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Tomato crops are attacked by several pests, including mites. While the main predatory mites are not effective enough to control mite pests, recent studies have shown encouraging results with the European endemic phytoseiid Typhlodromus (Anthoseius) recki. The first objective of the study was to assess the ability of this species to disperse along the tomato stem, considering six genotypes of Solanum lycopersicum, S. peruvianum and S. cheesmaniae with contrasted trichome numbers and types of stem trichomes, accuratetly characterised in a previous study. The second objective was to determine how predator morphological traits can explain dispersal along the tomato stem. For this, ambulatory dispersal ability of females (stem crossing rate success, hesitation and escape behavior, mobility periods) was tested in lab conditions on the eight Solanum genotypes, at four period of time after the predator introduction (10, 25, 55 and 100 min), with a video observation of 5 min at each period. The females were then mounted on slides and body length and width (at the fore hind, middle and back parts) measured. No effect of the tomato genotypes was observed on the dispersal ability of the predator. However, specimens that succeeded in crossing the stem, had a higher percentage of mobility time (79.36%) than those that failed (43.60%). Furthermore, body width at midbody (DSW2) and dorsal shield length (DSL) were negatively correlated with dispersal ability. The mean DSL and DSW2 of the females that succeed to cross were 342.3 and 160.9 μm, respectively vs. 345.6 and 164.9 μm, for females that did not succeed. This suggests that the more slender and relatively small the specimens, the more are mobile and able to successfully cross the stem. The number of glandular trichomes type (GT) VI and to a lesser extent GT I and IV, and non-glandular trichomes (NGT) II&III appear to limit dispersal. The GT VI seems to have a repellent effect. On the opposite, the number of NGT V were positively correlated with high mobility and stem crossing rates. Assuming that the main barrier to biological control efficiency is dispersal along tomato stems, these preliminary results should have implications for biological control success. The proportion of mites with 'optimal dimensions' appears to be low and further studies should be undertaken to better assess the proportion of mites with such ideal dimensions in different populations and also to determine whether these morphological traits are associated with different feeding abilities and/or abiotic conditions., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Viticulture is characterized by substantial pesticide applications, impacting natural enemies. New pest control strategies and management of plant diversity into agrosystems acting as reservoirs of natural enemies are assumed to limit pesticide use. Various studies support this hypothesis but gaps exist on the effect of diversification on Phytoseiidae mites, generalist predators reported as prevalent and efficient natural enemies in vineyards. This study focuses on the effect of cover crop management (no cover crop, spontaneous cover crops with or without agroforestry) and grape variety (resistant cv. Artaban and cv. Syrah) on predatory mites and prey communities, in a newly planted experimental vineyard in South-East France. Samplings were carried out three times a year on vine, cover crops, and co-planted trees. Phytoseiidae, Tydeiidae, Eriophyidae mites and thrips were characterized. Nine Phytoseiidae species were identified on vine, the main ones being Kampimodromus aberrans, Typhlodromus exhilaratus, Phytoseius finitimus and Euseius gallicus. Kampimodromus aberrans was prevalent on the cv. Syrah, highlighting a strong effect of variety. The low unexpected effect of system management observed outcome could be due to several factors, such as the experimental plot size or the influence of vine stress on Phytoseiidae communities in vines with cover crops. All phytoseiid species present on vine were identifed at least once on cover crops and co-planted trees, suggesting their potential role as reservoirs. Further studies should be performed investigating the evolution of communities in this newly-planted experimental system, as well as potential differences in trophic network interactions., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Trichomes are well-known efficient plant defense mechanisms to limit arthropod herbivory, especially in Solanaceae. The present study aims to evaluate the impact of trichome types on the development, survival and dispersal of Tetranychus urticae, and the phytoseiid predatory mite Typhlodromus (Anthoseius) recki. Six Solanum lycopersicum cultivars and two wild Solanum species, S. cheesmaniae and S. peruvianum, presenting contrasting densities and types of trichomes, were considered. Cultivars and species were characterized by counting each trichome type on leaves, petioles and stems. Mites stuck on petiole and stem and alive mites on the leaflet used for mite release and in the whole plant were counted three weeks after T. urticae plant infestation. Tetranychus urticae settlement and dispersal were differently affected by trichomes. Trichome types V and VI did not affect settlement and dispersal, whereas trichome types I and IV on the petiole had the highest impacton mites. Trichomes on leaves slightly affected mite establishment, there appears to be a repellent effect of trichome types I and IV. The low densities of both T. urticae and its predator detected for the cv. Lancaster could not be clearly associated to the trichome types here considered. The predator did not seem to be affected by plant characteristics, but rather by T. urticae numbers on the plant. The trichome traits unfavorable to T. urticae, did not affect the predator which showed high efficiency to control this pest on all the plant genotypes considered, but at a favorable predator:prey ratio (1:1). Altogether, these results are encouraging for the use of T. (A.) recki as a biological control agent of T. urticae regardless of the trichome structure of the tomato cultivars, but other conditions should be tested to conclude on practical implementations., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Mutations in amino acid sequences can affect protein function. Such aspects have been poorly studied for arthropods. As recent studies have shown mutations in cytochrome b (Cytb) associated with geographic locations in several Phytoseiidae species, the present study aims at investigating (i) the mutation pattern in additional species for the Cytb fragment, (ii) the mutation pattern for another mitochondrial amino acid sequence, cytochrome c oxidase subunit 1 (COI), and (iii) factors affecting the mutations observed (taxonomy, plant support, climatic variables, wild vs. commercialised species). Mutations in amino acid sequences were assessed in seven Phytoseiidae species, with populations collected in contrasted environments. The DNA sequences were mainly obtained from published studies and some were newly obtained. Mutations were observed within and between the populations considered for both fragments, with higher mutation rates in Cytb than in COI sequences, confirming the robustness of this former fragment. Plant support and taxonomic position were not related to mutation patterns. A lower number of mutations was observed in commercialised populations than in wild ones. As preliminary tendencies, mutations in Cytb and COI sequences seem associated to temperature and moisture. Such a preliminary approach, attempting to relate mutation to functional adaptations, clearly opens new research tracks for better assessment of the drivers of mite adaptation, in a context of climate change., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

