Phytoseiidae, A.Berlese, 1916

Tixier, M. - S., Lopes, I., Blanc, G., Dedieu, J. - L. & Kreiter, S., 2014, Phytoseiid Mite Diversity (Acari: Mesostigmata) And Assessment Of Their Spatial Distribution In French Apple Orchards, Acarologia 54 (1), pp. 97-111 : 101-105

Species of Phytoseiidae in French apple orchards

One thousand, nine hundred and eighty-five specimens have been identified. Eleven species of Phytoseiidae have been observed. The list of species, localities and regions is provided in Table 1. Three species were particularly abundant and frequently observed: A. andersoni , K. aberrans and T. (T.) pyri ( Table 2). Cydnodromus californicus was observed in several regions in medium densities, whereas the other seven species were observed in some plots but usually in low densities and in association with the three dominant species ( Tables 2, 3). Apart from the three dominant species, only two ( Euseius gallicus Kreiter and Tixier and Euseius stipulatus [Athias- Henriot]) have been found alone (not occurring with other Phytoseiidae species) in one and three plots, respectively ( Tables 1 and 2). In most of orchards, the three dominant species were not found in association with each other ( Table 3). The highest co-occurrence was found between T. (T.) pyri and A. andersoni co-found in 11 plots among the 173 sampled ( Table 3). Cydnodromus californicus was always found with one of the three dominant species and highest co-occurrence was observed with A. andersoni (in 17 plots among the 20 in which C. californicus was found). Duso et al. (2009) reported the dominance of four species of Phytoseiidae in European orchards: A. andersoni , K. aberrans , T. (T.) pyri as in the present survey. However, they also reported the dominance of another species, Euseius finlandicus (Oudemans) , rather rare in the apple orchards considered in our study.

Table 4 shows the cultivars on which the three dominant species have been found. No clear relationship between apple cultivar and Phytoseiidae species appears as the three dominant species have been found on the most common cultivars.

The list of the eleven species found is provided below with some information on their occurrence and biology.

Amblyseius andersoni was the most frequent and abundant species. It was observed in more than half of the orchards sampled, on 27 apple cultivars (among 34 sampled) and in nearly all the French regions sampled ( Figure 1a, b ). Amblyseius andersoni was dominant in seven of the regions sampled. We can thus question the occurrence of this species in such regions if the number of plots would have been higher. This species is quite common in agrosystems, especially in vineyards and apple orchards in Europe (i.e. Spain, Turkey, Switzerland, Slovenia and Italy) ( Moraes et al. 1986). It is reported to feed and develop on tetranychid mites and to ensure efficient biological control of these mites ( Duso and Camporese 1991; Genini et al. 1991; Koveos and Broufas 2000; Fischer and Mourrut- Salesse 2005; Houten et al. 2005; Lorenzon et al. 2012). Some studies have also shown its ability to develop resistance to pesticides (i.e. Duso et al. 1992; Pozzebon et al. 2002; James 2002, 2003).

Euseius finlandicus has been observed in only one orchard in North West France ( Table 1). One specimen has been observed in this study, but this species is quite common in France, especially on uncultivated shrubs and trees but rarely in crops ( Moraes et al. 1986, 2004). It is reported as a frequent species of apple orchards in Europe by Duso et al. (2009).

Euseius gallicus has been observed in four orchards located in the South-East of France ( Table 1) on three apple cultivars. This species recently described has been reported from shrubs and trees. Nothing is known on its biology and it is morphologically close to E. stipulatus ( Okassa et al. 2009; Tixier et al. 2010).

Euseius stipulatus has been found in four orchards located in the South-East France ( Table 1). This species is commonly found in the southern Europe. It is a very common species in crops, especially in citrus orchards ( Ferragut and Escudero 1997; Sahraoui et al. 2012). Several studies have shown its ability to feed on pollen but also on pests such as Tetranychus urticae (Koch) and Panonychus citri (McGregor) (i.e. Ferragut et al. 1992; Abad- Moyano et al. 2009; Pina et al. 2012). It is usually found on plants with smooth leaves. In the present study, it has been reported on four apple cultivars, but essentially on Golden Delicious, whereas in other orchards with the same cultivar, other Phytoseiidae species have co-occurred.

