Autres familles d’acariens prédateurs d’acariens

- Stigmaeidae- Anystidae- Cheyletidae- Bdellidae- Cunaxidae- Erythraeidae- Tydeida

Vineyard colonisation by predaceous mites (Acari: Phytoseiidae) living in surrounding vegetation

The aim of this work was to study the colonization by phytoseiid mites living in neighboring uncultivated areas of a vineyard in the South of France. The experimental vine plot was co-planted with Sorbus domestica in a framework of agroforestery investigations. This study was carried out during 3 years (1999, 2000 and 2001) in a vine plot planted in 1997. Phytoseiid mites have been collected in cultivated and uncultivated areas surrounding the experimental plot. Dispersal of these mites into the plot has been studied using aerial traps. Phytoseiid mites have been observed in the surrounding cultivated and uncultivated areas. However, densities were quite low. Phytoseiid mites dispersed into the experimental plot, but low densi ties of mites have been caught. Nevertheless, these densities seemed to be sufficient to provide efficient biological control against phytophagous mites. Typhlodromus exhilaratus was the main species trapped. This species was also the main phytoseiid mite collected in the experimental vine field and on S. domestica trees. Densities of mites in the vine field have increased during the three years. Phytoseiid mites seemed to have successfully colonized the experimental vine plot, but Kampimodromus aberrans, the species usually collected in vineyards of South of France, was not the main species observed in this case. The reasons of this colonization process is discussed here

Effects of host plants on distribution, abundance, developmental time and life table parameters of Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae)

The biology and ecology of the date palm mite O. afrasiaticus have been studied through regular inspection in Tunisian oases and laboratory observations. Results indicate that the start date of fruit infestation varied between years and by date palm variety. Start dates ranged from the first week to the third week of July. The period spent by the mite on fruits varied from one variety to another; lasting 8 weeks on the Deglet Noor variety, 2 to 5 weeks on Alig, 2 to 4 weeks on Kentichi dates, and 2 to 4 weeks on Bessr fruits. The Deglet Noor variety was the most susceptible to O. afrasiaticus. Mite populations on the pinnae remained low from May through December. During autumn and spring, O. afrasiaticus was found on sorghum leaves in the orchard ground-cover. A life table study in the laboratory at 27°C on six host plants (fruits of date palms varieties Deglet Noor, Alig, Kentichi, Bessr, and Deglet Noor pinnae and sorghum leaves) showed that the life cycle of O. afrasiaticus differed among host plants with average values ranging between 13 on Alig fruits and 10.9 days on sorghum leaves. Relatively high fecundity was found on sorghum leaves (2 eggs/female/day) during 5.2 oviposition days, while low fecundity values occurred on Deglet Noor pinnae and Alig fruits with 0.7 eggs/female/day during 5.4 days. Average longevity of O. afrasiaticus females ranged from 13.4 to 7.5 days on Deglet Noor fruits and sorghum leaves, respectively. Intrinsic rate of increase (r m) was highest on sorghum leaves (0.171) and Deglet Noor fruits (0.166), and lowest on Alig fruits (0.103). Greater knowledge of life history traits and seasonal abundance of this species is needed in order to design appropriate control strategies.A biologia e ecologia do ácaro da tamareira O. afrasiaticus foram estudadas através de inspeções regulares em oásis Tunisianos e observações em laboratório. Os resultados indicam que a data inicial da infestação dos frutos variou entre os anos e pelo tipo de variedade das tamareiras. Datas iniciais variaram entre a primeira e a terceira semana de julho. O período passado pelo ácaro nos frutos variou de acordo com o tipo de tamareira, sendo de 8 semanas na variedade "Deglet Noor", de 2 a 5 semanas na "Alig", 2 a 4 semanas nas tâmaras "Kentichi", e 2 a 4 semanas nos frutos "Bessr". A variedade "Deglet Noor" foi a mais sensível ao O. afrasiaticus. As Populações de ácaros nas pinhas permaneceram baixas de maio a dezembro. Durante o outono e na primavera, O. afrasiaticus foi encontrado em folhas de sorgo no solo dos pomares. Um estudo tabelado com o ciclo de vida em laboratório, a 27°C, em seis plantas hospedeiras (tâmaras das variedades "Deglet Noor", "Alig", "Kentichi", "Bessr", as pinhas de "Deglet Noor" e folhas de sorgo) mostrou que o ciclo de vida de O. afrasiaticus variou entre as diferentes plantas hospedeiras com valores médios de 13 dias nos frutos Alig e 10,9 dias em folhas de sorgo. Uma fecundidade relativamente alta foi observada em folhas de sorgo (2 ovos/fêmea/dia) durante 5,2 dias de ovipostura, enquanto valores mais baixos de fecundidade foram observados nas pinhas "Deglet Noor" e frutos "Alig" com 0,7 ovos/fêmea/dia durante 5,4 dias. A longevidade média das fêmeas de O. afrasiaticus variou entre 13,4 a 7,5 dias nos frutos "Deglet Noor" e folhas de sorgo, respectivamente. A taxa intrínseca de aumento (r m) foi mais alta em folhas de sorgo (0,171) e frutos "Deglet Noor" (0,166), e mais baixos nos frutos "Alig" (0,103). Um maior conhecimento da história de vida e abundância sazonal desta espécie é necessário para que estratégias apropriadas de controle possam ser elaboradas

