Tetranychus Urticae Research Articles

Methods to optimize optical sensing of biotic plant stress – combined effects of hyperspectral imaging at night and spatial binning

In spatio-temporal plant monitoring, optical sensing (including hyperspectral imaging), is being deployed to, non-invasively, detect and diagnose plant responses to abiotic and biotic stressors. Early and accurate detection and diagnosis of stressors are key objectives. Level of radiometric repeatability of optical sensing data and ability to accurately detect and diagnose biotic stress are inversely correlated. Accordingly, it may be argued that one of the most significant frontiers and challenges regarding widespread adoption of optical sensing in plant research and crop production hinges on methods to maximize radiometric repeatability. In this study, we acquired hyperspectral optical sensing data at noon and midnight from soybean (Glycine max) and coleus wizard velvet red (Solenostemon scutellarioides) plants with/without experimentally infestation of two-spotted spider mites (Tetranychus urticae). We addressed three questions related to optimization of radiometric repeatability: (1) are reflectance-based plant responses affected by time of optical sensing? (2) if so, are plant responses to two-spotted spider mite infestations (biotic stressor) more pronounced at midnight versus at noon? (3) Is detection of biotic stress enhanced by spatial binning (smoothing) of hyperspectral imaging data? Results from this study provide insight into calculations of radiometric repeatability. Results strongly support claims that acquisition of optical sensing data to detect and characterize stress responses by plants to detect biotic stressors should be performed at night. Moreover, the combination of midnight imaging and spatial binning increased classification accuracies with 29% and 31% for soybean and coleus, respectively. Practical implications of these findings are discussed. Study results are relevant to virtually all applications of optical sensing to detect and diagnose abiotic and biotic stress responses by plants in both controlled environments and in outdoor crop production systems.

Females Guarded by Sneaker Males Experience Higher Predation in the Two‐Spotted Spider Mite

ABSTRACTMales 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.

Comparison of sublethal effects of 3 acaricides on life table parameters of Tetranychus urticae Koch (Acari: Tetranychidae) and Polyphagotarsonemus latus Banks (Acari: Tarsonemidae).

To assess the effects of sublethal concentrations of 3 acaricides-Bifenazate, Etoxazole, and Azocyclotin-on the development and reproduction of Tetranychus urticae Koch (Acari: Tetranychidae) and Polyphagotarsonemus latus Banks. Our results indicated that the LC20 values of Bifenazate, Etoxazole, and Azocyclotin against T. urticae are 3.196, 25.249, and 32.387mg/L, and against P. latus to be 18.058, 4.641, and 13.755mg/L, respectively. Sublethal concentrations of these acaricides significantly impacted the development time, lifespan, and fecundity of both mite species. Among the acaricides, Azocyclotin significantly extended the immature developmental period of T. urticae and P. latus. All acaricides reduced the lifespan and fecundity of both species, with Etoxazole having the most substantial impact on the daily fecundity and reproductive of T. urticae. The intrinsic rates of natural increase (rm) for T. urticae exposed to Bifenazate, Etoxazole, and Azocyclotin were 0.17, -0.04, and 0.20, respectively. For P. latus, the rm values were 0.27, 0.23, and 0.25, respectively. These results suggest that under the exposure of sublethal acaricides, P. latus gained a competitive advantage in population competition. These findings underscore the importance of understanding the differential impacts of acaricides on various mite species to develop effective pest management strategies.

Effect of Sowing Time on Infestation of Sucking Pests in Okra

Okra is highly susceptible to sucking pests like leafhopper, whitefly, and red spider mite, leading to significant yield losses. While farmers rely on insecticides for pest control, excessive use poses risk to the environment. To explore alternatives, a study was conducted at CCS Haryana Agricultural University, Hisar, during kharif 2023 to assess the effect of sowing time on sucking pests infestation in okra. For this, okra was sown on different times i.e., in the 3rd week of May, 1st and 3rd week of June, and 1st and 3rd week of July. The population of leafhopper, whitefly and red spider mite was recorded weekly, starting from the appearance of the pest. The study revealed that leafhopper population in crop sown in the 1st and 3rd week of July was on a par, however, significantly lower than that in other crops. Okra sown in the 1st week of July resulted in significantly lower population of whitefly than rest of the sowing times having population on a par with each other. Mite infestation was significantly lower in crop sown in the 3rd week of July compared to the others. Based on these findings, July appears to be the most suitable time for sowing okra to minimize sucking pests’ infestation.

