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ABSTRACT Males often employ different reproductive tactics to gain access to females based on their condition and the surrounding environment. Predation risk is expected to have a significant influence on the frequencies of alternative reproductive tactics because these tactics typically differ in activity, which may result in differences in predation rate. In theory, such predation effects can explain the evolution as well as the maintenance of alternative reproductive tactics. Yet, there is little experimental work testing how predation risk affects alternative reproductive tactics. To assess such effects of predation, here we report on experiments with the two‐spotted spider mite Tetranychus urticae. The two‐spotted spider mite is a small arthropod herbivore species, in which males exhibit precopulatory mate guarding by mounting preadult moulting (and hence immobile) females. Two reproductive tactics are observed during mate guarding: The fighting tactic involves attacking other males to drive them away, while the sneaking tactic involves mounting the females and remaining motionless, even when contacted by other males. In this study, we exposed pairs of male and female spider mites to a predatory mite (Phytoseiulus persimilis) and observed their survival and male response to a predator when females were guarded by either fighter or sneaker males. We found that predation risk was not significantly different between fighter and sneaker males. However, the immobile females were more often preyed upon when guarded by sneakers than when guarded by fighters. We attribute this indirect effect of predation risk to the sneakers continuing to mount females even when a predator is nearby. [ABSTRACT FROM AUTHOR]

Spatial and temporal distribution of food resources influences predatory insects' foraging and dispersal behavior. Orius insidiosus (Say) (Hemiptera: Anthocoridae) is a good biological control agent of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), in the strawberry crop and consumes two‐spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae), and pollen as well. Augmentative biological control programs may fail if, following release, predators disperse from the crop. We studied the dispersal of O. insidiosus as a function of pollen availability, density of their main prey WFT, and the presence of the alternative prey TSSM, within and between strawberry plants. We found that O. insidiosus remained on the flowers during the 24 h of the assay. The dispersal of predators to a neighboring flower with thrips was approximately six times greater from a flower without pollen than from a flower with pollen. When TSSM was the only prey available, O. insidiosus colonized the leaves, and its dispersal within the plant was greater. At the plot scale, the predator dispersal from the release plant to other plants also depended on the presence of flowering plants and prey. Our results highlight the importance of flowering plants and pollen availability in enhancing the persistence of O. insidiosus in strawberry plants. Releases of this predator in the strawberry crop should be after the beginning of flowering, even at low WFT densities. [ABSTRACT FROM AUTHOR]

The two-spotted spider mite, Tetranychus urticae Koch (TSSM), is an important cosmopolitan pest of agricultural crops that is often managed in greenhouses by augmentation of predatory mites in combination with acaricides. Here we examined the transgenerational effects of low lethal concentrations of a widely-used acaricide, Oberon Speed® (a combination of spiromesifen and abamectin), on the life history traits and population growth of T. urticae and two of its predators, Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). The concentrations employed corresponded to the LC10, LC20 and LC30 values estimated for TSSM protonymphs 48 h post-exposure in a topical bioassay, which yielded an LC50 value of 207.2 ppm. Parental exposure of TSSM to all three low concentrations increased the total developmental time of progeny; both the LC20 and LC30 treatments reduced adult longevity and number of oviposition days, but only the LC30 treatment increased the preoviposition period. Similarly, both the LC20 and LC30 treatments significantly reduced life table parameters (r, R0, λ, and GRR), and increased generation time (T) and population doubling time (DT). Although maternal exposure to the acaricide had various impacts on progeny life history, A. swirskii was less affected than P. persimilis, suggesting the former species would be more compatible for integration with Oberon Speed® for control of T. urticae in greenhouse vegetable production. [ABSTRACT FROM AUTHOR]

Drought may impact plant–soil biotic interactions in ways that modify aboveground herbivore performance, but the outcomes of such biotic interactions under future climate are not yet clear. We performed a growth chamber experiment to assess how long‐term, drought‐driven changes in belowground communities influence plant growth and herbivore performance using a plant–soil feedback experimental framework. We focussed on two common pasture legumes—lucerne, Medicago sativa L., and white clover, Trifolium repens L. (both Fabaceae)—and foliar herbivores—cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and two‐spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Soil was collected from a field facility where rainfall had been manipulated for 6 years, focussing on treatments representing ambient rainfall and prolonged drought (50% reduction relative to ambient), to consider the effects of biological legacies mediated by the prolonged drought. All soils were sterilized and re‐inoculated to establish the respective home (i.e. where a given plant is cultivated in its own soil) and away (i.e. where a given plant is cultivated in another species' soil) treatments in addition to a sterile control. We found that the relative growth rate (RGR) and relative consumption of larvae were significantly lower on lucerne grown in soil with ambient rainfall legacies conditioned by white clover. Conversely, the RGR of insect larvae was lower on white clover grown in soil with prolonged drought legacies conditioned by lucerne. Two‐spotted spider mite populations and area damage (mm2) were significantly reduced on white clover grown in lucerne‐conditioned soil in drought legacies. The higher number of nodules found on white clover in lucerne‐conditioned soil suggests that root–rhizobia associations may have reduced foliar herbivore performance. Our study provides evidence that foliar herbivores are affected by plant–soil biotic interactions and that prolonged drought may influence aboveground–belowground linkages with potential broader ecosystem impacts. [ABSTRACT FROM AUTHOR]

Soybean is a crucial source of food, protein, and oil worldwide that is facing challenges from biotic stresses. Infestation of Tetranychus urticae Koch (Acari: Tetranychidae) stands out as detrimentally affecting plant growth and grain production. Understanding soybean responses to T. urticae infestation is pivotal for unravelling the dynamics of mite–plant interactions. We evaluated the physiological and molecular responses of soybean plants to mite infestation after 5 and 21 days. We employed visual/microscopy observations of leaf damage, H2O2 accumulation, and lipid peroxidation. Additionally, the impact of mite infestation on shoot length/dry weight, chlorophyll concentration, and development stages was analysed. Proteomic analysis identified differentially abundant proteins (DAPs) after early (5 days) and late (21 days) infestation. Furthermore, GO, KEGG, and protein–protein interaction analyses were performed to understand effects on metabolic pathways. Throughout the analysed period, symptoms of leaf damage, H2O2 accumulation, and lipid peroxidation consistently increased. Mite infestation reduced shoot length/dry weight, chlorophyll concentration, and development stage duration. Proteomics revealed 185 and 266 DAPs after early and late mite infestation, respectively, indicating a complex remodelling of metabolic pathways. Photorespiration, chlorophyll synthesis, amino acid metabolism, and Krebs cycle/energy production were impacted after both early and late infestation. Additionally, specific metabolic pathways were modified only after early or late infestation. This study underscores the detrimental effects of mite infestation on soybean physiology and metabolism. DAPs offer potential in breeding programs for enhanced resistance. Overall, this research highlights the complex nature of soybean response to mite infestation, providing insights for intervention and breeding strategies. [ABSTRACT FROM AUTHOR]

