Species Of Phytoseiid Mites Research Articles

Selectivity and molecular stress responses to classical and botanical acaricides in the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae).

Acaricide application remains an integral component of integrated pest management (IPM) for the two-spotted spider mite Tetranychus urticae. Species and strains of phytoseiid predatory mites vary significantly in their response to acaricides. For the success of IPM, it is imperative to identify the determinants of selectivity and molecular stress responses of acaricides in predatory mites. The three classical acaricides bifenazate, cyflumetofen, and fenbutatin oxide did not affect the survival and fecundity of Phytoseiulus persimilis regardless of the route of exposure. Selectivity of the orange oil and terpenoid blend-based botanical acaricides was low via a combination of direct exposure, acaricide-laced diet, and residual exposure but improved when limiting exposure only to diet. To gain insights into the molecular stress responses, the transcriptome of P. persimilis was assembled. Subsequent gene expression analysis of predatory mites orally exposed to fenbutatin oxide and orange oil yielded only a limited xenobiotic stress response. In contrast, P. persimilis exhibited target-site resistance mutations, including I260M in SdhB, I1017M in CHS1, and kdr and super-kdr in VGSC. Extending the screen using available Phytoseiidae sequences uncovered I136T, S141F in cytb, G119S in AChE, and A2083V in ACC, well-known target-sites of acaricides. Selectivity of the tested botanical acaricides to P. persimilis was low but could be enhanced by restricting exposure to a single route. Differential gene expression analysis did not show a robust induced stress response after sublethal exposure. In contrast, this study uncovered target-site mutations that may help to explain the physiological selectivity of several classical acaricides to phytoseiid predators.

Description of eleven new species of phytoseiid mites (Acari: Mesostigmata) from Meghalaya state, north eastern India

A survey was done in the state of Meghalaya, India covering East Khasi Hills, West Jaintia Hills and Ri-Bhoi districts during May to July, 2019. During the survey 350 specimens were collected from which 11 new species are describedAmblyseius azaliae sp. nov., Amblyseius meghalayensis sp. nov., Euseius fascae sp. nov., Euseius dwakiensis sp. nov., Okiseius jainticus sp. nov., Okiseius unisetatus sp. nov., Phytoseius clavus sp. nov., Phytoseius aonlae sp. nov., Typhlodromus (Anthoseius) barapanicus sp. nov., Typhlodromus (Anthoseius) campana sp. nov., and Typhlodromus (Anthoseius) cherrapunjiensis sp. nov.

Phytoseiid mites (Acari: Mesostigmata) from Apulia (Southern Italy), with a key to the species reported from Italy

ABSTRACT The objective of this paper is to provide a taxonomic appraisal of the phytoseiids mainly from Apulia, Italy, through the examination of 1055 specimens collected in the areas of that district. Reports of occasional collection in Basilicata and Molise areas are also listed (16 specimens). The mite specimens were collected on the main cultivated and ornamental plants, and on spontaneous plants as well. Complementing the morphological characterization of the species collected is provided. This is the first wide report survey on the phytoseiid fauna in Apulian territories. This study reports on nine new records of Phytoseiidae for Apulia region (Southern Italy). Typhlodromus (Typhlodromus) exhilaratus Ragusa was the most frequent or abundants species sampled. Also, some other species, i.e. Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot, were collected and are potential taxa for biocontrol. In addition, a dichotomous key to separate phytoseiid mite species listed from Italy was provided.

Re-description of seven predatory mite species of family Phytoseiidae (Acari: Mesostigmata) sourced from Florida citrus groves.

Predatory mites in the family Phytoseiidae (Acari: Mesostigmata) are of great importance as biological control agents of pest mites and other arthropods. Correct identification of species is crucial to implement effective biological control of target pests. Here, we provide re-descriptions of seven phytoseiid mite species collected from citrus orchards in Florida. The several important morphological features including dorsal setae lengths, dorsal solenostomes, shape of calyx of spermatheca, chelicera dentition, measurements, and shape of macrosetae on legs currently used to discriminate phytoseiid species were missing in the original descriptions and re-descriptions of these species. Additionally, we observed the presence of a previously unnoted taxonomically important character on Proprioseius meridionalis Chant. Therefore, the re-description was essential for further diagnosis of this species. Accordingly, the validity of the presence/absence of this structure as a diagnostic character to separate species groups in the genus Proprioseius should be re-considered. Furthermore, Typhlodromalus peregrinus, a species for which a series of morphological variations are reported in previous descriptions, is re-described and illustrated from Clermont, Florida, a location very close (10 km) to its type location (Minneola), and the leaves of type host citrus. The macrosetae StIV was knobbed apically in all our specimens of T. peregrinus indicating invalidity of sharp-pointed or knobbed StIV to separate this species from a closely related species, T. aripo De Leon. These re-descriptions and species are important to utilizing authentic and promising candidates for biological control.