Tetranychus urticae Koch Biology on Apple Trees

The two-spotted spider mite (Tetranychus urticae Koch) is a polyphagous arthropod herbivore that consumes over 1,100 plant species from 140 distinct plant families, including those producing harmful chemicals in temperate and tropical climates. It is an important pest in greenhouse and field cultivation, causing damage to various crops such as citrus, apples, grapes, tomatoes, peppers, cucumbers, strawberries, maize, and soy. T. urticae ability to spread over agricultural fields and adapt to environmental stressors is linked to its high propensity for mutation, leading to the highest frequency of pesticide resistance among arthropods. The genetic diversity of T. urticae gathered from apple orchards throughout Poland has been studied to investigate potential correlations between molecular variations and the occurrence of resistance to METI-acaricides. Research has shown that an abundance of leaf pubescence on the abaxial leaf surface adversely affects the development of European red mite, two-spotted spider mite, and carmine spider mite. However, due to variations in leaf sizes, tree canopy, tree ages, and the existence of natural enemies, it is impossible to compare data gathered due to variations in leaf sizes, tree canopy, tree ages, and the presence of natural enemies. Pesticide treatments negatively impact fruit plantations' ecosystems, devastating biodiversity, altering the makeup and structure of arthropod populations, and promoting mass reproduction of phytophage mites by displacing certain species with others. The most extensive research has been done on the common spider mite's development of resistance to avermectin group preparations, with some studies showing resistance to multiple acaricides.

RNAi of nuclear receptor E78 inhibits the cuticle formation in the molting process of spider mite, Tetranychus urticae.

The two-spotted spider mite, Tetranychus urticae, is an important pest mite in agriculture worldwide. E78, as a member of the nuclear receptor superfamily and a downstream responsive gene of ecdysteroids, plays a crucial role in regulating physiological behaviors such as development and reproduction in insects. However, its function in mites remains unclear. The aim of this study was to explore how E78 functions in the molting process of spider mites. In this study, reverse transcription quantitative polymerase chain reaction (RT-qPCR) experiments to analyze the expression pattern of TuE78 during the development of Tetranychus urticae, demonstrated that the expression level of TuE78 was higher during the molting state than that after the completion of molting, and it reached a peak expression level when the deutonymph mites entered the molting stage. RNA interference (RNAi)-mediated gene-silencing of TuE78 resulted in 95% deutonymph mite molt failure. A series of analysis under a light microscope, and scanning and transmission electron microscopy revealed that RNAi mites died within the exuvium without ecdysis, and that apolysis had started but the new cuticle was thin and the typical cuticular lamellae were absent, indicating blockage of the post-apolysial processes and explaining molt failure. Hence, transcriptome sequencing confirmed that the expression of cuticle protein and lipid metabolism-related genes was significantly affected after TuE78 silencing. This study demonstrated that TuE78 participates in the molting process of Tetranychus urticae by regulating the post-apolysial processes with the formation of new cuticle and successful ecdysis. This in turn suggests the potential of TuE78 as a target for pest mite control and provides a theoretical basis for further exploration of the molecular regulatory mechanism of spider mite molting. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Bio-Pesticidal Potential of Nanostructured Lipid Carriers Loaded with Thyme and Rosemary Essential Oils against Common Ornamental Flower Pests