Introduction: Red spider mite (Tetranychus urticae) infestation (SMI) is a detrimental factor for roses grown indoors. Although predatory mite (Neoseiulus californicus) antagonism (PMA) is often utilized to alleviate SMI damage, little is known about the defensive response of greenhouse-grown roses to SMI and the molecular mechanism by which PMA protects roses. Methods: To determine the transcriptome and metabolome responses of roses to SMI and PMA, the leaves of a rose cultivar ("Fairy Zixia/Nightingale") were infested with T. urticae, followed by the introduction of predator mite. Leaf samples were collected at various time points and subjected to transcriptome and metabolome analyses. Results: We found that 24 h of SMI exerted the most changes in the expression of defense-related genes and metabolites in rose leaves. KEGG pathway analysis of differentially expressed genes (DEGs) and metabolites revealed that rose responses to SMI and PMA were primarily enriched in pathways such as sesquiterpenoid and triterpenoid biosynthesis, benzoxazinoid biosynthesis, stilbenoid, diarylheptanoid and gingerol biosynthesis, phytosterol biosynthesis, MAPK signaling pathway, phenylpropanoid biosynthesis, and other pathways associated with resistance to biotic stress. Rose reacted to SMI and PMA by increasing the expression of structural genes and metabolite levels in phytosterol biosynthesis, mevalonate (MVA) pathway, benzoxazinoid biosynthesis, and stilbenoid biosynthesis. In addition, PMA caused a progressive recover from SMI, allowing rose to revert to its normal growth state. PMA restored the expression of 190 essential genes damaged by SMI in rose leaves, including transcription factors DRE1C, BH035, MYB14, EF110, WRKY24, NAC71, and MY108. However, after 144 h of PMA treatment, rose responsiveness to stimulation was diminished, and after 192 h, the metabolic levels of organic acids and lipids were recovered in large measure. Conclusion: In conclusion, our results offered insights on how roses coordinate their transcriptome and metabolome to react to SMI and PMA, therefore shedding light on how roses, T. urticae, and N. californicus interact. [ABSTRACT FROM AUTHOR]

Abstract Plants are attacked by diverse herbivorous pests with different host specializations. While host plant resistance influences pest pressure, how resistance impacts the behaviors of generalist and specialist herbivores, and the relationship to resistance, is less well known. Here, we investigated the short-term (

Abstract Background Production of entomopathogenic fungi on a solid substrate, mostly on rice, is preferred by many producers due to its low technological requirements. Drying may be needed after fermentation to preserve the viability of the conidia until use. This study aimed to introduce some uncomplicated drying techniques and study their effectiveness in terms of drying time and extent, as well as their impact on the quantity of conidia produced and their biological activity. Four techniques were studied, i.e., condensing water vapor (by cooling), desiccant (using NaOH), air drying on a net, and air drying on a solid (impermeable) surface. Results Condensing water vapor and desiccant techniques were the fastest and most efficient, resulting in the lowest moisture content, ranging between 12 and 13%. While drying on a solid surface was the slowest and resulted in the highest moisture content of 32.98%. All of the dried samples yielded a lower quantity of conidia compared to the fresh samples. Samples of condensing water vapor, desiccant, and net techniques yielded approximately a similar quantity of conidia, ranging between 74 and 71% of the yield of the fresh sample. The solid surface sample yielded the lowest quantity of conidia, representing 63.78% of the fresh sample yield. A bioassay test on the mite, Tetranychus urticae Koch (Acari: Tetranychidae), showed that conidia dried via condensing water vapor and desiccant techniques kept their pathogenicity similar to the fresh sample, while samples dried on a net and solid surface significantly lost part of their pathogenicity. Conclusion The condensing water vapor and desiccant techniques were the most efficient regarding the time needed, conidia yield, and pathogenicity. Drying on a solid surface was the least effective regarding the same factors.

Abstract Background Among the Citrus species, lemon (Citrus limon Burm f.) is one of the most affected by the two-spotted spider mite (Tetranychus urticae Koch). Moreover, chemical control is hampered by the mite’s ability to develop genetic resistance against acaricides. In this context, the identification of the genetic basis of the host resistance could represent a sustainable strategy for spider mite control. In the present study, a marker-trait association analysis was performed on a lemon population employing an association mapping approach. An inter-specific full-sib population composed of 109 accessions was phenotyped through a detached-leaf assays performed in modified Huffaker cells. Those individuals, complemented with two inter-specific segregating populations, were genotyped using a target-sequencing approach called SPET (Single Primer Enrichment Technology), the resulting SNPs were employed for the generation of an integrated genetic map. Results The percentage of damaged area in the full-sib population showed a quantitative distribution with values ranging from 0.36 to 9.67%. A total of 47,298 SNPs were selected for an association mapping study and a significant marker linked with resistance to spider mite was detected on linkage group 5. In silico gene annotation of the QTL interval enabled the detection of 13 genes involved in immune response to biotic and abiotic stress. Gene expression analysis showed an over expression of the gene encoding for the ethylene-responsive transcription factor ERF098-like, already characterized in Arabidopsis and in rice for its involvement in defense response. Conclusion The identification of a molecular marker linked to the resistance to spider mite attack can pave the way for the development of marker-assisted breeding plan for the development of novel selection coupling favorable agronomical traits (e.g. fruit quality, yield) with a higher resistance toward the mite.

Plants are attacked by diverse herbivorous pests with different host specializations. While host plant resistance influences pest pressure, how resistance impacts the behaviors of generalist and specialist herbivores, and the relationship to resistance, is less well known. Here, we investigated the short-term (< 1 h) behavioral changes of a generalist herbivore, the two-spotted spider mite (TSM), and a specialist herbivore, the Banks grass mite (BGM), after introduction to no-choice Tanglefoot leaf-arenas (2 × 2 cm) of three maize inbred lines (B73, B75, and B96). The widely-used inbred line B73 is susceptible to spider mites, while B75 and B96 are known to be mite resistant, especially to TSM. Video tracking was used to record TSM and BGM walking, probing, feeding, resting, web-building and travel distance on arenas of each line. Mite oviposition was also recorded after 72 h. B75, a resistant line, decreased the feeding behavior (i.e., time) of both mite species compared to B73 (susceptible control) and B96. Moreover, TSM appeared to be sensitive to both resistant lines (B75 and B96) with reduced oviposition, and increased resting and web-building times compared to susceptible B73. In contrast, the specialist BGM showed no difference in oviposition, resting and web-building time across all maize inbred lines. Our findings of quite broad and short-term responses of TSM to B75 and B96 are consistent with a role for constitutive or rapidly induced plant defenses in maize in conferring TSM resistance. Other mechanisms of plant resistance may be needed, however, for defense against specialists like BGM. [ABSTRACT FROM AUTHOR]

Background: Production of entomopathogenic fungi on a solid substrate, mostly on rice, is preferred by many producers due to its low technological requirements. Drying may be needed after fermentation to preserve the viability of the conidia until use. This study aimed to introduce some uncomplicated drying techniques and study their effectiveness in terms of drying time and extent, as well as their impact on the quantity of conidia produced and their biological activity. Four techniques were studied, i.e., condensing water vapor (by cooling), desiccant (using NaOH), air drying on a net, and air drying on a solid (impermeable) surface. Results: Condensing water vapor and desiccant techniques were the fastest and most efficient, resulting in the lowest moisture content, ranging between 12 and 13%. While drying on a solid surface was the slowest and resulted in the highest moisture content of 32.98%. All of the dried samples yielded a lower quantity of conidia compared to the fresh samples. Samples of condensing water vapor, desiccant, and net techniques yielded approximately a similar quantity of conidia, ranging between 74 and 71% of the yield of the fresh sample. The solid surface sample yielded the lowest quantity of conidia, representing 63.78% of the fresh sample yield. A bioassay test on the mite, Tetranychus urticae Koch (Acari: Tetranychidae), showed that conidia dried via condensing water vapor and desiccant techniques kept their pathogenicity similar to the fresh sample, while samples dried on a net and solid surface significantly lost part of their pathogenicity. Conclusion: The condensing water vapor and desiccant techniques were the most efficient regarding the time needed, conidia yield, and pathogenicity. Drying on a solid surface was the least effective regarding the same factors. [ABSTRACT FROM AUTHOR]