Molecular variation of the cytochrome b DNA and protein sequences in Phytoseiulus macropilis and P. persimilis (Acari: Phytoseiidae) reflect population differentiation.

Several phytoseiid mite species are important natural enemies used in biological control strategies. In the present study, Cytb mtDNA sequences of various populations of two species, Phytoseiulus macropolis and P. persimilis, were compared to determine whether the specimens collected in Brazil could belong to P. persimilis as this latter species is reported in South America but not in Brazil. The Cytb marker was used because of its high evolution rate, assumed to capture intraspecific variation. No overlap between intra- and interspecific distances was observed but the distances were quite low for interspecific variation. This can be due to the particular biology of Phytoseiulus species and this shows the difficulty to apply a universal threshold in genetic distances to conclude about the existence of one or several species. Cytb mtDNA sequences were also considered to assess intraspecific variation. The DNA sequences of P. persimilis populations were very similar, probably because they all originated from the West Palearctic region or because of a prevalence of commercialized specimens in natura. For P. macropilis, higher genetic distances were observed and differentiation was noted according to geographic location and, to a smaller extent, pyrethroid resistance. To determine how DNA variation might impact the protein function (CytB fragment considered), the amino acid compositions of the populations studied were compared. No diagnostic mutation was observed between pyrethroid resistant and susceptible populations, whereas four mutations were identified between populations of P. macropilis separated by 1300km (different climatic conditions). The impact of such mutations is discussed but knowledge is scarce, which makes it difficult to root testable hypotheses. The protein analysis clearly opens new perspectives in Phytoseiidae studies.

Effects of botanical acaricides on Raoiella indica and Oligonychus sp. and their toxicity on two species of phytoseiid predatory mites

In this study, three commercial botanical acaricides (BA) were evaluated on two species of phytophagous mites, the red palm mite (Raiella indica) and the papaya mite (Oligonychus sp.). The toxicity of the BA on the predatory mites Neoseiulus californicus and Phytoseiulus persimilis was also assessed. For R. indica, CinnAcar and EPA-90 caused more than 90% decrease in the population density in the laboratory. In field trial, CinnAcar was the most effective in suppressing the mite population density. For Oligonychus sp., CinnAcar and EPA-90 caused up to 88.5 and 95.2% mortality in the laboratory. In greenhouse trial, EPA-90 caused more than 90% decrease in the population density of motile stages. Residual exposure showed that EPA-90 had moderate toxicity to the phytoseiid predators, causing 48% mortality in N. californicus and 55% mortality in P. persimilis, whereas CinnAcar and NeemAcar produced 22 to 32% mortality.

<p class="Body"><strong>Functional response of <em>Amblyseius andersoni </em>and <em>Neoseiulus neoreticuloides</em> (Acari: Phytoseiidae) to adults of the wolfberry gall mite <em>Aceria pallida </em>(Acari: Eriophyoidae)</strong></p>

The gall mite, Aceria pallida Keifer (Acari: Eriophyoidae) is an economically important pest of wolfberry Lycium barbarum L. and can cause significant losses to plant production. Two species of phytoseiid predatory mites, Amblyseius andersoni Chant and Neoseiulus neoreticuloides Liang & Hu were found on L. barbarum in Bayan Nur city, Inner Mongolia, China. We assessed the potential of these two phytoseiid species as biological control agents against A. pallida, using functional response experiments with seven prey densities (5, 10, 20, 40, 60, 80 and 100 adults of A. pallida) on a wolfberry leaf under 25ºC ± 1ºC, 60% ± 5% RH and a 16:8 h (L:D) photoperiod. Overall, the predation of both species increased with increase in prey density. The consumption of A. andersoni female was significantly greater than that of conspecific males and N. neoreticuloides female at high prey densities. Both phytoseiid species displayed a type II functional response to A. pallida. Female A. andersoni had a higher attack rate (5.961) and a shorter handling time (0.014 d) than male A. andersoni (1.619; 0.019 d) and female N. neoreticuloides (0.719; 0.023 d). The maximum attack rate (T/Th) was estimated to be 71.43 and 52.63 for female and male A. andersoni, respectively, while it was 43.48 for female N. neoreticuloides. Both female and male A. andersoni consistently consumed significantly more prey than N. neoreticuloides across all densities of A. pallida adults.