The encapsulation of essential oils (EOs) in nanostructured lipid carriers (NLCs) represents a modern and sustainable approach within the agrochemical industry. This research evaluated the colloidal properties and insecticidal activity of NLCs loaded with thyme essential oil (TEO-NLC) and rosemary essential oil (REO-NLC) against three common arthropod pests of ornamental flowers: Frankliniella occidentalis, Myzus persicae, and Tetranychus urticae. Gas chromatography–mass spectrometry (GC-MS) analysis identified the major chemical constituents of the EOs, with TEO exhibiting a thymol chemotype and REO exhibiting an α-pinene chemotype. NLCs were prepared using various homogenization techniques, with high shear homogenization (HSH) providing the optimal particle size, size distribution, and surface electrical charge. A factorial design was employed to evaluate the effects of EO concentration, surfactant concentration, and liquid lipid/solid lipid ratio on the physicochemical properties of the nanosuspensions. The final TEO-NLC formulation had a particle size of 347.8 nm, a polydispersity index of 0.182, a zeta potential of −33.8 mV, an encapsulation efficiency of 71.9%, and a loading capacity of 1.18%. The REO-NLC formulation had a particle size of 288.1 nm, a polydispersity index of 0.188, a zeta potential of −34 mV, an encapsulation efficiency of 80.6%, and a loading capacity of 1.40%. Evaluation of contact toxicity on leaf disks showed that TEO-NLC exhibited moderate insecticidal activity against the western flower thrips and mild acaricidal activity against the two-spotted spider mite, while REO-NLC demonstrated limited effects. These findings indicate that TEO-NLCs show potential as biopesticides for controlling specific pests of ornamental flowers, and further optimization of the administration dosage could significantly enhance their effectiveness.

Explainable olive grove and grapevine pest forecasting through machine learning-based classification and regression

Pests significantly impact agricultural productivity, making early detection crucial for maximizing yields. This paper explores the use of machine learning models to predict olive fly and red spider mite infestations in Andalusia. Four datasets on crop phenology, pest populations, and damage levels were used, with models developed using the Python package H2O, which focuses on interpretability through SHAP values and ICE plots. The results showed high precision in predicting pest outbreaks, particularly for the olive fly, with minimal differences between models using feature selection. In the vineyard dataset, the selection of characteristics improved the performance of the model by reducing the MAE and increasing R2. Explainability techniques identified solar radiation and wind direction as key factors in olive fly predictions, while past pest occurrences and wind velocity were influential for red spider mites, providing farmers with actionable insights for timely pest control.

Oviposition of Panonychus ulmi (Koch, 1936) (Acari: Tetranychidae) in response of conspecific and heterospecific mites cues

This study aimed to assess oviposition of Panonychus ulmi (Koch, 1936) (Acari: Tetranychidae) in response of conspecific and heterospecific mites cues on apple trees (Malus domestica Borkh: Rosaceae). The oviposition of P. ulmi was measured on apple tree leaves with the presence of webs, eggs, and other cues of phytophagous mites (Aculus schlechtendali (Nalepa, 1890) (Acari: Eriophyidae), P. ulmi, Tetranychus urticae Koch, 1936 (Acari: Tetranychidae), and Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae)). The presence of conspecific webs and cues increased the oviposition of P. ulmi, while the presence of A. schlechtendali and T. urticae webs and eggs and A. schlechtendali cues decreased oviposition. The oviposition increases in the presence of conspecifics suggesting that P. ulmi performs better in environments without heterospecific mites. On the other hand, the P. ulmi decreases in oviposition in presence of heterospecific mite cues suggesting a potential competitive displacement of tetranychid by eriophyid mites.

Assessment of Biological Characteristics of Red Spider Mite (Tetranychus urticae) Koch on Brinjal