The two-spotted spider mite, T. urticae, is a significant global agricultural pest. It has become highly resistant to numerous pesticides and is incredibly polyphagous. Herein, five pesticides were tested for their ability to control T. urticae: sulfoxaflor + spinetoram, emamectin benzoate, thiamethoxam, spirodiclofen, and etoxazole in the Manfalout and Qusia districts in Assiut Governorate, Egypt during the 2021 and 2022 seasons. The results revealed that all pesticides were effective on T. urticae based on the mean reduction percentage (the ranges were 62.75%- 68.00%) during the 2021 season on cucumber plants in Manflout district. Further, the most potent pesticides in Qusia district were thiamethoxam, spirodiclofen, and emamectin benzoate and the mean reduction percentage were 63.39%, 58.31%, and 56.75%, respectively during the 2021 season. In 2022 season, the most toxic pesticides were thiamethoxam, etoxazole, and emamectin benzoate in Manflout district whereas, in Qusia district, the most powerful pesticides were spirodiclofen, etoxazole, and emamectin benzoate and the mean reduction percentage were 60.00%, 57.67%, and 56.75%, respectively. The tested pesticides are an effective tool that can be used in integrated pest management (IPM) programs against T. urticae on cucumber. [ABSTRACT FROM AUTHOR]

To evaluate the bio-efficacy of different acaricides, an experiment was conducted against Tetranychus urticae (Koch) nourishing Dodi, Leptadenia reticulata (Ret.) Wight & Aruott and the findings revealed that abamectin 1.9 EC @ 0.00038% and spiromesifen 22.9 SC @ 0.02% were superior over other acaricides with a population reduction of 1.93 and 1.95 mites/cm2 leaf, respectively. Likewise, etoxazole 10 SC @ 0.01%, chlorfenapyr 10 SC @ 0.015% and propargite 57 EC @ 0.114% were the next effective treatments as reduced the population of mites at 3.44, 3.83 and 4.38 mites/cm2 leaf. Whereas, the lowest efficacy or highest incidence of mites was recorded in the leaves treated with dimethoate 30 EC @ 0.03% (7.25 mites/cm2 leaf) followed by sulphur 80 WDG @ 0.20% (6.77 mites/cm2 leaf) and ethion 50 EC @ 0.05% (5.82 mites/cm2 leaf). [ABSTRACT FROM AUTHOR]

The two-spotted spider mite (Tetranychus urticae) is a constant threat to greenhouse strawberry production. The application of synthetic acaricides is the main method of controlling T. urticae. However, resistance development to traditional acaricides reduces their efficacy and eventually leads to control failure. It is important for strawberry growers to look for new acaricides and application technologies that can limit the harmfulness of T. urticae in environmentally friendly ways. In the current study, laboratory toxicity tests and field trials were performed to screen high-efficiency acaricides, and then application technologies were improved to enhance the management of T. urticae. In the laboratory toxicity tests, the results showed that the LC50 (median lethal concentration) value of cyetpyrafen, cyenopyrafen, cyflumetofen, bifenazate, abamectin, azocyclotin, pyridaben, spirodiclofen, and etoxazole against adult T. urticae was 0.226, 0.240, 0.415, 3.583, 5.531, 25.58, 39.69, 140.3, and 267.7 mg/L, respectively. In addition, the LC50 value of the nine acaricides against eggs of T. urticae was 0.082, 0.097, 0.931, 18.56, 25.52, 45.61, 36.32, 1.954, and 0.040 mg/L, respectively. The field trial results showed that the best control effect was obtained in cyetpyrafen at 300 mL/ha treatment. Cyetpyrafen was chosen for further application technology tests. In the spray volume tests, the results showed that increasing the spray volume from 900 to 1050 L/ha significantly improved the control of T. urticae. In addition, the results from the spray instrument tests demonstrated that the control effects on T. urticae in the ozone spray treatments were significantly higher than those of the conventional and electrostatic sprays 1 and 3 days after treatment (DAT). Therefore, this study suggested that cyetpyrafen effectively controlled T. urticae both in the laboratory tests and in the field trials. Increasing the spray volume and application of ozone spray significantly improved T. urticae management. [ABSTRACT FROM AUTHOR]

BACKGROUND: The two‐spotted spider mite Tetranychus urticae causes significant damage to ornamental, cotton, sugarcane and horticultural crops in Australia. It has a long history of developing resistance to many acaricides including bifenazate. A mutation in the conserved cd1‐ and ef‐helices of the Qo pocket of cytochrome b is recognized as the primary mechanism of bifenazate resistance. To investigate the resistance mechanisms against bifenazate in Australian two‐spotted spider mite, we sequenced the complete mitochondrion genome of five mite strains including a susceptible and bifenazate‐resistant strain. RESULTS: We identified a novel mutation D252N in the G126S background at cytochrome b being the cause of bifenazate resistance in a bifenazate‐resistant strain, Bram. We validated the role of this mutation combination by reciprocal crosses between a bifenazate resistant and susceptible strain. By doing these crosses we confirmed the pattern of inheritance was maternal. Additionally, mitochondrial heteroplasmy was not observed by single mite genotyping of the mutations in cytb in a known bifenazate‐resistant strain Bram. The phylogenetic analysis with the complete mitochondrion genome sequences revealed that Australian two‐spotted spider mite strains are closely related to the green form of T. urticae found in China. CONCLUSIONS: The novel mutation D252N found in the cytochrome b in the G126S background was revealed to be the main cause of bifenazate resistance in the Australian T. urticae strain Bram. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mycorrhizal plants show enhanced resistance to biotic stresses, but few studies have addressed mycorrhiza‐induced resistance (MIR) against biotic challenges in woody plants, particularly citrus. Here we present a comparative study of two citrus species, Citrus aurantium, which is resistant to Tetranychus urticae, and Citrus reshni, which is highly susceptible to T. urticae. Although both mycorrhizal species are protected in locally infested leaves, they show very distinct responses to MIR. RESULTS: Previous studies have indicated that C. aurantium is insensitive to MIR in systemic tissues and MIR‐triggered antixenosis. Conversely, C. reshni is highly responsive to MIR which triggers local, systemic and indirect defense, and antixenosis against the pest. Transcriptional, hormonal and inhibition assays in C. reshni indicated the regulation of jasmonic acid (JA)‐ and abscisic acid‐dependent responses in MIR. The phytohormone jasmonic acid isoleucine (JA‐Ile) and the JA biosynthesis gene LOX2 are primed at early timepoints. Evidence indicates a metabolic flux from phenylpropanoids to specific flavones that are primed at 24 h post infestation (hpi). MIR also triggers the priming of naringenin in mycorrhizal C. reshni, which shows a strong correlation with several flavones and JA‐Ile that over‐accumulate in mycorrhizal plants. Treatment with an inhibitor of phenylpropanoid biosynthesis C4H enzyme impaired resistance and reduced the symbiosis, demonstrating that phenylpropanoids and derivatives mediate MIR in C. reshni. CONCLUSION: MIR's effectiveness is inversely correlated to basal immunity in different citrus species, and provides multifaceted protection against T. urticae in susceptible C. reshni, activating rapid local and systemic defenses that are mainly regulated by the accumulation of specific flavones and priming of JA‐dependent responses. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Among the Citrus species, lemon (Citrus limon Burm f.) is one of the most affected by the two-spotted spider mite (Tetranychus urticae Koch). Moreover, chemical control is hampered by the mite's ability to develop genetic resistance against acaricides. In this context, the identification of the genetic basis of the host resistance could represent a sustainable strategy for spider mite control. In the present study, a marker-trait association analysis was performed on a lemon population employing an association mapping approach. An inter-specific full-sib population composed of 109 accessions was phenotyped through a detached-leaf assays performed in modified Huffaker cells. Those individuals, complemented with two inter-specific segregating populations, were genotyped using a target-sequencing approach called SPET (Single Primer Enrichment Technology), the resulting SNPs were employed for the generation of an integrated genetic map. Results: The percentage of damaged area in the full-sib population showed a quantitative distribution with values ranging from 0.36 to 9.67%. A total of 47,298 SNPs were selected for an association mapping study and a significant marker linked with resistance to spider mite was detected on linkage group 5. In silico gene annotation of the QTL interval enabled the detection of 13 genes involved in immune response to biotic and abiotic stress. Gene expression analysis showed an over expression of the gene encoding for the ethylene-responsive transcription factor ERF098-like, already characterized in Arabidopsis and in rice for its involvement in defense response. Conclusion: The identification of a molecular marker linked to the resistance to spider mite attack can pave the way for the development of marker-assisted breeding plan for the development of novel selection coupling favorable agronomical traits (e.g. fruit quality, yield) with a higher resistance toward the mite. [ABSTRACT FROM AUTHOR]