Some new species records of the predatory mite family Phytoseiidae (Acari: Mesostigmata) from The Netherlands

Thirteen species of phytoseiid mites collected from the Netherlands are re-described and illustrated. Among them 9 are new species records for the Dutch fauna and Metaseiulus (Metaseiulus) smithi (Schuster, 1957) is a new record for Europe. Metaseiulus (Metaseiulus) neosmithi nom. nov. Faraji is proposed as a replacement name for Metaseiulus (Metaseiulus) smithi Denmark & Evans, 2011. Also, Kampimodromus coryli Meshkov, 1999 is considered as a junior synonym of Kampimodromus langei (Wainstein & Arutunjan, 1973).

Description of four new species of phytoseiid mites belonging to the genus emTyphlodromus/em (emAnthoseius/em) De Leon from West Bengal.

We report on a survey of phytoseiid mites associated with medicinal plants in West Bengal, India. Thirteen species were collected during the study, four of which are described as new species in the subgenus Typholodromus (Anthoseius) De Leon, 1959. The new species are Typhlodromus (Anthoseius) bulbosis Karmakar et al. sp. nov., Typhlodromus (Anthoseius) bengalensis Karmakar et al. sp. nov., Typhlodromus (Anthoseius) adhatoda Karmakar et al. sp. nov., and Typhlodromus (Anthoseius) sagaricus Karmakar et al. sp. nov.

Unexpected Effects of Local Management and Landscape Composition on Predatory Mites and Their Food Resources in Vineyards.

Simple SummarySustainable agriculture becomes more important for biodiversity conservation and environmental protection. Viticulture is characterized by relatively high pesticide inputs, which could decrease arthropod populations and biological pest control in vineyards. This problem could be counteracted with management practices such as the implementation of diverse vegetation cover in the vineyard inter-rows, reduced pesticide input in integrated or organic vineyards, and a diverse landscape with trees and hedges. We examined the influence of these factors on predatory mites, which play a crucial role as natural enemies for pest mites on vines, and pollen as important alternative food source for predatory mites in 32 organic and integrated Austrian vineyards. Predatory mites benefited from integrated pesticide management and spontaneous vegetation cover in vineyard inter-rows. Pest mite populations were very low and sometimes completely absent on vines. This showed that agri-environmental schemes should consider less intensive pesticide use and spontaneous vegetation cover in the vineyard inter-row due to the beneficial effect on predatory mite populations and their related biological control potential in vineyards.Viticultural practices and landscape composition are the main drivers influencing biological pest control in vineyards. Predatory mites, mainly phytoseiid (Phytoseiidae) and tydeoid mites (Tydeidae), are important to control phytophagous mites (Tetranychidae and Eriophyidae) on vines. In the absence of arthropod prey, pollen is an important food source for predatory mites. In 32 paired vineyards located in Burgenland/Austria, we examined the effect of landscape composition, management type (organic/integrated), pesticide use, and cover crop diversity of the inter-row on the densities of phytoseiid, tydeoid, and phytophagous mites. In addition, we sampled pollen on vine leaves. Typhlodromus pyri Scheuten was the main phytoseiid mite species and Tydeus goetzi Schruft the main tydeoid species. Interestingly, the area-related acute pesticide toxicity loading was higher in organic than in integrated vineyards. The densities of phytoseiid and tydeoid mites was higher in integrated vineyards and in vineyards with spontaneous vegetation. Their population also profited from an increased viticultural area at the landscape scale. Eriophyoid mite densities were extremely low across all vineyards and spider mites were absent. Biological pest control of phytophagous mites benefits from less intensive pesticide use and spontaneous vegetation cover in vineyard inter-rows, which should be considered in agri-environmental schemes.