Biogeographical analysis within the family Phytoseiidae Berlese (Acari: Mesostigmata): an example from the large sub-genus Typhlodromus (Anthoseius) De Leon

Despite their great interest for pest management, the biogeography of the Phytoseiidae is still poorly known. This study focuses on the spatial distribution of one of the largest taxa within the family: the sub-genus Typhlodromus (Anthoseius) currently comprising 322 species. It also provides a description of five discrete morphological characters used to discriminate between species and easily observed. This survey is the first analysis of the combined distribution of both species and associated morphological characters within the family Phytoseiidae. It reveals the great utility of taxonomic data compilation and associated databases for aspects beyong alpha-taxonomy. The highest number of species of Typhlodromus (Anthoseius) was reported from the East Palearctic region and the lowest from the Neotropical province. This was quite surprising as the highest species diversity of Phytoseiidae is reported from this latter region. Several hypotheses are discussed to explain this observation. In provinces showing the highest number of Typhlodromus (Anthoseius) species, we usually also observed the most diverse morphological forms for the five characters considered. High endemism levels were observed in all the provinces considered, even those where only few species were reported (especially the Neotropical province). Possible synonymies are thus discussed, as species could have been described more than once in different biogeographic provinces. Furthermore, some hypotheses are discussed to explain the high species and morphological diversity of the sub-genus Typhlodromus (Anthoseius) in theWest and East Palaearctic regions. Further phylogenetic analyses are required to test these different hypotheses

Effects of agroforestry on Phytoseiidae communities (Acari: Mesostigmata) in vineyards. A synthesis of a 10-year period of observations

Several species of the predatory mite family Phytoseiidae are of major economic importance for biological pest control in crops, including grapevines. Plant diversification in agrosystems is reported to enhance useful biodiversity and provide ecosystem services. Thus, agroforestry, which consists in co-planting trees and crops, is assumed to be a possible way to ensure regulation of pest outbreaks by phytoseiid mites. This paper investigates the effect of trees ([i]Pinus pinea[/i] and [i]Sorbus domestica[/i]) within vineyards on Phytoseiidae communities. Five experimental plots were considered, two where vines were co-planted with [i]P. pinea[/i] and [i]S. domestica[/i], and three monoculture plots: vines, [i]P. pinea[/i] and [i]S. domestica[/i]. Sampling was carried out on vines and trees in 2003, 2004, 2005, 2010 and 2012. A higher Phytoseiidae diversity was observed in agroforestry plots than in monoculture plots. [i]Kampimodromus aberrans[/i] (replacing [i]T. [T.] exhilaratus[/i]) seemed to colonize these plots 15 years after its plantation, especially when vines were co-planted with [i]P. pinea[/i]. Factors affecting these faunistical changes are discussed. Effects on Phytoseiidae densities differed depending on grape cultivartree species associations. Factors affecting these interactions are discussed; plant diversity does not simply lead to a higher density and diversity of natural enemies

