SURVEY OF PHYTOSEIID MITE SPECIES (ACARI: PHYTOSEIIDAE) IN CITRUS ORCHARDS IN LATTAKIA GOVERNORATE, SYRIA

The present study aimed to identify predatory mite species of the family Phytoseiidae on citrus trees and common wild plants species within or around citrus orchards. Surveys were carried out in fifty orchards in seven different sites in Lattakia governorate (the main citrus growing region of Syria). Fifteen phytoseiid species belonging to ten genera were found, among which fourteen are recorded for the first time from Syria. Euseius stipulatus was the most abundant on citrus trees, followed by Typhlodromus (Typhlodromus) athiasae and Amblyseius andersoni. In this study, one female of the species Typhlodromus (Anthoseius) thesbites is rediscovered and illustrated. Information concerning locations, host plants, number of specimens, and measurements of morphological characteristics of each species collected are provided.


INTRODUCTION
Predatory mites of the family Phytoseiidae have been widely studied for the biological control of phytophagous mites and other small arthropods (McMurtry and Croft, 1997). Although more than 2,000 species are known all around the world (Chant and McMurtry, 2007), this fauna has been poorly investigated in Syria. In fact, only two species were recorded in this country in the last catalog of this family (Moraes et al., 2004): Typhlodromus (Anthoseius) porathi Swirski and Amitai (1967) and Eharius hermonensis Amitai and Swirski (1980). Several studies have been carried out in the last decade. Typhlodromus (Typhlodromus) pyri Scheuten (1857) was observed on apple trees in the south of Syria (Swaida governorate) (Jamal, personal communication), and Typhlodromus (Typhlodromus) athi-asae Porath and Swirski (1965) was the only species recorded in vineyards in the central region of Syria (Homs governorate) (Barbar et al., 2012).
The aim of the present paper was to identify phytoseiid mite species in several citrus orchards in Lattakia governorate (northwest Syria).

MATERIALS AND METHODS
Surveys were conducted on 27 April, 05 May 2011 and 01 July 2012.
Leaves of wild plant species within or surrounding each citrus orchard were also collected. Phytoseiid mites were removed from leaves using the "dipping-checking-washing-filtering" method (Boller, 1984). Mites were mounted on slides in Hoyer's medium and dried in an oven at 45°C for one week.
When the number of specimens per species was relatively high, twenty specimens per species were measured. Average measurements and corresponding ranges are given in micrometers. Setal nomenclature is that of Rowell et al. (1978) and Chant and Yoshida-Shaul (1991) for the dorsal and ventral shields of the idiosoma, respectively. The specimens were deposited in the Arthropod Collection of the Department of Plant Protection, Faculty of Agriculture, Al-Baath University, Homs, Syria.  Remarks -The specimens examined are similar to those given in the original description (Athias-Henriot, 1960a) and to those collected in France (Okassa et al., 2009). Chelicera -Fixed digit 25 long, with two prominent and apical teeth, and four minute teeth clustered midway along digit; movable digit 23 long, unidentate. Remarks -Measurements of the specimens collected are close to those of the original description (Athias-Henriot, 1958a). However, setae j3, J2, z2, z4, Z5 and S2 are about 20 -30 % longer than those of specimens from Cape Verde (Ueckermann, 1992) and Ghana (Moraes et al., 2001). The number of teeth on fixed digit of Syrian specimens is close to this illustrated by Ueckermann (1992). However it is different from specimens examined by Cobanoglu (1989) (2-3 teeth), and by Ferragut and Escudero (1997) (3-4 teeth). (Berlese, 1889) Seius degenerans Berlese, 1889:9. Iphiseius degenerans (Berlese) Berlese, 1921: 95. Specimens collected -25 ♀ on Citrus sp., 2 ♀ on Xanthium strumarium and 1 ♀ on Cirsium arvense in 2012 (Tables 1 and 2).
Remarks -This species was previously reported in vineyards in the central region of Syria (Homs governorate) (Barbar et al., 2012).
Remarks -Measurements of the female collected are close to those ofthe original description of Swirski and Amitai (1997) and the redescription of Swirski et al. (1998). However, the dorsal shield of the Syrian female is characterized by the presence of a waist posterolateral to setae s6.

DISCUSSION
A total of fifteen phytoseiid species belonging to ten genera are reportedin the present study. Seven phytoseiid species are reported on citrus trees in 48 of the 50 sampled citrus orchards: Euseius stipulatus was the dominant species (59 %, Figure 7) and was found in all the sites considered (Table  2). Typhlodromus (T.) athiasae and E. scutalis were relatively abundant (12 % and 10 %, respectively, Figure 7) in orchards close to costal region of Lattakia governorate (Al-ya'robiyah, Al-Sanobar, Al-Shir andKarsana, Table 2). On the opposite, A. andersoni and I. degenerans were more abundant in northeast of this governorate (Al-Jinderiyah and Al-Bahlouliyah, Table 2). The two other species T. (A.) thesbites and P. talbii seemed to be rare in Syrian citrus orchards (only one specimen per species was found).
The number of phytoseiid mite species found on uncultivated plant species within or around citrus orchards was relatively high (14 species, Table 1). Some plant species seemed to be favorable to phytoseiid species. In fact, Rubus fructicosus harbored eight species especially P. finitimus and A. andersoni (Table 1) and this latter was abundant on citrus trees in Al-Jinderiyah (Table 2). The number of phytoseiid species encountered on other plants as C. arvense, M. sylvestris and C. sempervirens was also high (four species at least, Table 1), suggesting that these plants could constitute a reservoir for many phytoseiid species such as T. (T.) athiasae and E. stipulatus that were abundant on citrus trees. In conclusion, some species reported in the present paper were abundant on citrus trees and their surrounding vegetation. This result could be useful in biological control programs of phytophagous mites present in Syrian citrus orchards. Further studies are required to identify these predators in citrus orchards at other sites in Lattakia governorate and other Syrian citrus productive regions.