Exp Appl Acarol (2006) 39:227–242 DOI 10.1007/s10493-006-9010-9 Immigration of phytoseiid mites from surrounding uncultivated areas into a newly planted vineyard Marie-Ste´phane Tixier Æ Serge Kreiter Æ Brigitte Cheval Æ Sabine Guichou Æ Philippe Auger Æ Romain Bonafos Received: 28 September 2004 / Accepted: 8 May 2006 / Published online: 28 June 2006 Ó Springer Science+Business Media B.V. 2006 Abstract 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 experi- mental 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 re- mained 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 morpho- logically 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. Keywords Phytoseiidae Æ Uncultivated areas Æ Vineyards Æ Typhlodromus exhilaratus Æ Typhlodromus phialatus Æ Kampimodromus aberrans M.-S. Tixier (&) Æ S. Kreiter Æ B. Cheval Æ S. Guichou Æ P. Auger Æ R. Bonafos Ecole Nationale Supe´rieure Agronomique/Institut National de la Recherche Agronomique, Unite´ Ecologie Animale et Zoologie Agricole, Laboratoire d’Acarologie, 2 place Pierre Viala, 34060 Montpellier cedex 01, France e-mail: [email protected] 123 228 Exp Appl Acarol (2006) 39:227–242 Introduction Predatory mites belonging to the Phytoseiidae family are well known efficient predators of pest mites in several crops. They have often been reported in unculti- vated areas surrounding vineyards (Boller et al. 1988; Duso 1992; Coiutti 1993; Duso et al. 1993; Ragusa et al. 1995; Duso and Fontana 1996; Tixier et al. 1998, 2000a, b), assuming that such areas are reservoirs for these natural enemies. Their plant composition can affect the diversity and the abundance of phytoseiids, due to close relationships between plant characteristics (i.e., leaf pilosity) and mite development (Tixier et al. 1998, 2000b; Kreiter et al. 2002), especially for Kampimodromus aberrans (Oudemans), the main phytoseiid mite in vineyards of Southern Europe, including France (Camporese and Duso 1996; Perez Otero et al. 1997; Duso and Vettorazzo 1999; Kreiter et al. 2000). However, mite exchange between uncultivated and cultivated areas is poorly documented. Some studies using trappings showed that phytoseiid mites are wind dispersed into orchards and vineyards (Hoy et al. 1984, 1985; Tixier et al. 1998, 2000a). The link between phytoseiid mite occurrence in uncultivated and cultivated areas was also shown using faunistic surveys and population dynamics studies (Tixier et al. 1998, 2000a). At last, in some investiga- tions, gene exchange between mite populations living in these areas was assessed (Dunley and Croft 1994; Tixier et al. 2002). The present study aims at the coloni- sation of a newly planted vineyard carrying out faunistic surveys, population dynamics studies and trapping experiments over three consecutive years. Further- more, the plot studied is inter-planted with trees, Sorbus domestica L., in a framework of agroforestry investigations. Few studies deal with the influence of inter-cropping on mite communities and most of them concern herbaceous plants (Corbett et al. 1991; Toko et al. 1996; Castagnoli et al. 1997; Lozzia and Rigamonti 1998). The second objective of this study is to assess abundance and diversity of phytoseiid mites on these trees over 3 years and their potential utility for biological control of mite pests in vineyards. Material and methods The experimental vineplot The experimental plot was a vineyard located at Restinclie`res, 15 km North of Montpellier, Southern France. This plot (4,494 m2, plantation densities: 2.5 · 1m) was planted in 1997 (after reclaiming land for cultivation) with two cultivars, Syrah and Grenache, and six rows of S. domestica (Fig. 1). The two cultivars are equally representated (50% Grenache and 50% Syrah). Pesticides were applied mainly against powdery and downy mildew and Scaphoideus titanus Ball (vector of the phytoplasma inducing a grapevine disease called ‘‘Flavescence dore´e’’). However, pesticides were scarcely applied (2–4 fungicides and 2–3 insecticides per year) with concentrations recommended by the phytosanitary reglementary handbook (Acta 2003). The pesticides were selected according to their side effects on phytoseiid mites (Typhlodromus pyri Scheuten and Kampimodromus aberrans [Oudemans]), pyrethrinoids were avoided (Sentenac et al. 2002) and no acaricide was used during the 3-year study (Table 1). The