Simple Summary: Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is one of the most potent predaceous mites in biological pest management, feeding on phytophagous mites, pollens, and plant exudates. Tetranychus urticae Koch (Acari: Tetranychidae), a global mite, infects many field crops, fruit orchards, and ornamental plants by reducing photosynthesis and feeding on plant cells. This study reveals that the functional response estimates of A. swirskii vary with temperature (14, 18, 22, 26, 30, and 34 ± 1 °C) and prey density. We found that the highest searching efficiency was at 26 °C and that the lowest was at 14 °C. The handling time for each prey item also varies with temperature and prey density. The functional response curves align with the type II functional response model, showing the inverse dependence of temperature and prey density. The predation curves for A. swirskii show a significant difference in the mean numbers of T. urticae consumed at different prey densities and temperatures. This study highlights the relationship between A. swirskii and T. urticae and the importance of temperature and prey density in natural enemies' activities. The findings can help predict A. swirskii behavior and its effectiveness in controlling T. urticae populations. Amblyseius swirskii are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. Tetranychus urticae is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on A. swirskii, a biological control agent for T. urticae. The present results demonstrated the change in the functional response estimates when A. swirskii was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency (a′) showed the highest value (a′ = 0.919) at 26 °C and the lowest value (a′ = 0.751) at 14 °C. The handling time per prey item (Th) for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C (Th = 0.005) and the highest value at 14 °C (Th = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for A. swirskii showed a significant difference between the mean numbers of T. urticae consumed at various prey densities and temperatures, illustrating a relationship between A. swirskii and T. urticae. Therefore, the results of this research may be utilized to forecast the behavior of A. swirskii and its usefulness in controlling T. urticae populations. [ABSTRACT FROM AUTHOR]

Pyrimidifen is an excellent commercial acaricide, but it is not low toxic to mammals. Trifluoroethyl thioether derivatives exhibit excellent bioactivity, and flupentiofenox is the first commercially available trifluoroethyl thioether acaricide. To search for novel pesticides, we conducted research around pyrimidifen and flupentiofenox. By introducing trifluoroethyl thioether and F, Cl, CH3 substituents at different positions on the benzene ring, we successfully introduced trifluoroethyl thioether into the pyrimidine derivatives. Further optimization resulted in compound T7 (HNPC-A188)(5-chloro-6-(difluoromethyl)-N-(2-(2-fluoro-4-methyl-5-((2,2,2-trifluoroethyl)thio)phenoxy)ethyl)pyrimidin-4-amine). HNPC-A188 exhibits excellent acaricidal activity with LC50 values of 0.19 mg/L against Tetranychus urticae, which can be compared with the commercial acaricide cyenopyrafen (LC50 = 0.13 mg/L). [ABSTRACT FROM AUTHOR]

A variety of highly potent derivatives of 2-pyrazoline-5-one, including chromene-3-carbohydrazide 2, 2-thioxothiazole-5-carbohydrazide 3, 2-oxopyridine-3-carbonitriles (4–6), 3-aryl-2-cyanoacrylohydrazide (7, 8), and 3-amino-5-arylpyrazole-4-carbohydrazide (9, 10), were synthesized as pesticide agents using acetohydrazide 1, a versatile and easily obtainable compound. The compounds structures were entirely ascertained utilizing different spectroscopic methods, including Fourier-transform infrared (FTIR), nuclear magnetic resonance spectroscopy, and analysis of elements. In the laboratory, we assessed the impact of nine 2-pyrazoline-5-one derivatives on the fourth larval stage of the cotton leaf worm (Spodoptera littorals), Monacha obstructa, and Tetranychus urticae adults. We used abamectin as the reference compound. The LC50 values of compound 3 for S. littorals, M. obstructa, and T. urticae are 0.90, 0.70, and 0.52 mg a.i./L, respectively. The LC50 values for the same compound for S. littorals, M. obstructa, and T. urticae are 0.80, 0.60, and 0.45 mg a.i./L, respectively. Therefore, it is a remarkably potent compound. Compound 6 exhibited lower levels of danger, as indicated by LC50 values of 1.94, 1.90, and 1.83 mg a.i./L against the three tested pests. Ten days after treatment, all three pests were moderately toxic to the remaining 2-pyrazolin-5-one derivatives, 1, 2, 4, 5, and 7–10. Conversely, the mortality rate of the tested compounds increased when the treated individuals were exposed to high concentrations. These 2-pyrazolin-5-one derivatives are suggested as suitable alternatives and foundational structures for developing novel insecticides.