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 1300 km (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., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Species of the family Phytoseiidae are predators of pest mites and small insects. Their biodiversity is not equally known according to regions and supporting plants. This paper focuses on Phytoseiidae species on plants of the family Solanaceae. The Solanaceae contain many cultivated plants, for example tomato on which leaf characteristics hinder Phytoseiidae settlement and dispersal. This study presents (i) results of surveys carried out on Solanaceae in the south of France, and (ii) Phytoseiidae biodiversity on Solanaceae worldwide. Eleven species were retrieved on 20 solanaceous plants in the south of France with four main species: Euseius gallicus, Euseius stipulatus, Phytoseiulus persimilis and Typhlodromus (Anthoseius) recki. The global analysis suggests that much more species might be found enhancing sampling efforts, whatever the biogeographic region considered. Five Phytoseiidae genera concentrate the highest number of reports and species [Amblyseius, Neoseiulus, Euseius, Phytoseius and Typhlodromus (Anthoseius)]. These genera are not evolutionarily related; adaptation on Solanaceae seems to be recent, except in the Neotropical region. The latter region represents the highest number of reports, species and Solanaceae plants sampled, probably as the centre of origin of this plant family. Occurrence probabilities in biogeographic regions and plant genera are provided as a baseline for searching for new predators adapted to Solanaceae.

The family Phytoseiidae contains many predatory mite species and some are used in biological control programs worldwide. The identification of phytoseiid mites is based on tiny morphological structures and sometimes species diagnosis is not easy especially for non-taxonomists. DNA-based approaches may offer a fast and accurate diagnosis to overcome these difficulties, nevertheless more DNA sequences are needed to determine intra- and inter-specific variations and to provide accurate decision rules based on genetic distances between the taxa considered. In this study, we provide the molecular characterization of seven phytoseiid species based on the internal transcribed spacer (ITS) region. Several populations of these species collected in Turkey were considered. A phylogenetic tree was also constructed. Finally, we record the presence of Neoseiulus reductus (Wainstein) in Turkey.

