered T. ludeni life-history traits in a density-dependent manner, even in the absence of direct predation. Increasing predator egg density reduced female longevity, reproductive rate, and total fecundity, delayed reproductive onset, but accelerated early egg production. Exposure to predator eggs also generated pronounced transgenerational effects that prolonged egg and female offspring development, reduced egg hatching, and lowered immature survival. These individual-level responses translated into strong population-level consequences, which significantly decreased the net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ), but increased population doubling time (Dt) as predation stress intensified. Our results demonstrate that predator eggs induce intensity-dependent NCEs that significantly suppress spider mite population growth. By extending fear-mediated effects from non-preying predator stages, this study broadens the functional scope of biological control and highlights the ecological significance of early predator cues in regulating pest populations. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The tobacco thrips, Thrips parvispinus, is threatening greenhouse horticulture crops worldwide. In a laboratory trial, gravid females of Amblyseius swirskii, Amblydromalus limonicus, Neoseiulus cucumeris and Transeius montdorensis consumed between 2 and 3.5 first instars of the thrips daily. The predation rates of the phytoseiids tested were lower than those reported when the western flower thrips Frankliniella occidentalis was provided as prey. This predation pattern was confirmed for A. swirskii in a separate trial. In a greenhouse cage trial with sweet pepper plants infested with tobacco thrips, A. swirskii, A. limonicus and N. cucumeris significantly reduced the pest numbers. However, in a commercial Ficus elastica Robusta crop, where A. swirskii and N. cucumeris were introduced weekly, no single predator proved to be sufficiently effective. Larger generalist predators, such as the lacewing Chrysoperla carnea, the predatory thrips Franklinothrips vespiformis, and the predatory bugs Orius laevigatus and Macrolophus pygmaeus were also tested. They reduced populations of tobacco thrips in a cage experiment on sweet pepper. Chrysoperla carnea and F. vespiformis were tested in a commercial Ficus greenhouse and reduced the pest population but were unable to eradicate it. Our results show that the tested mite and insect predators have potential to control tobacco thrips. More research on strategies involving preventative and curative releases of natural enemies, the combination of predatory mites with insect predators or with biopesticides, and the use of supplemental food sources will be needed to curb the spread and damage of T. parvispinus. © 2026 Society of Chemical Industry.

Predatory mites are widely used to control major thrips pests in agricultural systems. The invasive Thrips parvispinus represents a challenge to economically important plants, with limited information available on the potential of predatory mites to control it. Eight commercially available predatory mites in the USA: Amblyseius swirskii, Amblyseius andersoni, Amblydromalus limonicus, Neoseiulus cucumeris, Neoseiulus californicus, Euseius degenerans, Anystis baccarum, and Stratiolaelaps scimitus; and four naturally occurring predatory mites in Florida: Proprioseiopsis ovatus, Neoseiulus longispinosus, Amblyseius largoensis, and Amblyseius adhatodae were evaluated. In choice experiments, predators were exposed to pairs of T. parvispinus stages (first instar-L1, second instar-L2, prepupa, pupa, and adult) to assess preference. Subsequent no-choice assays quantified predation and oviposition on the preferred stage: all phytoseiids were offered L1, P. ovatus prepupae, A. baccarum L2, and S. scimitus L2 or prepupae. Prey consumption and oviposition were recorded every 24h for four days. Neoseiulus longispinosus, A. largoensis, and A. adhatodae did not feed on T. parvispinus. The remaining phytoseiids preferred L1 over L2. Anystis baccarum preferred L2 and adult stages. Stratiolaelaps scimitus showed no stage preference, varying according to the offered stages. When offered L1, the highest predation was recorded for E. degenerans (5.78 L1/day), A. swirskii (4.14 L1/day), and N. cucumeris (3.23 L1/day). When offered L2, A. baccarum consumed 12.88 L2/day and S. scimitus 6.29 L2/day. All predators oviposited when feeding on T. parvispinus. Anystis baccarum produced one mass of 24 eggs, while the highest oviposition was observed for A. swirskii with 1.37 eggs/day. Our results suggest A. baccarum, S. scimitus, E. degenerans, N. cucumeris, and A. swirskii as the most promising predators of T. parvispinus.

Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae) is an important pest of leguminous crops in Asia, severely affecting cowpea quality and causing significant economic losses. The growing resistance of thrips to pesticides has reduced the efficacy of chemical control, thereby highlighting biological control as an increasingly important management strategy. Among natural enemies, predatory mites play a crucial role in suppressing M. usitatus populations. In this study, we evaluated the predatory functional response of Cosmolaelaps leeae Tseng (Laelapidae), a newly discovered indigenous predatory mite from Hainan cowpea fields, against M. usitatus. Results demonstrated that adult female C. leeae exhibited significantly higher predation rates than deutonymphs, consuming an average of 6.53 and 3.53 thrips pupae per day, respectively. Additionally, C. leeae displayed a prolonged oviposition duration (32.74 d) and high cumulative fecundity (84.05 eggs/female) when feeding on the pupae of M. usitatus. Furthermore, a cage experiment was conducted to assess the control efficiency of C. leeae on thrips populations under field conditions. Thrips population suppression increased significantly with escalating C. leeae release rates, demonstrating a density-dependent response, a characteristic of effective biological control agents. In comparative efficiency trials, C. leeae exhibited superior population suppression (1.21-fold, 1.46-fold, 1.71-fold) relative to the established commercial agent Stratiolaelaps scimitus at 3 identical release rates (5, 10, and 20 mites per pot). Overall, the predator mite C. leeae demonstrated significant suppressive effects on M. usitatus populations, suggesting its potential as a promising biological control agent.

The growing urgency of climate change, particularly the rising frequency and severity of extreme heat events, has spotlighted the need for the thermal resilience of natural enemy in pest management. To understand the plasticity of predatory mite in response to thermal adaptation, 3 irradiated strains of Phytoseiulus persimilis Athias-Henriot were induced by Cobalt-60 gamma rays to evaluate the thermotolerance. We integrated both DNA- and RNA-based 16S rRNA gene sequencing to explore whether irradiation and heat stress could impact the microbiome of the predatory mites. Our findings revealed that irradiation enhanced the heat tolerance of predatory mites without compromising fecundity or predation efficiency. Unexpectedly, irradiation had minimal impacts on overall microbial diversity, whereas RNA-based 16S rRNA gene sequencing unveiled irradiation strain-specific enrichment of stress-responsive taxa (e.g., Bacillus sp.), while no such specific enrichment was observed at the DNA level. Furthermore, heat stress significantly restructured the microbiome of P. persimilis, particularly enriching Limnobacter thiooxidans. Methodologically, the DNA/RNA microbial profiles highlighted divergent functional partitioning: Gammaproteobacteria dominated at DNA level, while transcriptionally active Actinobacteria prevailed in RNA level. In conclusion, these results establish a "host-microbiota co-regulation" paradigm for resistance breeding, offering a sustainable pathway to reinforce biological control systems against global warming challenges.

Phytoseiid mites are important biological control agents in Integrated Pest Management (IPM), yet the genetic architecture underlying their adaptive traits remains largely unknown due to limited genomic and genetic resources. Here, we establish an integrated genetic framework for Amblyseius andersoni, generating a genome sequence and developing a high-resolution genetic mapping approach. The genome was assembled using long-read sequencing, yielding a highly contiguous assembly of approximately 202 Mb with 18,923 predicted protein-coding genes and high completeness. We then dissected resistance to two widely used insecticides, deltamethrin and spinosad, as exemplar adaptive traits. Genetic mapping via bulked segregant analysis (BSA) localized deltamethrin resistance to a major-effect QTL encompassing the voltage-gated sodium channel (VGSC). Next, F₂ linkage analysis demonstrated co-segregation of the M918L substitution in VGSC with the resistant phenotype, consistent with a target-site resistance mechanism. Spinosad resistance mapped to a region encompassing the nicotinic acetylcholine receptor (nAChR) α6 subunit. Altered splicing resulting in intron retention was consistent with a dysfunctional receptor in the resistant strain. Together, this framework establishes a powerful genetic tool for resolving genetic determinants of adaptive traits in predatory mites and provides genetic markers that can support breeding programs aimed at enhancing biological control strategies within IPM systems.