The damage caused by two-spotted spider mites, and the risks associated with chemical pesticides, including health and environmental risks necessitate the exploration of sustainable pest management methods. Predatory mites, such as Phytoseiulus persimilis, are effective biocontrol agents against pests like the two-spotted spider mite (Tetranychus urticae). Thus, this study aimed to evaluate the suitability of different crops for rearing predatory mites (Phytoseiulus persimilis) and assess their effectiveness in controlling two-spotted spider mites (Tetranychus urticae). Linear regression analysis showed significant effects of selected crops on mite populations across all collection times (Collection 1: F (3, 8) = 22.46, p = 0.0003; Collection 2: F (3, 8) = 11.45, p = 0.0029; and Collection 3: F (3, 8) = 9.17, p = 0.0057). ANOVA showed significant differences in mite counts among the crops (F (3, 32) = 18.06, p

Abstract Piercing sucking pests are destructive to many strategic crops all over the world. Botanical pesticides can be used to control these pests. A new withanolide derivative 3 named sominone A ((20R,22R)-1α,3β,20,27-tetrahydroxywitha-5,24-dienolide) was isolated from the alkaloid fraction of the whole plant of Withania somnifera. In addition, there are three known compounds named withasomine 1, methyl isoferulate 2, and coagulin Q 4 were also isolated. The structures of isolated compounds were identified using different spectroscopic methods such as 1D, 2D NMR, and HRESIMS spectroscopy. The alkaloid fraction and the four isolated compounds were tested for their pesticidal activity against four piercing sucking pests (Aphis craccivora Koch, Bemisia tabaci Gennadius, Nezara viridula Linnaeus, and Tetranychus urticae Koch) that attack many strategic crops under laboratory conditions, along with azadirachtin (Okios 3.2% EC) as a positive control. The results showed that the alkaloid compound (withasomine 1) was the most toxic to A. craccivora, B. tabaci, N. viridula, and T. urticae, with LC50 values of 15.44, 36.61, 85.11, and 128.28 ppm, respectively, compared with the control. Withanolide compounds had moderate effects on all tested pests. Biochemical parameters of six enzymes; α-esterase, β-esterase, chitinase, acetylcholinesterase, glutathione-S-transferase, and peroxidase of A. craccivora were estimated at the LC50 value of the most potent compound, withasomine 1 and the values were 38.83, 72.86, 31.45, 506.4, 2.62, and 251.0, respectively. The results demonstrated that all enzymes activity levels were increased compared with the control except a remarkable inhibition in AChE enzyme level was observed compared with control. Therefore, the alkaloid fraction of W. somnifera is a promising extract that contains many active compounds that can be used as a natural pesticide against many harmful pests in agriculture crops. Graphical Abstract

The two‐spotted spider mite, Tetranychus urticae Koch (Acarina, Tetranychidae), is a notorious agricultural pest known for its high dispersal ability. Understanding the dispersal patterns of T. urticae is crucial for studying its population dynamics and assessing the risk of gene dispersal related to acaricide resistance. We investigated the impact of surrounding landscapes on T. urticae occurrence and detected gene flow between nearby apple orchards. Land use data within 0.2–2 km radius buffers of the orchards were extracted and summarized using principal component analysis. The effects of landscape composition on the occurrence of T. urticae in apple orchards were analyzed using a hierarchical Bayesian model that considers spatial autocorrelation. In addition, we conducted a population genetic analysis on samples collected from five orchards. The results indicate that the best model was one at a 200‐m scale, revealing a positive correlation between forest area ratio and T. urticae occurrence. The population genetic analysis demonstrated distinct genetic structures within T. urticae populations across different orchards. However, we estimated gene flow among some orchards that were geographically close. These findings suggest that T. urticae may migrate from surrounding landscapes, particularly forests, and nearby orchards to apple orchards. These findings have substantial implications for developing control units based on the gene flow range of the two‐spotted spider mite, as well as for assessing the risk of infestation in each orchard. [ABSTRACT FROM AUTHOR]

An investigation was conducted at Kaha Vegetable Research Farm in the Kaliobia Governorate from 2021 to 2023 with an aim to evaluate the performance of six inbred lines of summer squash and their fifteen crosses in both open field and plastic greenhouse conditions. The study spanned two successive summer seasons (2022 and 2023) and focused on assessing horticultural traits and resistance levels to the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Significant variations were observed in the mean performance of all traits among different genotypes. Analysis revealed significant differences in both general (GCA) and specific (SCA) combining abilities for all studied traits, except for the number of days to anthesis of the first female flower, indicating the presence of both additive and non-additive gene effects in traits inheritance. In the plastic greenhouse, genotype P3 exhibited the highest resistance with an average of 10.6 mites per 2 inches², while the cross P2 × P6 showed tolerance with an average of 4.4 mites per 2 inches². This study highlights the potential of new summer squash hybrids with desirable horticultural traits and resistance to the two-spotted spider mite. Additionally, parent 222/2 (P1) demonstrated the best combining ability for all traits, while parents 264 (P5) and 240/3 (P4) were the most effective combiners for total yield. Breeders may leverage these parents for genetic enhancement and the production of hybrids with superior horticultural qualities. Overall, this research provides valuable insights for researchers, breeders and farmers involved in the cultivation, breeding and utilization of summer squash in Egypt. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spider mites were considered secondary pests of walnut production in California, under the control of phytoseiid predators. Due to increased importance as walnut pests in recent decades there is renewed interest in the structure and function of the associated phytoseiid assemblage. In this study we report the results from a 3 year survey of the tetranychid and phytoseiid assemblages in walnut orchards in the Central Valley of California. The survey was conducted to determine the range and dominance of web-spinning Tetranychus species present, to investigate the species richness and dominance of the phytoseiid species present, and to explore whether patterns of variation in the relative abundance of phytoseiid species could be explained by one or more explanatory variables. Tetranychus urticae was the dominant spider mite in all growing regions and years with T. pacificus and T. turkestani also present in orchards in the southern San Joaquin Valley. Phytoseiid species richness declined with latitude among the three walnut growing regions and of the 13 species found Amblyseius similoides, Euseius stipulatus, Galendromus occidentalis and Typhlodromus caudiglans were the most abundant and widespread species present. Mean proportional abundance significantly increased from early (mid May–July) to late (August–mid October) season and from southern to northern growing regions for Type II and IV predators, but significantly decreased from early to late season and from southern to northern growing regions for Type III predators. The mean proportional abundance of Type II predators, particularly G. occidentalis, significantly increased and that of Type III predators significantly decreased with mean Tetranychus density in individual orchards. The current survey provides a more in-depth analysis of mite assemblages in walnut orchards in California and can be used to better inform adaptive management strategies for integrated mite management in the future. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Harran Journal of Agricultural & Food Science is the property of Harran University, Faculty of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The biology of Tetranychus urticae Koch on lady's finger was undertaken at Laboratory, Department of Entomology, Chimanbhai Patel College of Agriculture (CPCA), Sardarkrushinagar, Dantiwada Agricultural University, Sardarkrushinagar, Gujarat, India during summer 2022. Mite, T. urticae has five life stages viz., egg, larva, protonymph, deutonymph and adult with three quiescent stages called as nymphochryasalis, deutochrysalis and teleiochrysalis. The incubation period of egg was 3.40±1.03 days. The respective period of larva, nymphochryasalis, protonymph, deutochrysalis, deutonymph, teleiochrysalis, total development and adult were: 1.73±0.78, 0.60±0.30, 2.53±0.68, 0.57±0.27, 2.13±0.73, 0.72±0.21, 8.76±1.40 and 11.93 ±1.08 days, respectively, in the case of male while they were 2.70±0.75, 0.64±0.21, 2.86±0.81, 0.70±0.29, 2.66±0.66, 0.85±0.26, 11.86±1.88 and 14.56±1.07 days, respectively, in case of female mite. Female of T. urticae occupied 2.86±0.81, 7.26±1.43 and 2.26±0.69 days as pre-oviposition, oviposition and post-oviposition period. Total life span of male and female were 21.76±2.38 and 26.46±2.20 days. [ABSTRACT FROM AUTHOR]