The accurate characterization of biological control agents is a key step in control programs. Recently, Amblyseius largoensis from Thailand were introduced in Brazil to evaluate their efficiency for the control of the red palm mite, Raoiella indica. The aim of this study was to confirm their identification and to characterize the population from Thailand, comparing it to populations of the Americas and Indian Ocean islands. In addition, a population of A. largoensis from New Caledonia, Oceania, of which DNA sequences were available, was included in phylogenetic analyses. Morphometric data obtained for the population of A. largoensis from Thailand were compared to those of populations from Reunion Island and the Americas through univariate and multivariate analyses. Two DNA fragments were amplified and sequenced: the nuclear ribosomal region ITSS and the mitochondrial 12S rRNA. Haplotypes (12S rRNA) and genotypes (ITSS) were identified and phylogenetic analyses using both fragments were conducted separately and combined using maximum likelihood and the Bayesian information criterion. The integrative approach reveals morphometric and molecular variabilities among populations of A. largoensis and shows that the population identified as A. largoensis collected in Thailand, as well as that from New Caledonia, are conspecific to the populations of the Americas and Indian Ocean islands. Populations from the Americas and Asia are more related to each other than with that from the Indian Ocean islands. Hypotheses to explain this clustering are proposed. Data on the molecular intraspecific variability of this predatory mite from remote areas will be helpful for the development of molecular diagnosis.

Species of the family Phytoseiidae are known as predatory mites, some of them being used in crops to control mite pests, all around the world. Neoseiulus (=Cydnodromus) californicus is among the most commonly used Phytoseiidae species in biological control programs, especially in vineyards, orchards and vegetable fields. This species is distributed world-wide but has never been reported from Australia. On the other hand, specimens morphologically close to N. californicus have been assigned to a species called Neoseiulus wearnei, only reported from Australia. Investigations based on morphological and molecular comparisons were carried out to investigate whether these two taxa are conspecific. Morphological analyses showed no significant difference between specimens identified as N. wearnei and N. californicus. Similarly, genetic distances between these taxa were null, showing that all these specimens belong to the same species. Although it is not yet possible to conclude that all the specimens identified as N. wearnei are N. californicus, we can conclude that N. californicus is present in Australia. The information about the biology of N. californicus can thus now be applied to the Australian population of this species for biological control purposes.

Tritrophic studies involving several populations of the predatory mite Phytoseiulus longipes showed distinct life history traits depending on the prey offered and/or the plant substrate. In order to better understand the biology of this predator, the response to several combinations of prey species (Tetranychus evansi and Tetranychus urticae), prey stages (eggs and mobile stages) and plant substrates (bean and tomato leaf discs) has been assessed for two populations of P. longipes. Unlike what was found for life history traits, both populations displayed similar behaviour: they went and stayed more on tomato than on bean, they preferred T. urticae over T. evansi and mobile stages over eggs. Combining the previous life history data with the present results suggests that P. longipes may display host-plant mediated specialization on a prey species, T. evansi. Possible underlying mechanisms are discussed, as well as directions for future work.

The spider mites Tetranychus evansi and T. urticae are key pests of tomato crops, for which no sustainable practical control strategy is available yet. A Brazilian (B) and an Argentinean (A) population of a phytoseiid predatory mite species, Phytoseiulus longipes, are able to develop and reproduce on T. evansi on tomato, whereas a Chilean (C) population is not. In order to better characterize the two distinct feeding behaviours of these three populations, life table data were assessed when the predator was offered T. evansi or T. urticae as prey on bean or tomato leaves. No effect of the prey offered nor the plant substrate was demonstrated on development durations of the three populations. However, immature mortality was low for the Argentinean and the Brazilian populations whatever the prey or plant substrate, whereas 89 % of P. longipes from Chile died before reaching adulthood when fed T. evansi on tomato. No difference in effect on female longevity was detected among the three populations. Finally, the demographic parameters of all populations were lower in presence of tomato compared to beans. Possible explanations for these results are discussed.

