<abstract xmlns="http://www.w3.org/1999/xhtml">

The occurrence and distribution of entomopathogenic nematodes (EPNs) in the Syrian coast regions remain relatively uncharted. To address this gap in our knowledge, an extensive survey of these ecosystems was essential. This study aims to isolate and identify EPNs from diverse ecosystems within the coastal regions. The distribution of EPNs in cultivated and natural environments was analyzed according to habitat, altitude, and sampling season factors. Between 2017 and 2020, EPNs were recovered from 27 out of 821 soil samples (3.28%) and collected from 24 out of 375 sampling sites (6.4%). Based on morphological, morphometric, and molecular (ITS) characteristics, four EPN species were identified: <italic>Heterorhabditis indica</italic> (51.85%), representing the first report of its occurrence in the coastal regions, <italic>H. bacteriophora</italic> (33.33%), <italic>H. pakistanense</italic> (7.4%), which is also reported for the first time in Syria, and <italic>Steinernema affine</italic> (7.4%). There were statistical differences in the abundance and recovery frequency of EPNs in each type of habitat. Additionally, there were statistical differences in the altitude and sampling season recovery frequency.
Co-inertia analysis revealed correlation between the distribution and occurrence of EPNs in vegetation habitats, altitude, and sampling seasons, as well as some soil characteristics. <italic>H. indica</italic> and <italic>H. bacteriophora</italic> were associated with citrus orchards, low-altitude ranges, moderate organic matter, and acidic soil. More specifically, <italic>H. indica</italic> isolates were correlated with olive orchards, vegetable fields, autumn season, and clay, sandy, and sandy loam soils. Meanwhile, <italic>H. bacteriophora</italic> isolates were correlated with tobacco fields, grasslands, alkaline pH, spring season, silty loam, and clay loam soils. <italic>H. pakistanense</italic> was linked to pear orchards, vineyards, moderate pH, and low organic matter. <italic>S. affine</italic> occurred in walnut orchards, silty soil, higher altitudes, and winter season.
The virulence levels of three native EPN isolates (<italic>S. affine</italic>, <italic>H. indica</italic> and <italic>H. bacteriophora</italic>) were evaluated against 3rd and 4th instar larvae (outside and inside mines) and pupae of <italic>T. absoluta</italic>, a destructive pest in Syria. All three native EPN species exhibited ability to infect and kill the insect, with observed significant differences in their virulence. This study provides an understanding of EPN occurrence, distribution, and their potential for application in sustainable pest control strategies in Syria.
</abstract>

The occurrence and distribution of entomopathogenic nematodes (EPNs) in the Syrian coast regions remain relatively uncharted. To address this gap in our knowledge, an extensive survey of these ecosystems was essential. This study aims to isolate and identify EPNs from diverse ecosystems within the coastal regions. The distribution of EPNs in cultivated and natural environments was analyzed according to habitat, altitude, and sampling season factors. Between 2017 and 2020, EPNs were recovered from 27 out of 821 soil samples (3.28%) and collected from 24 out of 375 sampling sites (6.4%). Based on morphological, morphometric, and molecular (ITS) characteristics, four EPN species were identified: Heterorhabditis indica (51.85%), representing the first report of its occurrence in the coastal regions, H. bacteriophora (33.33%), H. pakistanense (7.4%), which is also reported for the first time in Syria, and Steinernema affine (7.4%). There were statistical differences in the abundance and recovery frequency of EPNs in each type of habitat. Additionally, there were statistical differences in the altitude and sampling season recovery frequency.
Co-inertia analysis revealed correlation between the distribution and occurrence of EPNs in vegetation habitats, altitude, and sampling seasons, as well as some soil characteristics. H. indica and H. bacteriophora were associated with citrus orchards, low-altitude ranges, moderate organic matter, and acidic soil. More specifically, H. indica isolates were correlated with olive orchards, vegetable fields, autumn season, and clay, sandy, and sandy loam soils. Meanwhile, H. bacteriophora isolates were correlated with tobacco fields, grasslands, alkaline pH, spring season, silty loam, and clay loam soils. H. pakistanense was linked to pear orchards, vineyards, moderate pH, and low organic matter. S. affine occurred in walnut orchards, silty soil, higher altitudes, and winter season.
The virulence levels of three native EPN isolates (S. affine, H. indica and H. bacteriophora) were evaluated against 3rd and 4th instar larvae (outside and inside mines) and pupae of T. absoluta, a destructive pest in Syria. All three native EPN species exhibited ability to infect and kill the insect, with observed significant differences in their virulence. This study provides an understanding of EPN occurrence, distribution, and their potential for application in sustainable pest control strategies in Syria.

Isolation, identification of entomopathogenic nematodes with insights into their distribution in the Syrian coast regions and virulence against <italic>Tuta absoluta</italic>

Department of Plant Protection, Faculty of Agriculture

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Isolation, identification of entomopathogenic nematodes with insights into their distribution in the Syrian coast regions and virulence against 

The occurrence and distribution of entomopathogenic nematodes (EPNs) in the Syrian coast regions remain relatively uncharted. To address this gap in our...

Isolation, identification of entomopathogenic nematodes with insights into their distribution in the Syrian coast regions and virulence against Tuta absoluta

Article Category: Research Paper

Published Online: Nov 30, 2023

Page range: -

Received: May 18, 2023

DOI: https://doi.org/10.2478/jofnem-2023-0056

Keywords
Identification, Distribution, Biological control, Syria

© 2023 Mai Ali et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Isolation, identification of entomopathogenic nematodes with insights into their distribution in the Syrian coast regions and virulence against Tuta absoluta

Article Category: Research Paper

Published Online: Nov 30, 2023

Page range: -

Received: May 18, 2023

DOI: https://doi.org/10.2478/jofnem-2023-0056

KeywordsIdentification, Distribution, Biological control, Syria

© 2023 Mai Ali et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Identification, Distribution, Biological control, Syria