Tetranychus urticae, a prominent pest mite in strawberry and vegetable cultivation in China, has developed escalating resistance due to extensive chemical pesticide application. Consequently, there is an urgent need to identify safe and efficacious methods to reduce resistance development. In this study, 38 commercially available plant essential oils (EOs) were screened for their acaricidal potential and ability to inhibit oviposition. The findings revealed that 13 EOs exhibited notable acaricidal activity, with lemon EO demonstrating the highest toxicity, followed by sage, patchouli, frankincense, lemongrass, palmarosa, and oregano EOs. In addition, 18 EOs displayed significant inhibitory effects on oviposition, with lemon EO exhibiting the highest inhibition rate (99.15%) and inhibition index (0.98). Subsequently, sage, frankincense, clove, lemongrass, oregano, patchouli, myrrh, black pepper, palmarosa, and geranium EOs also showed inhibition rates exceeding 50%. Despite black pepper, clove, myrrh, and oregano EOs demonstrating relatively low toxicity against T. urticae, they exhibited heightened efficacy in inhibiting oviposition and suppressing population expansion. This study conducted a comparative assessment of the acaricidal and oviposition inhibition activities of EOs and their principal constituents, thus providing a theoretical basis for the development of botanical acaricides against T. urticae. [ABSTRACT FROM AUTHOR]

Piercing sucking pests are destructive to many strategic crops all over the world. Botanical pesticides can be used to control these pests. A new withanolide derivative 3 named sominone A ((20R,22R)-1α,3β,20,27-tetrahydroxywitha-5,24-dienolide) was isolated from the alkaloid fraction of the whole plant of Withania somnifera. In addition, there are three known compounds named withasomine 1, methyl isoferulate 2, and coagulin Q 4 were also isolated. The structures of isolated compounds were identified using different spectroscopic methods such as 1D, 2D NMR, and HRESIMS spectroscopy. The alkaloid fraction and the four isolated compounds were tested for their pesticidal activity against four piercing sucking pests (Aphis craccivora Koch, Bemisia tabaci Gennadius, Nezara viridula Linnaeus, and Tetranychus urticae Koch) that attack many strategic crops under laboratory conditions, along with azadirachtin (Okios 3.2% EC) as a positive control. The results showed that the alkaloid compound (withasomine 1) was the most toxic to A. craccivora, B. tabaci, N. viridula, and T. urticae, with LC50 values of 15.44, 36.61, 85.11, and 128.28 ppm, respectively, compared with the control. Withanolide compounds had moderate effects on all tested pests. Biochemical parameters of six enzymes; α-esterase, β-esterase, chitinase, acetylcholinesterase, glutathione-S-transferase, and peroxidase of A. craccivora were estimated at the LC50 value of the most potent compound, withasomine 1 and the values were 38.83, 72.86, 31.45, 506.4, 2.62, and 251.0, respectively. The results demonstrated that all enzymes activity levels were increased compared with the control except a remarkable inhibition in AChE enzyme level was observed compared with control. Therefore, the alkaloid fraction of W. somnifera is a promising extract that contains many active compounds that can be used as a natural pesticide against many harmful pests in agriculture crops. [ABSTRACT FROM AUTHOR]

Key message: NOI10 and NOI11 are two RIN4-like/NOI proteins that participate in the immune response of the Arabidopsis plant and affect the RIN4-regulated mechanisms involving the R-proteins RPM1 and RPS2. The immune response in plants depends on the regulation of signaling pathways triggered by pathogens and herbivores. RIN4, a protein of the RIN4-like/NOI family, is considered to be a central immune signal in the interactions of plants and pathogens. In Arabidopsis thaliana, four of the 15 members of the RIN4-like/NOI family (NOI3, NOI5, NOI10, and NOI11) were induced in response to the plant herbivore Tetranychus urticae. While overexpressing NOI10 and NOI11 plants did not affect mite performance, opposite callose accumulation patterns were observed when compared to RIN4 overexpressing plants. In vitro and in vivo analyses demonstrated the interaction of NOI10 and NOI11 with the RIN4 interactors RPM1, RPS2, and RIPK, suggesting a role in the context of the RIN4-regulated immune response. Transient expression experiments in Nicotiana benthamiana evidenced that NOI10 and NOI11 differed from RIN4 in their functionality. Furthermore, overexpressing NOI10 and NOI11 plants had significant differences in susceptibility with WT and overexpressing RIN4 plants when challenged with Pseudomonas syringae bacteria expressing the AvrRpt2 or the AvrRpm1 effectors. These results demonstrate the participation of NOI10 and NOI11 in the RIN4-mediated pathway. Whereas RIN4 is considered a guardee protein, NOI10 and NOI11 could act as decoys to modulate the concerted activity of effectors and R-proteins. [ABSTRACT FROM AUTHOR]

Our study was conducted to determine how red spider mite infection affected tomato leaves' histological characters and biochemical attributes. Tetranychus urticae infection impacts four tomato hybrids, 09, Supper-gekal, Super strain B, and Blatenium on particular histological traits and biochemical elements. Thirty leaf samples of each infested and uninfested plant were collected, transported to the lab, and prepared for histological and biochemical analysis. As a result of infestation, the thickness µm of epidermis and parenchyma cells of tomato leaves in all examined hybrids was influenced, it decreased for upper and lower epidermis cells and conversely, it increased in the case of parenchyma cells compared with uninfested tomato leaves as a control. In all tested hybrids, mite infestation lowered photosynthetic pigments such as chlorophyll a, b, and total carotenoids in addition to the indicators of photosynthetic activity. The percentage loss of photosynthetic pigments of the 09 hybrid was affected more than the other three hybrids recording 37.47, 23.99, and 34.27% of chlorophyll a, b, and total carotenoids. Some organic substances were evaluated in 09 hybrids including lipids, carbohydrates, proteins, flavonoids, phenols, and alkaloids plus, nutrients such as total nitrogen, potassium, and phosphorus. Results revealed that mite infestation affected all tested biochemical components. Lipids, proteins, phenols, and alkaloids were generally higher in infested leaves (1.69, 18.84, 1.211, and 0.94 g/100g), respectively than in uninfested leaves (1.53, 18.66, 0.963, and 0.68 g/100g). Flavonoids and carbohydrates were significantly reduced in infested leaves, measuring 19.38 and 0.042 (g/100 g), respectively as opposed to 21.78 and 0.084 (g/100g) in uninfested leaves. [ABSTRACT FROM AUTHOR]