Red spider mite, Tetranychus urticae Koch passed through five stages viz., egg, larva, protonymph, deutonymph and adult with three short resting stages known as quiescent stages which termed as nymphochrysalis, deutochrysalis and teleiochrysalis. The incubation period of egg was 3.28 ± 1.10 days with 0.13 ± 0.01 mm diameter in size. The average length and breadth of larva, nymphochrysalis, protonymph, deutochrysalis, deutonymphs, teleiochrysalis, adult male and adult female stage were 0.14 ± 0.01 and 0.10 ± 0.01; 0.19 ± 0.01 and 0.12 ± 0.01; 0.20 ± 0.01 and 0.12 ± 0.01; 0.24 ± 0.02 and 0.13 ± 0.01, 0.29 ± 0.02 and 15 ± 0.02, 0.35 ± 0.03 and 0.18 ± 0.01, 0.43 ± 0.04 and 0.19 ± 0.01; and 0.47 ± 0.02 and 0.22 ± 0.01 mm, respectively. The mean duration of male and female larva, nymphochrysalis, protonymph, deutochrysalis, deutonymphs, teleiochrysalis and adult was 2.07 ± 0.73 and 2.36 ± 0.22, 0.58 ± 0.32 and 0.68 ± 0.22, 2.23 ± 0.35 and 2.92 ± 0.81, 0.70 ± 0.35 and 0.76 ± 0.39, 2.12 ± 0.44 and 2.56 ± 0.51, 0.77 ± 0.19 and 0.87 ± 0.37 and 7.12 ± 0.93 and 11.08 ± 0.86 days, respectively. Female of T. urticae occupied 2.48 ± 0.96, 5.32 ± 0.99 and 2.35 ± 0.84 days as pre-oviposition, oviposition and post-oviposition period, respectively. Total life period of male and female was 19.14 ± 2.06 and 23.85 ± 1.65 days, respectively. The average fecundity and hatching percentage were 47.60 ± 6.13 days and 91.11 ± 4.14 per cent, respectively with 1 : 2.50 sex ratio.

How does Neoseiulus californicus McGregor respond to sublethal doses of entomopathogenic fungus Beauveria bassiana (Hyp.: Cordycipitaceae)?

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Prostigmata), is one of the most economically important mite species, mainly controlled by chemical acaricides. Natural enemies have been assessed as reliable alternatives for management of this phytophagous mite. In the current project, demographic characteristics of Neoseiulus californicus McGregor (Acari: Phytoseiidae) to sublethal concentrations (LC10 = 6.76 × 102, LC20 = 8.74 × 103 and LC30 = 55.38 × 103 conidia ml-1) of entomopathogenic fungus, Beauveria bassiana (Bals.) Vuill. TV strain were investigated under laboratory conditions at 25 ± 2°C, 70 ± 5% RH and a photoperiod of 16:8 (L:D) h. Our results indicated that when adult predators were exposed to LC20 and LC30 of B. bassiana, the oviposition period was significantly reduced compared with other treatments. Neoseiulus californicus fecundity was significantly greater in the control (37 eggs) than in LC30 (24 eggs). Life table analysis revealed that the net reproductive rate (R0) declined as the sublethal concentrations of B. bassiana increased. The most striking result to emerge from the data is that not only intrinsic (r); but also, finite rate of increase (λ) was not significantly affected by different concentrations of B. bassiana. Our findings revealed some potential interactions of B. bassiana and N. californicus during their combinations for managing T. urticae that may be helpful for optimising control of this important pest.

Characterization of the Virome Associated with the Ubiquitous Two-Spotted Spider Mite, Tetranychus urticae