Several species of the family Phytoseiidae are known to control mite pests in many crops worldwide. However, biological control success greatly depends on the accurate identification of these predatory mites. Species diagnostics is essentially based on the morphological characters of females. Thus, when only immature stages and/or males are collected, their identification is poorly supported. Molecular tools could be of great help to overcome these difficulties, as molecular sequences are assumed to be identical for the life stage considered. However, one of the essential points is to extract a sufficient DNA amount from a single specimen of immature stages (eggs, protonymphs, deutonymphs) and males (less than 300 μm in length) to amplify and sequence DNA. The markers used were two mitochondrial DNA fragments (12S rRNA and Cytb mtDNA) and the species studied were Typhlodromus (Typhlodromus) exhilaratus and T. (T.) phialatus, two cryptic species, reported to control mite pests in crops of southern Europe and commonly found on the same plants. Despite a low quantity of DNA extracted, particularly for the egg, larva and protonymph stages, DNA was amplified and sequences were obtained from all the life stages considered with the two mtDNA fragments. Sequences from all the developmental stages of T. (T.) exhilaratus were identical and well differentiated from those of its sister-species. However, contaminations were observed especially for eggs and DNA amplified with the Cytb mt marker. Utility of the present results are discussed and protocol improvements are proposed.

This study deals with the long-term effect of agroforestry management (trees within vine crops) on communities of phytoseiid mites. Several plots were considered: vineyards co-planted with Sorbus domestica or Pinus pinea, monocultures of vines and monocultures of S. domestica or P. pinea. All vine plots included two vine cultivars, Syrah and Grenache. Phytoseiid mites have been surveyed in these plots during several years within the previous 10 years. In 2010, samplings were again carried out in these same plots, from May to September, twice a month. Significantly higher densities of Phytoseiidae were observed on the cultivar Syrah (0.85 phytoseiids per leaf) than on Grenache (0.26 phytoseiids per leaf). Furthermore, significantly higher phytoseiid mite densities were observed in the monocultural grapevine plot than in the two co-planted ones. The main species found was Typhlodromus (Typhlodromus) exhilaratus in all vine plots considered. However, Kampimodromus aberrans was observed in the grapevine plots co-planted with the two trees, but never in the monocultural vine plot. Surprisingly, this phytoseiid species was not found on the co-planted trees, nor in the neighbouring uncultivated vegetation. Several hypotheses are discussed to explain such an unexpected distribution. Furthermore, contrary to what has been observed previously, agroforestry management did not seem to favour phytoseiid mite development, especially on the Grenache cultivar. Again, some hypotheses are developed to explain such observations and density modifications.

The abundance and diversity of phytoseiid mites in the vegetal ground cover of a citrus orchard were surveyed by monthly samplings from October 2008 to July 2009. Six different vegetal cover management methods were studied: herbicide application without mowing (Gly), mowing without herbicide application (PV), mowing with herbicide application (AV), late mowing without herbicide application (LMV), cover crop (Neonotonia wightii, Fabaceae) without herbicide application (PNeo) and cover crop with herbicide application (ANeo). Eleven species were present in the ground cover, with Phytoseius rex and Proprioseiopsis mexicanus as major species. Species richness and densities (1.5 ± 4.5) in the Gly treatment were very low, except for one sample 4 months after herbicide treatment. The AV and PV treatments showed poor diversity and very low mite densities (1.2 ± 2.6 and 1.4 ± 1.5, respectively). The LMV treatment showed the highest diversity and high density of phytoseiid mites (6.9 ± 8.8). The ANeo and PNeo treatments also showed generally high diversity, but with variations in time and exhibited the highest density of phytoseiid mites (13.5 ± 12.7 and 13.4 ± 9.1, respectively). Neonotonia wightii as the cover crop seems to act as a reservoir of phytoseiid mites, sustaining abundant and diverse populations all year round. Some naturally occurring plant species such as Achyranthes aspera, Amaranthus dubius and Eleutheranthera ruderalis could also constitute favourable host plants for Phytoseiidae. Results are discussed in relation to the potential of collected phytoseiid species as candidates for biological control of phytophagous mites on Guadeloupean citrus orchards.