experimental plot was surrounded by 123 Exp Appl Acarol (2006) 39:227–242 229 V1north North V2 V1south North uncultivated area (300m 2) p 3 p 2 p 1 1 2 3 V3 p 4 p 5 p 6 West uncultivated p 9 p 8 p 7 area 2 (600m ) 4 5 6 V4 p 10 p 11 p 12 V5 7 8 9 p 15 p 14 p 13 South uncultivated area 10 m (40m2) 10 11 12 Aerial traps Samplings plots Sorbus domestica rows Fig. 1 Experimental plot at Restinclie`res, South of France, V1-5 are the neighbouring vine plots and P1-15 correspond to sampled sub-units of the experimental plot uncultivated areas, bearing essentially Pinus sp. and Quercus sp., and by other cultivated vine fields, also planted in 1997 on reclaimed land. Phytoseiid mite occurrence was studied in the experimental plot and in the various neighbouring areas during 3 years. However, prey densities were not accurately studied. Indeed, as almost all phytoseiid mites are generalist predators (McMurtry and Croft 1997), prey occurrence and distribution does not seem to greatly affect phytoseiid distribution (McMurtry 1992; McMurtry and Croft 1997). Furthermore, observa- tions during the seasons have shown that no tetranychid mite occurred in the experimental plot. 123 230 Exp Appl Acarol (2006) 39:227–242 Table 1 Active ingredients used and pests and diseases treated in 1999, 2000 and 2001 on the experimental plot in Restinclie`res (He´rault, France) Pests and diseases 1999 2000 2001 treated Powdery mildew Sulfur (25/VII) Pyrifenox (02/VI, 30/VI) Difenoconazole (16/V) Quinoxyfen (16/VI) Sulfur (27/VI, 15/VII) Sulfur (25/VII, 08/VIII) Downy mildew Copper (06/VII) Fosetyl aluminium (04/V) Fosetyl aluminium Folpel (06/V) Metalaxyl Folpel Metalaxyl Folpel Dimethoate, (06/VIII) (16/V, 02/VI) Mancozebe (20/VI) Zinebe and Copper Folpel (16/VI) Copper (30/VII) (03/VIII) Copper (30/VI, 25/VI) Azoxystrobine (17/VI) Zinebe and Copper (08/VIII, 23/VIII) Scaphoideus titanus Chlorpyrifos ethyl Chlorpyriphos ethyl (16/VI, 30/VI, 25/VII) (15/VI, 30/VI, 24/VII) Phytoseiid mites in the surrounding environment The uncultivated environment Sampling was carried out during 3 years (from 1999 to 2001) in the uncultivated surrounding areas, two or three times per year (1999: 25/V, 06/VII, 17/VIII; 2000: 02/ V, 05/VI; 2001: 15/V, 10/VII, 21/VIII). All plant species were sampled, taking at least 50 leaves per plant species for each sample date. The leaves (50–500 depending on plants) were sampled on different plants belonging to the same species. Each plant species had different Phytoseiidae densities and plant species were not equally represented in each uncultivated area. Thus, in order to compare the total densities of phytoseiid mites in the several uncultivated areas, an index called ‘‘Woody Richness’’ (WR) was used: WR = S (abundance-dominance of a plant species · the density of phytoseiid mites on this species/leaf), where: 1 = plants are rare, 5% of the canopy; 2 = abundant, 5–25%; 3 = moderately abundant, 25–50%; 4 = very abundant, 50–75%; and 5 = dominant, >75% (Tixier et al. 1998). Also, the occurrence of phytoseiid mites in more remote uncultivated areas was studied. Sampling was carried out in 2000 and 2001 in three directions (North-East, North-West, South), each 100 m, 1 km long (10 samplings). At each collecting site, all plant species were sampled taking at least 50 leaves per species. The neighbouring vine plots Sampling was carried out in the six neighbouring vine plots, equally planted with Syrah and Grenache cultivars. Each plot was sampled three times in 2000 and 2001 (2000: 09/V, 20/VI, 01/VIII; 2001: 22/V, 17/VII, 21/VIII). In 1999, the vine plants were young and no leaf was sampled to avoid damage on the plantations. Each neighbouring vine field was divided in several small plots of 400–600 vinestocks each, and at least 30 leaves were collected in each plot for each sampling date (Fig. 1). Each small plot was planted with a single cultivar. 123 Exp Appl Acarol (2006) 39:227–242 231 Phytoseiid mite populations in the experimental vine plot The experimental plot was divided into 15 small plots of 100 vinestocks each to characterise differences in phytoseiid mite densities according to distance from the uncultivated areas. At least 20 leaves were randomly collected in these plots for each sample date (1999: 18/V, 22/VI, 22/VII, 31/VIII; 2000: 16/V, 27/VI, 25/VII, 22/VIII; 2001: 24/IV, 29/V, 26/VI, 24/VII, 04/IX).