Agricultural pests can cause direct damage to crops, including chlorosis, loss of vigor, defoliation, and wilting. In addition, they can also indirectly damage plants, such as by transmitting pathogenic micro-organisms while feeding on plant tissues, affecting the productivity and quality of crops and interfering with agricultural production. Among the known arthropod pests, mites are highly prevalent in global agriculture, particularly those from the Tetranychidae family. The two-spotted spider mite, Tetranychus urticae, is especially notorious, infesting about 1600 plant species and causing significant agricultural losses. Despite its impact on agriculture, the virome of T. urticae is poorly characterized in the literature. This lack of knowledge is concerning, as these mites could potentially transmit plant-infecting viral pathogens, compromising food security and complicating integrated pest management efforts. Our study aimed to characterize the virome of the mite T. urticae by taking advantage of publicly available RNA deep sequencing libraries. A total of 30 libraries were selected, covering a wide range of geographic and sampling conditions. The library selection step included selecting 1 control library from each project in the NCBI SRA database (16 in total), in addition to the 14 unique libraries from a project containing field-collected mites. The analysis was conducted using an integrated de novo virus discovery bioinformatics pipeline developed by our group. This approach revealed 20 viral sequences, including 11 related to new viruses. Through phylogenetic analysis, eight of these were classified into the Nodaviridae, Kitaviridae, Phenuiviridae, Rhabdoviridae, Birnaviridae, and Qinviridae viral families, while three were characterized only at the order level within Picornavirales and Reovirales. The remaining nine viral sequences showed high similarity at the nucleotide level with known viral species, likely representing new strains of previously characterized viruses. Notably, these include the known Bean common mosaic virus (BCMV) and Phaseolus vulgaris alphaendornavirus 1, both of which have significant impacts on bean agriculture. Altogether, our results expand the virome associated with the ubiquitous mite pest T. urticae and highlight its potential role as a transmitter of important plant pathogens. Our data emphasize the importance of continuous virus surveillance for help in the preparedness of future emerging threats.

Acaricidal Efficacy of Abamectin against Tetranychus urticae Populations When Combined with Entomopathogenic Fungi

Tetranychus urticae (Acari: Tetranychidae) is a widespread and serious mite pest that infests tomato plants and causes economic losses worldwide. We investigated the acaricidal efficacy of two isolates of entomopathogenic fungi (EPF) Metarhizium robertsii (WG-7) and Beauveria bassiana (WG-12) alone and in combination with abamectin when applied topically to tomato leaf discs in the laboratory against T. urticae. We also evaluated the establishment and proliferation of T. urticae mite life stages on tomato plants in the greenhouse after application of each of the above treatments. The combination of abamectin with each EPF caused 100% mortality in T. urticae immatures after 2 days while each EPF or abamectin alone caused moderate mortality, not exceeding 74.2% 3 days post-exposure. Complete (100%) mortality of adults was observed after 5 days in leaf discs treated with M. robertsii plus abamectin whereas B. bassiana plus abamectin caused 100% mortality after 7 days. The mean number of eggs, emerged immatures, and adults were significantly reduced on both sides of the leaves (i.e., abaxial and adaxial sides) after using the combined application of M. robertsii or B. bassiana plus abamectin, compared to abamectin alone and controls. Our results reveal that the acaricidal efficacy of abamectin combined with either EPF was significantly better in managing the T. urticae life stages than either treatment alone under greenhouse conditions.

Agroecological Alternatives for Pest and Disease Management in Mexican Lime [Citrus aurantifolia (Christm.) Swingle] Cultivation

agroecological alternatives for the integrated management of recurrent pests in Mexican lime (Citrus aurantifolia); as well as to establish possible synergies with the commercial bioinsecticide. Design/methodology/approach: This experiment was conducted in two phases: 1) visual monitoring and pre-identification of pests and fungal diseases in the Mexican lime crop, and 2) application and evaluation of the effect of application of commercial bioinsecticide (Biocanela) and mineral broths (bordeaux broth and sulfocalcium broth) alone and mixtures. Results: The pests with highest incidence were thrips (Pezothrips kellynus), Asian citrus psyllid (Diaphorina citri), whitefly (Bemisia tabaci), fruit fly (Drosophila melanogaster), and red spider mite (Tetranychus urticae), while the main fungal diseases were sooty mold (Capnodium citri), red algae (Cephaleuros virescens), citrus greasy spot (Mycosphaerella citri), and anthracnose (Colletotrichum acutatum). The mixture of mineral broths with the bioinsecticide Biocanela showed the highest fungicide and insecticide activity, and repellency on various pests and diseases of the Mexican lemon crop. Limitations on study/implications: Generate scientific knowledge regarding to the best agroecological alternatives for the integrated management of citrus pests and diseases that are economically and environmentally profitable. Findings/conclusions: Application of the mixture of sulfocalcium broth and Biocanela showed repellency effectiveness against pests such as thrips (Pezothrips kellyanus), Asian citrus psyllid (Diaphorina citri), whitefly (Bemisia tabaci), and fruit fly (Drosophila melanogaster). Likewise, it was effective against sooty mold (Capnodium citri), red algae (Cephaleuros virescens), and citrus greasy spot (Mycosphaerella citri), while the effect was lighter against anthracnose (Colletotrichum acutatum). Additionally, it induces new, healthy shoots in Mexican lemon trees.