Predatory mites (Acari: Mesostigmata: Phytoseiidae) intercepted from samples imported to Taiwan, with description of a new species.

Global trade has increased the invasion risk of exotic organisms and damaged agricultural and natural ecosystems. The Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ) handles quarantine services of animal- and plant-associated pests and diseases in Taiwan. The predatory mite family Phytoseiidae (Acari: Mesostigmata) is a well-known group due to the potential use of certain species as biocontrol agents for small phytophagous pests. Some species are available in commercial markets and frequently used in biological control in many agricultural systems, especially in greenhouse crops. However, exotic biological control agents may interfere with natural or naturalised populations of predatory mites and they may threaten indigenous populations via intraguild predation. The present study aims to provide a checklist of phytoseiid mite species found in plant quarantine from 2006-2013. Twenty-five species belonging to two subfamilies and eight genera were found in samples imported to Taiwan from twelve countries, including one new species Typhlodromus (Anthoseius) ueckermanni sp. nov. from South Africa. The checklist provides distribution, remarks, and also an identification key for all species.

Neoseiulus longispinosus (Evans) – blessing of Phytoseiids

Predatory mites, comprising of members Phytoseiidae, Cheyletidae, Cunaxidae, Stigmaeidae, Bdellidae, Tydeidae, Anystidae and Erythraeidae are those which feed on phytophagous mites and small insects. Among the entire predatory mites group, Phytoseiidae are the most important one because of their potential ability in controlling mite pests and small squashy-bodied insect pests. Phytoseiids are one of the most investigated and squeezed group of all predatory mites. In a farming nation like India, predatory mites merit extraordinary notice where agriculture, being the prime livelihood is consistently under the danger of pestilence. Many species of phytoseiids are mass cultured and released on the field as a bio-control agent, among which Neoseiulus longispinosus (Evans) holds an important position due to its immense potential of predation and so this article reviews available data on the biology, predation and mass rearing of this important Phytoseiid mite species.

Alarming evidence of widespread mite extinctions in the shadows of plant, insect and vertebrate extinctions

AbstractThis paper, which addresses the issue of the extinction of mite species at the global scale for the first time, highlights mite diversity, assesses the evidence for an extinction process, discusses contributing factors and estimates losses. The ~1 250 000 mite species occupy an enormous variety of terrestrial and freshwater ecosystems from the equator to the polar regions and to high altitudes. Some groups provide essential ecosystem services, including the incorporation of organic matter into the soil. The maintenance of mite diversity is inextricably linked to the continuance of floristic diversity, habitat complexity and insect diversity. The majority of mite species are assumed to be in the tropical rainforests, of which >50% has been destroyed or severely degraded. Most biodiversity hotspots are in tropical forests; endemic phytoseiid mite species are at least 17 times more concentrated in the hotspots than outside. Habitat destruction and degradation continue on an enormous scale, with increasing human population growth and resource consumption the overarching drivers of extinction. Moreover, climate change is likely to be worsening the effects of the other drivers at an increasing rate. The small body of direct evidence and a considerable body of indirect evidence strongly suggest the continuing, widespread extinction of mite species. Based on estimates of overall biodiversity loss, ~15% of mite species were likely to have become extinct by 2000, with losses currently expected to increase by between 0.6% and 6.0% by 2060. More detailed information on both spatial differences in mite assemblages and anthropogenic threats worldwide is crucial because they underpin the total number of species and their vulnerability to extinction, respectively. The rapid expansion of the protected area estate to capture the maximum possible area of ecosystem heterogeneity, especially in the biodiversity hotspots, is essential, as is best practice management of these areas.

A new species of Amblyseius Berlese (Acari: Phytoseiidae) from Japan

A new phytoseiid mite species, Amblyseius marunumus sp. n., is described and illustrated based on female and male specimens collected from Gunma, Japan. The new species belongs to the americanus species-group, due to the presence of setae J2 and Z1, and having setae z4 longer than z2. Amblyseius marunumus sp. n. is morphologically close to A. yadongensis Wu, but differs conspicuously in the length of the dorsal idiosomal setae z4, r3, S2, S5 and the shape of spermatheca.