Lutte biologique contre les acariens phytophages

Dans un triple souci d'efficacité de la protection phytosanitaire, d'économie et d'une gestion phytosanitaire plus respectueuse de la santé et de l'environnement, l'utilisation massive de produits phytosanitaires a peu à peu été raisonnée et limitée (premières lignes

Biological control of mites in European vineyards and the impact of natural vegetation

In vineyards, generalist phytoseiids are important in keeping phytophagous mites at economically acceptable levels. Among these predators, Typhlodromus pyri and Kampimodromus aberrans have proven to be most effective, because they increase in numbers in response to mite pests and alternative prey/food, they persist under conditions of prey scarcity, and they can tolerate several fungicides and insecticides. Natural colonization of commercial vineyards by phytoseiids may take several years. Therefore, strains showing field resistance to certain insecticides (e.g., organophosphates) and fungicides (e.g., mancozeb) are of practical interest. Here we report results obtained with releasing T. pyri and K. aberrans strains with different pesticide histories, with emphasis on factors affecting their persistence, i.e., alternative food availability (pollen or downy mildew), leaf morphology, and selective pesticides. Natural vegetation surrounding vineyards may impact the densities of phytoseiids in neighbouring crops. For example, phytoseiid densities on plants surrounding vineyards under IPM in Southern France (Languedoc-Roussillon) were correlated with leaf structures, and K. aberrans density appeared positively affected by high trichome densities and presence of domatia. Also pollen density was significantly correlated with trichome density and domatia (hair tufts). Predatory mites disperse mainly by air currents and hence their dispersion depends on wind intensity and direction. Crop colonization potential (speed, intensity, uniformity) was directly associated with phytoseiid densities and the proximity of natural vegetation. A deep, dense, and tall woody area with suitable host plants constitutes the stablest source of phytoseiids. Natural colonization of vineyards by phytoseiid mites has great potential and it may well be promoted by careful management

Phytoseiid mite diversity (Acari: Mesostigmata) and assessment of their spatial distribution in French apple orchards

The present study reports the results of surveys carried out over two years in 173 apple orchards in France. Eleven species of Phytoseiidae were observed, among them three were dominant: Amblyseius andersoni, Kampimodromus aberrans and Typhlodromus (Typhlodromus) pyri. Cydnodromus californicus was also found but only in some orchards and nearly always in association with one of three dominant species. This observation confirms the faunal modification initiated more than ten years ago. Amblyseius andersoni was recorded in high densities in nearly all the regions considered. Typhlodromus (T.) pyri was also widespread, even if particularly frequent and abundant in the Rh¶ne-Alpes region. Kampimodromus aberrans was localised in some regions; it was especially frequent and abundant in the Mediterranean region. An identification key containing the eleven reported species is provided. TaylorÆs law was applied in order to characterize the Phytoseiidae distribution in apple orchards. The distribution is clearly aggregative, whatever the region and the Phytoseiidae species considered. Relationships between the occupation rate and the mean number of Phytoseiidae per leaf was established and an abacus was constructed to facilitate surveys and the counting during practical assessments of Phytoseiidae fauna in apple orchards

Phytoseiid mites (Acari: Mesostigmata) of Tunisian citrus orchards: Catalogue, biogeography and key for identification

This study presents the results of a survey aimed to determine the species composition of phytoseiid mites on citrus trees, inter-row grasses and conifers planted as break winds within and around citrus orchards. This survey was carried out in fourty six citrus orchards in the main citrus growing regions of Tunisia, from September 2009 to August 2011. Twenty six species belonging to ten genera were found, among which eleven are new for the Tunisian fauna. This paper provides a catalogue of all these species, with some information on their biogeography and biology when available. In addition, a key for the identification of all known Tunisian species (38 species belonging to 17 genera) is given