Sustainable Management of Tetranychus urticae and Trialeurodes vaporariorum on Tomato and Cucumber Plants Using Rhamnolipids and Essential Oil-Based Biocontrol Agents.

Rhamnolipids (RLs), biosurfactants produced by Pseudomonas aeruginosa, have gained attention for their potential role in pest management. This study investigated the efficacy of RLs in controlling the two-spotted spider mite (Tetranychus urticae) and the whitefly (Trialeurodes vaporariorum), as well as a novel non-commercial essential oil-based product, Petir Kilat, on cucumber and tomato plants within a controlled greenhouse environment. The RLs were tested at concentrations of 1 mL/L and 2 mL/L, compared to commercial biopesticides including abamectin (ABAMAX) and Beauveria bassiana (NATURALIS). The results indicated that ABAMAX achieved the highest mortality rates for T. urticae and T. vaporariorum, with 100% mortality observed at 7 days. NATURALIS was also highly effective, particularly for whiteflies, though its efficacy declined over time. RLs showed a dose-dependent increase in mortality, with the higher concentration (2 mL/L) yielding more promising results, though not surpassing the commercial products. Petir Kilat, derived from orange essential oils, demonstrated significant control, particularly at higher concentrations, comparable to or exceeding the effectiveness of NATURALIS and ABAMAX in some cases. Statistical analyses revealed significant differences between treatments in most cases (p < 0.05). The findings underscore the potential of RLs and Petir Kilat as components of integrated pest management (IPM) strategies. While RLs are effective, their performance suggests they are best used in combination with other control methods. The study highlights the need for further research to optimize the application of RLs and essential oil-based products to enhance their role in sustainable pest management practices.

Downsizing gum Arabic-based abamectin particles using flash nanoprecipitation method for enhanced pesticide deposition

Pesticides are vital for ensuring crop protection and stable yields, but their low efficiency and eco-unfriendly carriers raise environmental concerns. In this study, abamectin nanopesticides were designed and fabricated using natural polysaccharides [gum arabic (GA)] and a co-stabiliser via flash nanoprecipitation (FNP) method to reduce the size of nanopesticides and enhance their foliar affinity and deposition. Various co-stabilisers were innovatively introduced into the FNP process; the synergy between GA and the co-stabiliser significantly reduced the particle size (111.5 nm), narrowed the size distribution (polydispersity index = 0.078), and enhanced the stability and release performance of the nanopesticides. Importantly, the downsized nanopesticides effectively improved retention on leaf surfaces, reducing pesticide loss. In addition, because of the excellent control capability of the FNP method, the particle size of the nanopesticides could be flexibly adjusted by modifying the flow-based process parameters. Nanopesticides with small sizes demonstrated good control efficacy against Tetranychus urticae, comparable to those of commercial emulsion in water formulations. This study provides an effective approach for enhancing the utilisation efficiency of pesticide droplets by reducing particle size to ensure sustainable agriculture.

Efficiency of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) for controlling three plant-feeding mites on guava trees in Egypt

ABSTRACT Tegolophus guavae (Boczek), Brevipalpus phoenicis (Geijskes), and Tetranychus urticae Koch are plant-feeding mite pests that cause severe damage to the foliage and fruits of guava trees in Egypt. The phytoseiid mite, Neoseiulus californicus (McGregor), was released at three densities (100, 200, and 300 predators/tree). The results indicated that the efficiency of N. californicus was significantly influenced by the release rate. The highest mean reduction percentage after six months of release for T. guavae, B. phoenicis, and T. urticae was, respectively, at 300 predators/tree (64.90, 81.15, and 81.11%) in 2021 and (74.89, 83.76, and 83.07%) in 2022. The mean fruit yields (kg/treatment) in the released plots were substantially greater than those in the control (ranging from 8–16%). The current result suggests that releasing N. californicus is a viable option for biological guava mite pest management.