Kampimodromus aberrans was the second most abundant and frequent species; it was found in 43 orchards and 16 apple cultivars. It was however less widespread than A. andersoni ( Figure 1a, b ). Indeed, it was only present in four regions and it prevailed in Languedoc-Roussillon only. In Franche- ComtØ, K. aberrans was the unique species sampled; however only one plot was considered. This species has a Palearctic distribution; it has been observed both in natural vegetation and crops, especially apple orchards and vineyards (i.e. Tixier et al. 1998, 2000; Kreiter et al. 2002; Duso et al. 2009). However, it is more often reported in untreated apple orchards than in commercial plots ( Duso et al. 2009). In France, this species is the prevalent species in vineyards of southern France, whereas in the North T. (T.) pyri prevails ( Kreiter et al. 2000). This southern distribution is similar to what has been presently observed in French apple orchards. Climatic conditions, especially dry conditions of Mediterranean climate might favour the presence of K. aberrans . However, this species has been reported from higher latitudes, as Germany, Ukraine and Slovakia in orchards ( Schruft 1967, Jedlickova 1991, Kolodochka and Omeri 2007) and presently in North- East France, suggesting that other factors could explain its distribution. Duso et al. (2009) suggested that the occurrence of K. aberrans in Italian apple orchards was linked to pesticide applications and tolerance to pesticides applied. Duso et al. (2009) also showed the importance of apple cultivar leaf characteristics on the occurrence of this latter species. In the present study, we can note that K. aberrans was particularly abundant on cultivars "Reinette", known to have hairy leaves and on the cultivar Chanteclerc. However this latter cultivar has only been sampled in Languedoc-Roussillon, thus it is impossible to determine if the dominance of K. aberrans is due to cultivar or climatic conditions.

Cydnodromus californicus was observed in twenty orchards and eleven cultivars but always at low densities ( Table 4). It was mainly observed in Provence-Alpes-Côte d’Azur and Midi-PyrØnØes ( Table 1). It was the prevailing species in apple orchards in surveys carried out more than ten years ago (Bourgouin et al. 2002). This species tends thus to disappear in apple crops. This evolution is similar to what has been observed in vineyards ( Kreiter et al. 2000). Cydnodromus californicus has been often reported as a species usually present in highly treated plots because of its ability to develop resistance to pesticides (i.e. Fauvel and Bourgoin 1993; Castagnoli et al. 2005; Cloyd et al. 2006). The fact that this species has disappeared from French orchards and vineyards could be explained by the development of Integrated Pest Management practices and the decreasing of toxic pesticide applications. Duso et al. (2009) observed that K. aberrans increased its densities in apple orchards when pesticides less toxic to Phytoseiids are used; it would be more competitive than other species. However, additional studies should be carried out to confirm this hypothesis.

Paraseiulus triporus (Chant and Yoshida-Shaul) was found on five cultivars in five orchards located in South of France ( Table 1). The densities were always low. This species is rather common in the entire West Palearctic region; it has been reported from apples in Sweden, Italy and The Netherlands ( Moraes et al. 2004). Nothing is known on its biology.

Typhlodromus (Anthoseius) rhenanoides Athias- Henriot was found in one apple (cultivar Golden Delicious) orchard in South of France, only ( Table 2). It has been observed on apples in Spain and Portugal and on vines in France ( Kreiter et al. 2000). However, this species is rarely reported from crops.

Typhlodromus (Typhlodromus) baccettii Lombardini was found in one apple orchard (cultivar Red Winter) in South of France. It has been reported from apples only from Norway ( Edland and Evans 1998). Nothing is known on its biology. It is a quite rare species only reported from Europe. It is the second record of this species in France ( Tixier et al. 2006).

Typhlodromus (Typhlodromus) pyri was found in nearly all the regions, 40 orchards and 21 apple cultivars ( Figure 1a, b ). However, even if present in many regions, it was observed only in some plots. It is interesting to note the dominance of this species in the regions Rhône-Alpes and Basse-Normandie. This species is quite common in apple orchards and vineyards all over the world ( Hardman et al. 1991; Moraes et al. 1986, 2004; Roda et al. 2003). Several studies have shown its ability to control mite pests and to resist somewhat to pesticide applications (i.e. Genini et al. 1991; Bonafos et al. 2007). Roda et al. (2003) showed that apple leaf pubescence could affect the densities of T. (T.) pyri because of pollen and fungi spore retention. In the present study, no clear effect of apple cultivar on its occurrence has been observed ( Table 4).

Phytoseius horridus Ribaga was found in one apple orchard (11 specimens identified on the cultivar Karmerrien) in North West of France ( Table 1). It is the first report of this species in France. It has also been observed on apples in Spain (Miaearro et al. 2002). Nothing is known on the biology of this west Palearctic species.

In order to assist the identification of the females of the Phytoseiidae species reported in apple orchards in France, an identification key is provided below.

Figures

FIGURE 1: French regions sampled (with the number of orchards considered) and: a – proportions of dominant species in each region in regards to mite densities; b – proportions of dominant species in each region in regards to number of plots occupied.