Abstract Background Plants have acquired a repertoire of mechanisms to combat biotic stressors, which may vary depending on the feeding strategies of herbivores and the plant species. Hormonal regulation crucially modulates this malleable defense response. Jasmonic acid (JA) and salicylic acid (SA) stand out as pivotal regulators of defense, while other hormones like abscisic acid (ABA), ethylene (ET), gibberellic acid (GA) or auxin also play a role in modulating plant-pest interactions. The plant defense response has been described to elicit effects in distal tissues, whereby aboveground herbivory can influence belowground response, and vice versa. This impact on distal tissues may be contingent upon the feeding guild, even affecting both the recovery of infested tissues and those that have not suffered active infestation. Results To study how phytophagous with distinct feeding strategies may differently trigger the plant defense response during and after infestation in both infested and distal tissues, Arabidopsis thaliana L. rosettes were infested separately with the chewing herbivore Pieris brassicae L. and the piercing-sucker Tetranychus urticae Koch. Moderate infestation conditions were selected for both pests, though no quantitative control of damage levels was carried out. Feeding mode did distinctly influence the transcriptomic response of the plant under these conditions. Though overall affected processes were similar under either infestation, their magnitude differed significantly. Plants infested with P. brassicae exhibited a short-term response, involving stress-related genes, JA and ABA regulation and suppressing growth-related genes. In contrast, T. urticae elicited a longer transcriptomic response in plants, albeit with a lower degree of differential expression, in particular influencing SA regulation. These distinct defense responses transcended beyond infestation and through the roots, where hormonal response, flavonoid regulation or cell wall reorganization were differentially affected. Conclusion These outcomes confirm that the existent divergent transcriptomic responses elicited by herbivores employing distinct feeding strategies possess the capacity to extend beyond infestation and even affect tissues that have not been directly infested. This remarks the importance of considering the entire plant’s response to localized biotic stresses.

The study sought to ascertain spider mite prevalence, infestation, and identification and to assess the response of potato genotypes. In 2022, this pest was only observed on some genotypes in December. In late January, an infestation, incidence, and severity increased from 10 to 13 genotypes on potato tuber stocks stored for irrigation experiments. Those genotypes were planted in irrigated fields, and the sprouted tuber losses ranged from 12.5% to 100% and up to 15.38% in the 2022 and 2023 records, respectively. Following this, spider mites, often known as two-spotted spider mites (TSSM) or Tetranychus urticae, were identified. This is the first time a potato sprout infestation has been recorded in Ethiopia. The two-spotted spider mites damaged the tubers quantitatively by sucking the moisture of sprouts up to the 5th grade, with 97 and >75% infestation levels, incidence, and severity, respectively. The pest grows very rapidly and hastens the drying of sprouted tuber leaves. Some genotypes were resistant to TSSM and recovered after the sprouts were infected and dried, which were treated with pesticides in 2023. The typical agricultural insecticides were ineffective in controlling the pest in the first year, and a Profenofos was applied in the second year. Thus, seed tubers are the main production limit unless appropriate research efforts are undertaken and management techniques are created.

The population dynamics of Tetranychus urticae (two-spotted spider mite – TSSM) are influenced by environmental factors, which were investigated to identify methods limiting the development and harmfulness of this pest. This paper presents findings from a laboratory study on the effect of spraying with water-based extracts of Mentha piperita and Tagetes patula plants on the growth rate of TSSM larvae and nymphs. The time required for the transformation of the larvae into protonymphs was longer for T. patula water- based extracts than extracts from M. piperita. Differences in the time of transformation from the nymphal stage to adult TSSM were also observed depending on the plant waterbased extracts, their concentration, and the host plant on which nymphs were developing. The use of 100 g ∙ l-1 French marigold extract was associated with longer transformation time of nymphs on discs of pea leaves than all tested concentrations of French marigold extract applied to sugar beet leaves. Ten percent of the extracts from peppermint plants had a stronger limiting effect on TSSM nymphs on pea leaves than on bean or sugar beet leaves.

Background: Plants have acquired a repertoire of mechanisms to combat biotic stressors, which may vary depending on the feeding strategies of herbivores and the plant species. Hormonal regulation crucially modulates this malleable defense response. Jasmonic acid (JA) and salicylic acid (SA) stand out as pivotal regulators of defense, while other hormones like abscisic acid (ABA), ethylene (ET), gibberellic acid (GA) or auxin also play a role in modulating plant-pest interactions. The plant defense response has been described to elicit effects in distal tissues, whereby aboveground herbivory can influence belowground response, and vice versa. This impact on distal tissues may be contingent upon the feeding guild, even affecting both the recovery of infested tissues and those that have not suffered active infestation. Results: To study how phytophagous with distinct feeding strategies may differently trigger the plant defense response during and after infestation in both infested and distal tissues, Arabidopsis thaliana L. rosettes were infested separately with the chewing herbivore Pieris brassicae L. and the piercing-sucker Tetranychus urticae Koch. Moderate infestation conditions were selected for both pests, though no quantitative control of damage levels was carried out. Feeding mode did distinctly influence the transcriptomic response of the plant under these conditions. Though overall affected processes were similar under either infestation, their magnitude differed significantly. Plants infested with P. brassicae exhibited a short-term response, involving stress-related genes, JA and ABA regulation and suppressing growth-related genes. In contrast, T. urticae elicited a longer transcriptomic response in plants, albeit with a lower degree of differential expression, in particular influencing SA regulation. These distinct defense responses transcended beyond infestation and through the roots, where hormonal response, flavonoid regulation or cell wall reorganization were differentially affected. Conclusion: These outcomes confirm that the existent divergent transcriptomic responses elicited by herbivores employing distinct feeding strategies possess the capacity to extend beyond infestation and even affect tissues that have not been directly infested. This remarks the importance of considering the entire plant's response to localized biotic stresses. [ABSTRACT FROM AUTHOR]

The use of chemical pesticides to control two spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) in various crops has resulted in the development of various problems viz., residues in sprayed crop, pest resistance, pest resurgence and environmental pollution. For an effective alternate environmentally safe management tactic, the microbial biorationals constitute an important tool. In the present study, entomopathogenic fungi (EPF) and botanical pesticides were tested at different concentrations for the management of eggs and other active stages of T. urticae infesting parthenocarpic cucumber grown under poly-net house. Among these biorationals, spraying of Neem Baan at 10 and 15 ml/l resulted in significantly higher level of reduction in TSSM population (88.5 to 91.8% in egg and 86.6 to 90.9% in active stage of mites after 3rd spray, respectively) than with EPFs. Among the EPFs, Lecanicillium lecanii (Zimmerman) Viegas and Beauveria bassiana Balsamo (Vuillemin) [(at 10 & 15 ml/l (82.0 to 87.0% in egg and 79.2 to 84.1% in active stage of mites)] was found to be more effective than Metarhizium anisopliae (Metschnikoff) Sorokin [(at 10 & 15 ml/l (77.0 to 82.4% in egg and 76.4 to 80.4% in active stage of mites after third spray, respectively)] in reducing different life stages of T. urticae on cucumber. Significantly higher yields of cucumber were recorded from plot treated with Neem Baan at 10 and 15 ml/l (2350.7 to 2437.3 g/ plant) were used. As Neem Baan 1% increased growth and yield of cucumber by controlling T. urticae, effectively, it can act as a good alternative for the chemical pesticide which in most instances leads to residues, pest resistance and pest resurgence problems. [ABSTRACT FROM AUTHOR]