Predatory mites transitioning from mass-rearing to field release undergo critical prey switching from rearing hosts to target pests. Understanding temporal adaptation of predatory capacity postswitching is essential for biological control optimization. This study examines how prey switching duration affects predatory performance in Neoseiulus bicaudus Wainstein (Mesostigmata: Phytoseiidae) following from Tyrophagus putrescentiae Schrank (Sarcoptiformes: Acaridae) to Tetranychus turkestani Ugarov et Nikolskii (Trombidiformes: Tetranychidae). The predatory adaptation of female N. bicaudus was assessed during 0 to 7 days postprey switching through integrated approaches: Y-tube olfactometry quantified olfactory responses to T. turkestani, predatory choice tests evaluated feeding preference shifts, Holling type II functional response modeling analyzed predation capacity changes, and field releases on soybean Glycine max (L.) Merr. validated biological control efficacy against T. turkestani. Prey switching enhanced N. bicaudus adaptation to T. turkestani. Olfactory preference increased steadily, with significant shifts by Day 3, peaking at 73.33% by Day 6. Feeding preference shifted from avoidance (D = -0.39, D: prey selectivity index) to strong attraction (D = 0.94), stabilizing >0.9 after Day 4. Though functional response remained Holling Type II, key parameters optimized at Day 4: minimal handling time (Th = 0.04 days), daily maximum predation (1/Th = 26.25), and predation capacity (a/Th = 21.18, where a is attack rate). Field validation showed that the suppressive effect of N. bicaudus (which had experienced prey-switching) on T. turkestani could be enhanced by up to 73.44%. Neoseiulus bicaudus progressively enhances olfactory preference, feeding preference, and predatory capacity toward target prey following prey switching. Implementing this preadaptive strategy significantly improves the mite's field control efficacy against spider mites.

Myzus persicae (Sulzer), a globally significant agricultural pest, poses considerable challenges to conventional chemical control methods due to widespread resistance development. This situation underscores the critical need for integrated pest management (IPM) strategies that combine biological and chemical control measures to achieve sustainable pest suppression. This study investigated the effects of three biopesticides on M. persicae and evaluated their safety for the predatory mite Anystis baccarum (Linnaeus) under laboratory conditions. Additionally, the potential enhanced effects of the combined application of combining these biopesticides with A. baccarum were examined in greenhouse trials. Results showed that all tested biopesticides exhibited concentration-dependent toxicity against M. persicae, with 1-d-old nymphs being the most susceptible life stage, while adults displayed the highest tolerance. Among the tested compounds, cineole and matrine showed higher toxicity than d-limonene. Formulations containing d-limonene (800-fold dilution) and matrine (1200-fold dilution) were considered safe for A. baccarum causing less than 15% mortality. Greenhouse experiments revealed that the combined application of biopesticides and A. baccarum enhanced aphid control efficacy compared to biopesticides alone. Specifically, the integrated treatments increased pest mortality by 4.7% to 14.1% within 72 h, achieved peak control efficacy ∼3 d earlier (reaching 80% control efficiency), and maintained high efficacy levels (63.4% to 76.9%) for up to 27 d post-application. Notably, the combination of matrine and A. baccarum produced the highest corrected efficacy, achieving 76.9% control efficiency at 27 d. These findings demonstrate that integrating matrine with A. baccarum simply enhances pest management efficacy while preserving natural enemy populations, thereby providing a promising strategy for IPM programs targeting M. persicae.

Fungi of the genus Trichoderma have attracted attention because of their potential activity against phytophagous mites; however, information regarding their non-target effects on predatory mites remains limited. This study evaluated the effects of spore suspensions and secondary metabolites of Trichoderma afroharzianum Tr132 and Trichoderma virens Tvr2 on three predatory mite species widely used in biological control programs: Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius swirskii. Predator egg hatchability and adult mortality were assessed under laboratory conditions. Spore suspension treatments did not significantly affect egg hatchability, which remained high (97-99%) across all predator species. In contrast, secondary metabolites slightly reduced egg hatchability to 94-96%, compared with 99.5% in the control. Exposure to spore suspensions caused moderate mortality in adult predatory mites, increasing from 10 to 13% at 3 days post-application (dpa) to 15-19% at 6 dpa. Secondary metabolites produced higher mortality that increased over time, reaching 9-11% at 1 dpa, 17-18% at 3 dpa, and up to 22-25% at 6 dpa. Mortality responses were similar among predator species. Overall, Trichoderma applications had minimal effects on predator egg hatchability but caused moderate mortality in adult predatory mites, particularly following exposure to secondary metabolites. These findings highlight the importance of evaluating the compatibility of Trichoderma-based products with beneficial predatory mites before their integration into IPM programs.