This study focuses on the diagnostics of two natural enemy species, belonging to the genus Phytoseiulus in the family Phytoseiidae (sub-family Amblyseiinae): P. macropilis and P. persimilis. These two species are of primary importance in biological control all over the world. However, they are morphologically very similar and specific diagnostics is difficult. This study utilizes mitochondrial molecular markers (12S rRNA and Cytb mtDNA) to differentiate these two species. Morphological analyses showed significant differences between P. persimilis and P. macropilis for 17 morphological characters of the 32 considered. However, despite these significant differences, the ranges of all characters overlap. Only the serration of the macroseta on the basitarsus (StIV) allows the differentiation between P. persimilis and P. macropilis. Despite these small morphological differences, molecular results, for both mitochondrial DNA fragments considered (rRNA and Cytb mtDNA), showed a clear delineation between the specimens of P. macropilis and P. persimilis. This study emphasizes (i) that only one morphological character (serration of the seta StIV) clearly separates these two species, and (ii) the usefulness of an automatical molecular and simple diagnostic tool for accurate differentiation of the two species and ensure the morphological diagnostics. Further studies are proposed, including more DNA sequences especially for P. macropilis.

Two species of Phytoseiidae are found in the same agroecosystem: Typhlodromus exhilaratus prevails in vine plots, while T. phialatus prevails in uncultivated surrounding areas. The objective of the present paper was to investigate whether the poor settlement of T. phialatus in vine plots can be explained by intraguild predation of these two species and/or cannibalism. Predatory abilities of the females on larvae and protonymphs were studied under laboratory conditions. A first experiment was conducted with only conspecific or heterospecific phytoseiid prey, in a second experiment Tetranychus urticae eggs were added to the phytoseiid prey. Oviposition, prey consumption, and escape rates of females were recorded. Oviposition and intraguild predation rates were higher for T. exhilaratus than for T. phialatus. Typhlodromus exhilaratus consumed fewer conspecifics than heterospecific phytoseiids, and oviposited when feeding on both diets. Typhlodromus phialatus consumed equal amounts of con- and heterospecifics. Although these two generalist predators belong to the type III defined by McMurtry and Croft (Annual Review of Entomology 42:291-321, 1997), our results suggest that they have different predation behaviour. However, because these results were obtained in experiments where no choice was given between the two phytoseiid species, they are difficult to link to previous studies conducted on the intraguild predation of the Phytoseiidae. The greater voracity and prolificacy of T. exhilaratus could partially explain the poor settlement of T. phialatus in vineyards and the predominance of T. exhilaratus. However, a full understanding of this phenomenon will require the study of other factors, such as susceptibility to pesticides and micro-climatic conditions, as well as the ability to cope with different food sources and host plants.

The tomato red spider mite, Tetranychus evansi, is reported as a severe pest of tomato and other solanaceous crops from Africa, from Atlantic and Mediterranean Islands, and more recently from the south of Europe (Portugal, Spain and France). A population of the predaceous mite Phytoseiulus longipes has been recently found in Brazil in association with T. evansi. The objective of this paper was to assess the development and reproduction abilities of this strain on T. evansi under laboratory conditions at four temperatures: 15, 20, 25 and 30 degrees C. The duration of the immature phase ranged from 3.1 to 15.4 days, at 30 and 15 degrees C, respectively. Global immature lower thermal threshold was 12.0 degrees C. Immature survival was high at all temperatures tested (minimum of 88% at 30 degrees C). The intrinsic rate of increase (r (m)) of P. longipes ranged from 0.091 to 0.416 female/female/day, at 15 and 30 degrees C, respectively. P. longipes would be able to develop at a wide range of temperatures feeding on T. evansi and has the potential to control T. evansi populations.

Two species of Phytoseiidae predominated in and around vineyards in an experimental site in the south of France: Typhlodromus exhilaratus is the dominant species on grapes, whereas T. phialatus occurs in the uncultivated areas surrounding these crops. To help understand their distribution, this study aims to determine their susceptibility to a fungicide (dimethomorph + mancozeb) and an insecticide (chlorpyriphos-ethyl), which have been widely used at the experimental site for at least four years. The hypothesis tested is that the effects of these two pesticides differ between T. exhilaratus and T. phialatus. Two populations of T. exhilaratus, one collected on a vine crop where the two pesticides were applied and the other in an unsprayed orchard of Sorbus domestica, and one population of T. phialatus collected on Viburnum tinus from uncultivated areas adjacent to the vine crop, were tested under laboratory conditions. The fungicide seems to affect the females of T. phialatus more than those of T. exhilaratus from vine. However, at the recommended field concentration the female mortality rates of the three strains were low and female fecundities were not significantly different. Conversely, mortality rates were very high for the three strains at the recommended field concentration of chlorpyrifos-ethyl. The strain of T. exhilaratus from vine seems to be more tolerant and 20% of females survived the recommended field rate. This suggests better survival after insecticide application than females of T. phialatus (100% mortality at a lower concentration than the recommended rate). As extrapolation of laboratory results to the field is often irrelevant, these differences could be just one of several factors affecting the spatial segregation of the two species in the agrosystem considered. Possible explanations other than pesticides for the poor settlement of T. phialatus in vine plots are discussed.

