New records of phytoseiid mites (Acari: Phytoseiidae) on solanaceous plants in the Syrian coastal region

Phytoseiid mites have been considered the most promising predators for the control of pest mites and small insects. Their use in solanaceous crops for the biological control of major mite pests represents an important challenge and requires continued research. This study aimed at investigating the phytoseiid species and their associated phytophagous mites on eggplant (Solanum melongena), tomato (Solanum lycopersicum) and black nightshade (Solanum nigrum) in the Syrian coastal region between 2018 and 2020, at 40 sites. A total of 12 species of the three subfamilies (Amblyseiinae Muma, Phytoseiinae Berlese, and Typhlodrominae Scheuten) were collected, with Amblysiinae being the most represented. Among them, Amblyseius andersoni (Chant) is a new record for the Syrian fauna. Phytoseiulus persimilis Athias-Henriot was the most abundant (223 specimens; 47.3%) and frequent (found in 22 out of 40 sites) species collected on all plant species surveyed and the only common phytoseiid species in greenhouses. The second most abundant species was Neoseiulus californicus (McGregor) (83 specimens: 17.6%), while the second most frequent was Phytoseius finitimus Ribaga (8 sites). Species found in this study should be considered in future research on phytoseiid mites as biological control agents of pests of tomato and eggplant cultivated in greenhouses and open fields in this region.


Introduction
Several solanaceous plants are of considerable economic importance worldwide because they are used as food, ornamentals and sources of medicinal compounds.In Syria, solanaceous species such as tomato, eggplant, potato, and pepper are widely cultivated.They are affected by some phytophagous mites, among which the two-spotted spider mite and the tomato red spider mite (respectively, Tetranychus urticae Koch and Tetranychus evansi Baker and Pritchard, Tetranychidae), the broad mite (Polyphagotarsonemus latus (Banks), Tarsonemidae), and the tomato russet mite (Aculops lycopersici (Tryon), Eriophyidae) are some of the main pests of solanaceous crops worldwide (Zhang 2003; Navajas et al. 2013).
Phytoseiids are the best known and most studied group of predatory mites, owing to their known successful use for the biological control of small insect and mite pests on numerous crops (McMurtry et al. 2013; Knapp et al. 2018).However, on solanaceous crops, the presence of unfavorable traits (physical and chemical barriers) for phytoseiid predators, notably in tomato, often makes their efficacy unsatisfactory (Gerson et al. 2003; Vervaet et al. 2021; Paspati et al. 2021).The control of the major mite pests of these crops remains a great challenge and requires continued research.Therefore, prospecting for predatory mites in different agroecosystems, as well as on wild host plants which serve as reservoirs, may lead to the discovery of promising species for biological control programs.
The Syrian coastal region, which includes Latakia and Tartus governorates, produces more than a third of the total national production of tomato and eggplant under both open-field and protected conditions (AASA 2020).Surveys were conducted in this region between 2018 and 2020 to identify the natural enemies of phytophagous mites on solanaceous plants.Five phytoseiid species have been reported in association with T. evansi on cultivated and wild solanaceous plants (Dayoub et al. 2022).In this study, we present additional records of phytoseiid mites found in association with other phytophagous mites on solanaceous plants in the Syrian coastal region.

Material and methods
Surveys of phytoseiids and associated phytophagous mites on some wild and cultivated Solanaceae plants were conducted in Latakia and Tartus governorates between 2018 and 2020, at 40 sites.These sites included 37 that were cultivated with tomato, Solanum lycopersicum L., (4 greenhouses + 5 open fields) and eggplant, Solanum melongena L., (7 greenhouses + 21 open fields), as well as three uncultivated areas with naturally growing black nightshade plants (Solanum nigrum L.).At each site, 30 leaves of each plant species were randomly collected, placed in a plastic bag and transported to the laboratory, where samples were examined under a stereomicroscope (Micros, Ladybird MZ1240, Austria).Mites were collected in 70% ethanol, subsequently mounted in Hoyer's medium and identified using a microscope (OPTIKA B195, Italy) with an attached digital camera (OPTIKA C-B10, 10 megapixel, Italy).The measurements of the single newly recorded species from Syria are given in micrometers, adopting the systems of setal notation for the dorsum and venter of Rowell et al. (1978) and Chant and Yoshida-Shaul (1991), respectively.Relevant taxonomic structures were measured using OPTIKA PROVIEW software (version x64, 4.11.18081.20201205).Voucher specimens were deposited at the Laboratory of Plant Protection Research, Faculty of Agriculture, Tishreen University, Latakia, Syria.
Five species of phytophagous mites from three families were found in association with the phytoseiids: T. urticae (Tetranychidae), Brevipalpus obovatus Donnadieu, Brevipalpus californicus (Banks), Tenuipalpus punicae Pritchard and Baker (Tenuipalpidae), and P. latus (Tarsonemidae) (Table 2).Tetranychus urticae was the most common phytophagous species, sometimes found at very high population levels.It was also the sole pest mite collected from greenhouses crops in association with the predatory mite P. persimilis.

Discussion
This study documents the occurrence of 12 phytoseiid species on solanaceous plants in the Syrian coastal region, among which 5 are recorded for the first time in Tartus governorate: Euseius stipulatus (Athias-Henriot), P. persimilis, N. barkeri, N. californicus and T. (A.) recki.One phytoseiid species, (Typhlodromus (Anthoseius) rickeri Chant), was never reported on Solanaceae before, while A. andersoni is a new record for the Syrian phytoseiid fauna, as its previous citations in Syria referred to misidentifications of A. swirskii, according to Barbar et al. (2022).The latter two species are very similar, but can be distinguished by a few morphological characteristics, as the considerably longer seta Z5 and macrosetae SgeIV and StiIV, and the u-shaped spermathecal calyx in A. andersoni, as opposed to the v-shaped calyx in A. swirskii (Ferragut et al. 2010; Döker et al. 2020).
Phytoseiulus persimilis was the predominant phytoseiid species found both in greenhouses and on outdoor solanaceous plants, while the remaining species were mainly collected from outdoor solanaceous plants.In a previous survey for natural enemies of T. evansi on solanaceous plants in the Syrian coastal region, P. persimilis was also the most frequent and abundant phytoseiid species collected (Dayoub et al. 2022).This species is one of the most common phytoseiids reported on solanaceous plants in different countries, certainly because of commercial biological control introductions (Tixier et al. 2020a).In Syria, an Egyptian strain of P. persimilis, adapted to greenhouse conditions, was introduced in 2005, mass reared and released to control T. urticae in greenhouses strawberry in Latakia since 2006 (Halloum and Shaabo 2006).Many evaluations have shown its efficacy for controlling T. urticae in experimental tomato greenhouses in the Syrian coastal region (Mofleh 2010; Sakr et al. 2018).However, we presume that P. persimilis was already present in this region where natural populations of this predator are currently observed on wild plants and in areas where introductions have not been done (Barbar 2013, 2014; Dayoub et al. 2022).In addition, this species has been recorded since the last century in various countries neighboring Syria, as Lebanon (Dosse and Musa 1967) and Turkey (Sekeroglu and Kazak 1993), in areas on the Mediterranean coastal strip bordering the Syrian coastal region.
* New record for Syrian mite fauna

Table 2
Phytoseiid and associated phytophagous mites from each solanaceous species of each sampling site visited between 2018 and 2020 in Latakia and Tartus governorates in the Syrian coastal region.