Transgenerational phenotypic plasticity (TGP) allows environmental effects to persist across generations, yet the extent of diet-induced TGP remains incompletely resolved. Prey availability is a key determinant of predator performance in both mass-rearing and field environments, potentially influencing the reliability of pest suppression. Here, we examined how ancestral dietary restriction affects life-history traits in the predatory mite Phytoseiulus persimilis, a widely used biological control agent of the two-spotted spider mite Tetranychus urticae. Founding (F0) and first-generation (F1) individuals were reared under low- or high-prey diets, followed by three generations (F2-F4) under abundant prey to simulate recovery. In F4, individuals from high-prey ancestral lineages exhibited higher survival and larger body size, although size effects were restricted to females. In a second experiment, F5 offspring from crosses manipulating maternal and paternal ancestral diet histories and paternal mating history showed that maternal diet consistently influenced egg size, female developmental duration, and size at maturity. Paternal effects were context-dependent, interacting with maternal lineage and mating history to affect offspring traits. Poor ancestral diet can exert persistent, sex-specific effects on predator performance even after multiple generations of favorable conditions, with maternal influences generally stronger than paternal effects. These findings highlight the complexity of TGP and the importance of considering multigenerational dietary legacies in mass-rearing and field deployment of predatory mites. Optimizing diet during rearing and accounting for ancestral nutritional history may enhance the consistency and effectiveness of biological control programs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effective pest management requires alternative strategies to reduce pesticide use. This study investigates the potential of Mentha suaveolens and Phlomis fruticosa, to act as reservoir plants for the predatory mite Typhlodromus (Anthoseius) recki in tomato crops. Two experiments were conducted in controlled conditions: the first to assess the suitability of these plants for four tomato pests (Tuta absoluta, Trialeurodes vaporariorum, Tetranychus urticae, and T. turkestani) and a second to evaluate the influence of the reservoir plant species, the presence of tetranychid mites on them, and infestation by Aculops lycopersici of nearby tomato plants on predator and tetranychid mites development and dispersal. In experiment 1, neither of the two reservoir plants was favorable to T. absoluta and T. vaporariorum. Mentha suaveolens was favorable to both Tetranychus species, while P. fruticosa was favorable to T. turkestani but much less T. urticae. In the experiment 2, Typhlodromus (A.) recki reproduced and developed on both reservoir plants, even without prey, with higher densities on M. suaveolens. Predators dispersed to tomato plants in all treatments, with consistently higher densities found on tomato plants infested by A. lycopersici. A higher dispersal seems also to better occur when M. suaveolens is the reservoir plant vs. P. fruticosa. The numbers of tetranychid mites remained very low on both reservoir plants and adjacent tomato plants, likely due to efficient predation. These results indicate that both plants can act as reservoirs for T. (A.) recki, even in the absence of prey, but that M suaveolens would be more favorable to adjacent tomato colonization. Further research is needed to optimize predator density and improve reservoir plant configurations for enhanced dispersal.

Neoseiulus cucumeris (Oudemans) is a generalist phytoseiid predatory mite widely used as a biological control agent against phytophagous mites, including tetranychid and tarsonemiid species, as well as thrips and whiteflies. Because identifying a suitable diet is a critical first step for the mass rearing of predatory mites, this study evaluated the effects of several enriched diets of Tyrophagus putrescentiae (Schrank) as a factitious prey (alternative food) on the performance of N. cucumeris. The tested diets included bran (B) as a control; wheat flour + bran (BW); yeast + wheat + bran (BWY); dog food + wheat + bran (BWD); yeast + dog food + bran (BDY); and wheat + yeast + dog food + bran (BWDY). The results showed that the intrinsic rate of increase (r) did not differ significantly among diets compared with the control. However, total lifespan and fecundity of N. cucumeris reared on the enriched diets were higher than those reared on the control and BW diets. The predatory mite was reared on the BDY and BWDY diets for ten consecutive generations. After ten generations, females fed the BDY diet showed significant increases in fecundity, gross reproductive rate (GRR), finite rate of increase (λ), and intrinsic rate of increase (r) relative to G1. In contrast, rearing the predatory mite on the BWDY diet for ten generations resulted in significantly shorter female longevity, adult longevity, and total lifespan compared to those fed BDY at G10. Overall, the BDY diet improved the biological performance of N. cucumeris after ten generations compared with the first generation, while long-term feeding on the BWDY diet maintained stable performance. Although the combination of diets appears more costly than a single diet, the resulting stable performance justifies the additional expense. Therefore, the BWDY diet is considered the most suitable option for the long-term mass rearing of N. cucumeris.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the key pests causing important economic losses in crops. From the predatory mites, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) is used effectively in the biological control of pest mites. On the other hand, diatomaceous earths has a significant potential for controlling numerous arthropod pests including pest mites. Synergistic interactions of different biological control agents such as predatory mites and diatomaceous earths can provide significant benefits in more effective biological control of pest mites. This laboratory study investigated the effect of combined and separate application of the predatory mite, P. persimilis and diatomaceous earth in the biological control of T. urticae. This research is the first to demonstrate the synergistic effect of diatomaceous earths on the efficacy of P. persimilis. After 96 hours, the highest mortality, with 73.19±0.72%, was observed in the combined treatments of P. persimilis and diatomaceous earths. Moreover, significant differences were observed in the fecundity of T. urticae among the test groups. The lowest mean number of eggs per T. urticae female was found in the combined treatment. Simultaneous application of P. persimilis and diatomaceous earths thus turned out to be the most effective treatment against T. urticae. Our laboratory results thus suggest that diatomaceous earth has the potential to enhance the biological control of T. urticae by P. persimilis. Future studies should verify whether these effects translate to greenhouse and field conditions.