The abundance and diversity of phytoseiid mites were surveyed from April to September 2003 to 2005 in vineyards (Grenache and Syrah cultivars) co-planted with rows of Sorbus domestica or Pinus pinea and in monoculture plots of grapes in the South of France. Densities of phytoseiid mites were different on the two tree species, with P. pinea a more suitable host than S. domestica. Typhlodromus (Typhlodromus) exhilaratus was the dominant species occurring on grapes and on co-planted rows of S. domestica and P. pinea, whereas T. (T.) phialatus was the most abundant species in monoculture plots of both S. domestica and P. pinea. Factors determining the dominance of T. (T.) phialatus over T. (T.) exhilaratus in monoculture trees are discussed. In this study, agroforestry management did not affect phytoseiid diversity in vineyards, but did affect phytoseiid density, especially in 2005. The results obtained in 2003 and 2004 are not easy to discuss in this regard because of the low densities of mites observed during these 2 years (very dry climatic conditions and pesticide applications).

This study reports (1) a faunistic survey of phytoseiid mites observed inside a vine plot and in neighbouring vegetation (other vine plots and uncultivated areas) and (2) dispersal of phytoseiid mites into the plot studied. These data aim to raise some hypotheses concerning natural colonisation of a vineyard by predatory mites. The study was carried out over 3 years (1999, 2000 and 2001) in an experimental plot planted with two cultivars (Grenache and Syrah) and with Sorbus domestica in a framework of agroforestry investigations. Phytoseiid mites were collected in both cultivated and uncultivated areas surrounding the experimental plot, and their dispersal into the plot studied using "aerial" traps. Densities remained quite low compared to previous studies. The main species encountered in the uncultivated areas and in the traps was Typhlodromus phialatus. Despite the low numbers of phytoseiid mites trapped, densities of phytoseiid mites into the vine field increased during 3 years. Typhlodromus phialatus, the species mainly found in the neighbouring uncultivated areas, was rarely found in vineyards. Another morphologically close species was predominant on vines: Typhlodromus exhilaratus. However, Kampimodromus aberrans the main phytoseiid mite species in vineyards of Southern France was not found in the present survey. Hypotheses for this colonisation process are discussed.

The effect of wind and woody margins on the dispersal and population dynamics of phytoseiid mites was studied in a vine plot for a period of two years. Mites were sampled in the plot and in the surrounding vegetation (crops and natural vegetation) in order to determine phytoseiid mite abundance. The surrounding vegetation was considered to be a reservoir of phytoseiids from where the vine plot could be invaded. Directional and non-directional soil and aerial traps were placed in the plot to determine predatory mite exchange between the two areas. Colonization of the plot occurred in two stages: first, mite migration into the plot, followed by their establishment. The two-year study partially clarified the first of these two stages. Kampimodromus aberrans was the main species caught in the aerial traps. Phytoseiid mite dispersal within the vine plot seemed to be affected by both wind (direction, intensity and regularity) and phytoseiid mite density in the woody margin. However, the woody margin had a large effect only over a short distance. Some observations pointed towards an effect of other reservoir areas but it was not possible to characterize these. The population density of the phytoseiid mites in the plot increased from 1996 to 1998, but these increases are much smaller than one would expect on the basis of the number of mites migrating by air in the plot. Moreover, blocks where most mites were trapped were not the blocks where densities of phytoseiid mites on vine leaves were the largest. It therefore seems likely that not all migrants were able to develop. Their settlement pattern was not determined and this could constitute a potential research focus for the future.