High-quality alternative food reduces cannibalism in the predatory mite Amblyseius herbicolus (Acari: Phytoseiidae)

Predatory mites of the Phytoseiidae family are important biological control agents. Many species of this family are omnivores, i.e., besides on prey, they can feed on plant resources such as nectar and pollen. It has been shown that the addition of alternative food for predators to a crop enhances biological control. However, factors such as food availability and quality can also affect interactions such as cannibalism, and thus influence biological control. We investigated the role of quality of the alternative food in the tendency of Amblyseius herbicolus to engage in cannibalism, a common ecological interaction in many phytoseiid mite species. Cannibalism on eggs by A. herbicolus was significantly reduced in the presence of high-quality food (cattail pollen) compared to egg cannibalism without alternative food, whereas this was not the case in the presence of low-quality food (cotton pollen). This suggests that cattail pollen is a high-quality alternative food, not only because it results in increased development and reproduction of predators, but also because it can minimize cannibalism.

Molecular monitoring of Neoseiulus californicus released from sheltered slow-release sachets for spider mite control in a Japanese pear greenhouse.

A novel system for spider mite control was developed with a slow-release sachet containing Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) protected by a waterproof shelter. Monitoring the efficacy of the predator release system for spider mite control at a Japanese pear greenhouse requires discrimination of N. californicus from other indigenous phytoseiid mite species inhabiting the study site and subsequent identification of the released N. californicus. The report of our earlier study described a PCR-based method for discrimination of N. californicus species. For the present study, we first examined phytoseiid mite species composition in the greenhouse. Subsequently, we developed microsatellite markers to identify the released N. californicus. Finally, we installed the predator release system in the greenhouse and conducted a population survey of phytoseiid and spider mites. Results demonstrated that approximately 1month is necessary for distribution of the released N. californicus on the leaves.

Controlling the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) by releasing the predatory phytoseiid mites and pesticides on pepper in a greenhouse

Two programs for controlling the western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), were evaluated. Greenhouse experiments were conducted for reducing F. occidentalis populations on pepper plants. The first program was by releasing four phytoseiid predacious mite species namely Neoseiulus arundonaxi (Metwally and Sanad), N. barkeri (Hughes), N. bicaudus (Wainstein), and Cydnoseius negevi (Swirski and Amitai) in the presence of blue sticky traps. The second one was by applying four sequential applications of different pesticides. Results showed that two releases of N. bicaudus, N. barkeri, and N. arundonaxi in the presence of the blue sticky traps reduced WFT population by 45 to 56%. The best control management of the WFT was by the following insecticides: chlorfenapyr, imidacloprid, azadirachtin, and agricultural potassium soap (third program).

Amblyseius swirskii Henriot ve Neoseiulus californicus’un (McGregor) (Mesostigmata: Phytoseiidae) Tetranychus urticae’nin Koch (Trombidiformes: Tetranychidae) yumurta ve nimf dönemleri arasındaki tercihi

Tetranychus urticae Koch (Trombidiformes: Tetranychidae), two-spotted spider mite, is a pest mite species that feed on a wide range of plants around the world. Neoseiulus californicus (McGregor) (Mesostigmata: Phytoseiidae) is shown as a predatory mite to be a very efficient biological control agent of T. urticae. Amblyseius swirskii Athias-Henriot (Mesostigmata: Phytoseiidae) is another phytoseiid mite species which can feed and reproduce on a wide range of food sources, including T. urticae. Information about the prey stage preference of a predator is valuable for evaluations of the potential of predatory mites to control of pests. We therefore analyzed the prey-stage preferences of A. swirskii and N. californicus to eggs and nymphs of T. urticae at 15:15, 10:20, and 20:10 egg: nymph ratios under controlled conditions (25±1 °C, 65±5% RH and 16-h light: 8-h dark photoperiod). The experiment was carried out on abaxial surfaces of bean leaf discs with a diameter of 2 cm. Starved (for 24 h), 2-3 days-old gravid females of A. swirskii and N. californicus were used in the experiment. One predatory mite was placed individually on each bean leaf disc infested with 15:15, 10:20 and 20:10 ratios of T. urticae egg: nymph. After 24 h of feeding, the numbers of prey consumed for each prey stage were recorded. From the results, it is clear that while N. californicus showed no preference between egg and nymphs of T. urticae. A. swirskii preferred nymphs to eggs of T. urticae.