The aim of this study was to evaluate the effectiveness of various conventional pesticides in controlling the phytophagous mite Tetranychus urticae Koch compared to a bio-pesticide on eggplant plants during the two consecutive growing seasons of 2024 and 2025 in Fayoum Governorate, Egypt. The compounds used were Gold 1.8% EC (Abamectin 1.8% EC), Gate Fast 12% SC (Thiamethoxam 10% + Abamectin 2%), Azomad 23.8% SC (Imidacloprid 30% + Abamectin 2.8%), and Insect Free (Beauveria bassiana). The impact of these pesticides on predatory mites was also observed. The treatments were evaluated at different day's intervals, and each treatment comprising four replicates. The results showed that Gold had the highest immediate reduction effect (92% and 86%), followed by Gate Fast, Azomad, and Insect Free during the two application seasons, respectively. Gold also recorded the highest overall mean reduction percentage, 80.1%, followed by Gate Fast at 64%, Insect Free at 57.8%, and Azomad at 49.7% in the first season, while these percentages were 78.9%, 61.5%, 58.6%, and 40.4% for Gold, Insect Free, Gate Fast, and Azomad in the second one, respectively. The results also indicated that conventional compounds were more effective during the first spraying season than during the second one, while the bio-pesticide was more effective in the second spraying season than in the first one. Furthermore, the highest average populations of predatory mites (0.47 and 0.66) were observed with the Insect Free treatment, while the lowest average populations (39.0 and 37.0) were recorded with the Gold treatment during the first and second applications, respectively. These findings suggest that the bio-pesticide could effectively control phytophagous mites while remaining safe for beneficial mites, thus confirming its potential as an alternative to conventional chemical pesticides.

The ability of predatory mites to cope with the woven nests of exotic bamboo spider mites

The olive tree (Olea europaea L.) is one of the oldest known cultivated trees worldwide and an iconic species within the Mediterranean Basin. This study evaluated the impact of three bacterial strains, Bacillus subtilis D3, Paenibacillus tundrae M4, and Streptomyces tricolor HM10, on the mortality of the following four mite pests: Oxycenus niloticus, Tegolophus hassani, Aceria olivi, and Tetranychus urticae. B. subtilis D3 confirmed the highest efficacy, causing 91.84–85.36% mortality in laboratory tests and 88.90–84.12% in field trials after five days. In addition, P. tundrae M4 ranked second, achieving 90.49–84.26% mortality in the lab and 87.87–83.81% in the field after one week. S. tricolor HM10 produced 80.06–74.09% mortality in laboratory assays and 76.73–73.36% under the field conditions. Effects on the predatory mites Agistemus exsertus and Amblyseius swirskii were minimal, with mortality ranging from 13.28 to 18.55% in the lab work and 12.46–16.74% in the field experiment. Genome analysis of strain HM10 revealed a biosynthetic gene cluster with predicted terpenes production. Terpenes can cause chemo-osmotic stress and broad membrane-disrupting capabilities. These results highlight the promise of microbial agents for sustainable mite management and provide a foundation for further optimization of bacterial biocontrol strategies.