Australian ports are continuously exposed to exotic and invasive mite and insect species associated with imported fresh produce. Much effort is focused on preventing the exotic species from entering Australia by product fumigation or destruction in a timely manner. However, quarantine intercepts of invasive species may contain unwanted resistance to pesticides or carry viruses that can undermine Australian agricultural sustainability. We examined pesticide resistance status in 1275 Tetranychus urticae samples from quarantine intercepts from the Department of Agriculture, Fisheries and Forestry originating from some 29 countries spread over 6 main continents (Africa [4], Asia [12], Europe [3], North America [2], Oceania [4] and South America [4]). We used a high‐throughput multiamplicon sequencing platform to screen major target‐site mutations that cause acaricide resistance in T. urticae. These included G119S, A201S, T280A, G328A and F331Y (Ace‐1) associated with mode of action (MoA) 1 insecticide (organophosphates and carbamates); M918, L925I, L1014F and F1538I (VGSC) associated with MoA 3 insecticide (pyrethroids); G314D (GluCl1) associated with MoA 6 insecticide (avermectins and milbemycins); and finally, H92R (PSST) associated with MoA 21 insecticide (fenpyroximate, pyridaben and tebufenpyrad). The results revealed that four known mutations (G119S, T280A, G328A and F331W) were abundant in the quarantine samples including those from Norfolk Island and New Zealand. The mutations L1024V, F1538I and L925V (VGSC) associated with pyrethroid resistance were widespread through many samples, but the super Kdr mutation M918 was not detected. Similarly, H92R (PSST) that causes resistance to fenpyroximate, pyridaben and tebufenpyrad was found in most of the T. urticae intercept samples. We conclude that resistance alleles entering Australia through quarantine intercepts are common, suggesting that unwanted or rare alleles could enter Australia via this route. However, exotic quarantine breaches carrying such alleles remain of most serious concern. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tetranychus urticae is a hard‐to‐control pest of greenhouse strawberry production. Nighttime ultraviolet B (UV‐B) radiation using light reflection sheets (LRS) has been applied as a physical method to control T. urticae through direct ovicidal effects (the UV method). However, because strawberry leaves grow more densely, UV‐B radiation fails to reach the lower leaf surfaces inhabited by spider mites; therefore, a complementary method is required. We propose the supplemental application of phytoseiid mites in greenhouse strawberry production. We evaluated the control effects of UV‐B irradiation, phytoseiid mite application and their combined use. The effects of UV‐B irradiation on the degree of overlap relative to the independent distributions (ω) between predators and prey were also analyzed. RESULTS: The UV method alone maintained low T. urticae density levels from November to February; however, mite populations increased from March onward. Phytoseiid mite application in January and February without UV‐B irradiation resulted in a temporary increase in spider mites in March and/or April. By contrast, combined application of the UV method and phytoseiid mites had a greater control effect during the strawberry growing season. The ω values were higher for the UV method compared with no UV‐B irradiation, suggesting that UV‐B irradiation increased phytoseiid mite foraging rates. CONCLUSION: The release of phytoseiid mites compensated for the shortcomings of the UV method, and UV‐B irradiation promoted predation by phytoseiid mites by increasing the behavioral numerical response. Consequently, combined application of UV‐B irradiation and phytoseiid mites is optimal for T. urticae control in greenhouse strawberry production. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: The two-spotted spider mite Tetranychus urticae and its interactions with fungi, notably Beauveria bassiana, on common bean plants were the main subjects of this study. The mite's life cycle on untreated and endophyte-colonized plants was examined using the age-stage, two-sex life table hypothesis. The findings indicated that mites reared on untreated plants had shorter developmental stages and higher fecundity than those on colonized plants. Furthermore, mites on untreated plants displayed a higher intrinsic rate of increase and net reproductive rate. The study also revealed that fungal endophyte colonization negatively affected mite growth, adult lifespan, fecundity, reproductive rate, and the intrinsic rate of increase. The findings point to a possible application of entomopathogenic fungal endophytes in host plant resistance programs for future integrated pest control. Tetranychus urticae is a highly polyphagous and global pest. Spider mites primarily feed on the underside of leaves, resulting in decreased photosynthesis, nutritional loss, and the development of chlorotic patches. We investigated the life tables of the two-spotted spider mite T. urticae on fungal endophyte Beauveria bassiana colonized and untreated plants of the common Phaseolus vulgaris L., a bean plant. Based on the age-stage, two-sex life table theory, data were evaluated. The mites raised on untreated plants had protonymphs, deutonymphs, and total pre-adult stage durations that were considerably shorter (1.76, 2.14, and 9.77 d, respectively) than the mites raised on plants that had been colonized (2.02, 2.45, and 10.49 d, respectively). The fecundity (F) varied from 28.01 eggs per female of colonized plants to 57.67 eggs per female of endophyte-untreated plants. The net reproductive rate (R0) in the plants with and without endophytes was 19.26 and 42.53 brood, respectively. The untreated plants had an intrinsic rate of increase (rm) of 0.245 days as opposed to the colonized plants, which had an r of 0.196 days and a finite rate of increase (λ) (1.27 and 1.21, respectively). Population forecasts based on a two-sex, age-stage life table demonstrated the dynamism and variability of the stage structure. Furthermore, the colonization of B. bassiana had a negative impact on the growth and development of T. urticae. It lowered the adult mite life span, female fecundity, net reproduction rate, and intrinsic growth rate. We propose that future research should better use entomopathogenic fungal endophytes to understand host plant resistance strategies in integrated pest management. [ABSTRACT FROM AUTHOR]

The two-spotted spider mite Tetranychus urticae Koch, the date palm dust mite Oligonychus afrasiaticus (McGregor), and the citrus brown mite Eutetranychus orientalis (Klein) of family Tetranychidae are key pests of fruit trees, field crops, and ornamentals that cause significant yield losses. The purpose of this research was to assess the effect of three constant temperatures (22, 27, and 32 °C) on the developmental time, life-table parameters, and consumption rate of the predatory beetle Stethorus gilvifrons (Mulsant) on maize leaf disks with T. urticae, O. afrasiaticus, and E. orientalis as food. The results indicated a significant difference between the three different temperatures and prey types. The shortest developmental time was recorded on T. urticae (9.30 and 10.10 days) at 32 °C, while the longest was on E. orientalis (23.34 and 22.50) at 22 °C for females and males, respectively. The shortest female longevity was on E. orientalis (21.14 days) at 32 °C, and the longest was 39.12 days on T. urticae at 22 °C. The fecundity increased as temperature increased, from 114.6 eggs with a daily rate of 3.81 eggs per female/day at 22 °C to 235.0 eggs with a daily rate of 10.78 eggs per female/day at 32 °C on T. urticae. The highest net reproductive rate (R0), intrinsic rate of natural increase (rm), and finite rate of increase (λ) were recorded at 32 °C, whereas the lowest values were recorded at 22 °C when predatory beetles S. gilvifrons were fed on three prey diets. Gross reproduction rate (GRR) recorded the highest value (132.8 offspring/individual) when fed on T. urticae at 32 °C and the lowest value (55.30 offspring/individual) when fed on E. orientalis at 22 °C. The highest consumption rate of adult males and females was 226.8 and 245.4 individuals when fed on O. afrasiaticus at 22 °C, while the lowest was 123.6 and 133.8 individuals on E. orientalis at 32 °C. Thus, the results obtained here revealed that temperature and prey diets influence the developmental rate and reproduction of S. gilvifrons. Additionally, T. urticae is better for mass rearing of S. gilvifrons than O. afrasiaticus and E. orientalis as food. [ABSTRACT FROM AUTHOR]