To the species composition of Phytoseiid mites (Parasitiformes, Phytoseiidae) of the National Nature Park "Ichnyansky"(Chernigiv Region, Ukraine)

New data on the species composition and distribution of phytoseiid mites (Parasitiformes, Phytoseiidae) in plant associations of the National Nature Park “Ichnyansky” were obtained. Twenty species from 9 genera of the family Phytoseiidae are recorded: Amblyseius andersoni, Amblyseius herbarius, Amblyseius obtusus, Amblyseius rademacheri, Neoseiulus danilevskyi, Neoseiulus reductus, Neoseiulus zwoelferi, Euseius finlandicus, Kampimodromus aberrans, Kampimodromu corylosus, Dubininellus echinus, Dubininellus juvenis, Typhloctonus tiliarum, Amlydromella halinae, Amlydromella pirianykae, Amlydromella rhenana, Amlydromella clavata, Amlydromella verrucosa, Typhlodromus laurae, Galendromus longipilus. The calculation of the occurrence index (P1, %) of the identified species of phytoseiid showed that its maximum value is observed in E. finlandicus. This species is also the most numerous in the total number of collected specimens in the sample. Kampimodromus aberrans, D. juvenis, G. longipilus, K. corylosus, N. danilevskyi, N. zwoelferi and T. tiliarum should be considered as the most rarely encountered species with index of occurrence of 1.3%. The remaining species have intermediate values of this index. The analysis of literature data on the occurrence of phytoseiid species with the highest value of the index of occurrence (E. finlandicus, A. pirianykae and A. andersoni) in the plant associations of adjacent zones (Polesie and Steppe Zone) allowed us to reveal some regularities. In Polesie, E. finlandicus (Kolodochka, 2011) is the most common species. In the Steppe zone, E. finlandicus also has a high index of occurrence and is the third most common species of predatory phytoseiid mites. Such a high occurrence of this species is caused by a wide range of its potential victims. Euseius finlandicus is an euribiont, however more adapted to shrub vegetation. The decrease in the occurrence index of this species from Polesie to the Steppe Zone is explained by changes in the moisture content of biocenoses, as well as due to the gradual replacement of tree-shrub vegetation of grass. Amlydromella pirianykae and Amblyseius andersoni are found mainly on herbs. The detection of these species on trees and shrubs should be considered as incidental finds. The characteristic biocenoses for these species are the wet bayrachnye forests, floodplains of rivers, meadows. When choosing a biocenosis for habitat, humidity plays a key role. The analysis of the phytoseiid mites species complex in the plant associations of the Ichnyansky National Natural Park showed the presence of one dominant species, one subdominant, five types of first order subdominant and 13 minor community members in the community.

The response of three species of phytoseiid mite (Acari: Phytoseiidae) to synthetic pyrethroid pesticides in the laboratory and the field.

The Kanzawa spider mite, Tetranychus kanzawai Kishida, is a major pest in tea fields [Camellia sinensis (L.) O. Kuntze] in Japan. However, recently, there have been some instances where acaricides are no longer applied as a result of the low occurrence of T. kanzawai in tea fields in Japan. In the period of 2015-2017, surveys of predatory mites in the study tea field detected Amblyseius eharai Amitai and Swirski, Phytoseiulus persimilis Athias-Henriot, Euseius sojaensis (Ehara), Amblyseius obtuserellus Wainstein and Begljarov, and Typhlodromus vulgaris Ehara in tea fields, but not Neoseiulus womersleyi (Schicha), indicating that a major change in the composition of the phytoseiid mite population had occurred. In laboratory studies, we confirmed the ability to avoid synthetic pyrethroid insecticides of the major beneficial mites in tea fields, A. eharai and P. persimilis, but not of E. sojaensis, a predatory mite whose population declined heavily after pesticide application. Attempts are made in this study to associate the decrease in T. kanzawai frequency in Japan with changes in pesticide used, method of spraying, and composition of the phytoseiid mite population. By continuing the method of pesticide spraying ('partial surface'), which leaves refugia in the leaf layer with sub-lethal dosages of pesticide, phytoseiid mites are aided to evade pesticides, resulting in maintenance of the composition of the phytoseiid mite populations in terms of diversity and abundance. Maintaining the diversity and abundance of Phytoseiidae may have contributed to the stabilization of the T. kanzawai population at low densities in Japanese tea fields.