Effect of variation in plant-emitted volatiles on the infestation behavior of Tetranychus urticae (Acari: Tetranychidae) and Frankliniella occidentalis (Thysanoptera: Thripidae) in strawberry crops.

The two-spotted spider mite (TSSM), Tetranychus urticae Koch, and the Western flower thrips (WFT), Frankliniella occidentalis (Pergande), are pests commonly found in strawberry crops and pose significant challenges to production. However, the specific dynamics of their interactions with both healthy and infested plants remain poorly understood. In this study, we aimed to investigate the attraction of TSSM and WFT to volatile compounds emitted by healthy plants versus those of plants damaged by either or both species. Plant choice bioassays were conducted under varying conditions, including both healthy and those previously damaged by both TSSM and WFT. Additionally, behavioral tests were carried out using a Y-tube olfactometer, with extracts obtained via dynamic aeration from the plants in different states. The results revealed distinct preferences: TSSM exhibited a strong attraction to both healthy plants and those previously infested by their own specifics, whereas WFT showed a higher preference for healthy plants and those damaged by TSSM. Consistent behaviors were observed in the bioassays conducted with plant extracts. This research sheds light on the intricate interactions between strawberry plants and these pests and offers insights into the probable sequence of attack when both pests are present concurrently. The findings are valuable when implementing management strategies for these two pests in strawberry cultivation, considering the order in which they appear in the crop to help mitigate the damage caused by infestation in a more precise manner and order.

"ITAMEC 1.8% Em.K” in Cotton Plant Determination of Biological Effectiveness of Acaricide Against Tetranychus Urticae Pest

Cotton is a crucial crop globally, particularly in Uzbekistan, where its high-quality fibers hold a significant market position. However, cotton faces threats from pests, notably Tetranychus urticae, which can cause up to 40% crop loss if not controlled during the germination period. Despite the use of various agrotechnical measures, effective pest management remains a challenge. This study investigates the acaricide ITAMEC 1.8% em.c. as a control measure against Tetranychus urticae. Field trials were conducted to evaluate the application rates, test results, and biological effectiveness of the drug. Findings suggest that ITAMEC 1.8% em.c. provides significant pest control, offering potential improvements in cotton yield and pest management strategies.

Hyperspectral Imaging and Machine Learning: A Promising Tool for the Early Detection of Tetranychus urticae Koch Infestation in Cotton

Monitoring Tetranychus urticae Koch in cotton crops is challenging due to the vast crop areas and clustered mite attacks, hindering early infestation detection. Hyperspectral imaging offers a solution to such a challenge by capturing detailed spectral information for more accurate pest detection. This study evaluated machine learning models for classifying T. urticae infestation levels in cotton using proximal hyperspectral remote sensing. Leaf reflection data were collected over 21 days, covering various infestation levels: no infestation (0 mites/leaf), low (1–10), medium (11–30), and high (&gt;30). Data were preprocessed, and spectral bands were selected to train six machine learning models, including Random Forest (RF), Principal Component Analysis–Linear Discriminant Analysis (PCA-LDA), Feedforward Neural Network (FNN), Support Vector Machine (SVM), k-Nearest Neighbor (kNN), and Partial Least Squares (PLS). Our analysis identified 31 out of 281 wavelengths in the near-infrared (NIR) region (817–941 nm) that achieved accuracies between 80% and 100% across 21 assessment days using Random Forest and Feedforward Neural Network models to distinguish infestation levels. The PCA loadings highlighted 907.69 nm as the most significant wavelength for differentiating levels of two-spotted mite infestation. These findings are significant for developing novel monitoring methodologies for T. urticae in cotton, offering insights for early detection, potential cost savings in cotton production, and the validation of the spectral signature of T. urticae damage, thus enabling more efficient monitoring methods.