Abstract
Abstract Characterizing entomopathogenic nematode (EPN) biogeography with a goal of augmentation and conservation biological control requires fine-scale taxonomic resolution, because closely related EPN species can exhibit divergent phenotypes for key properties such as habitat adaptation and insect host specificity. Consequently, we employed high throughput genome sequencing (HTS) to identify and compare EPNs and natural enemies of EPNs in 58 citrus orchards in 2 ecoregions in Egypt (El Beheira and Al Qalyubia governorates). We designed improved primers targeting the ITS2 rDNA to discriminate EPN species and used pre-reported primers targeting D2-D3 region for soil microarthropods. Five EPN species (Heterorhabditis bacteriophora, H. indica, H. taysearae, Steinernema glaseri, and S. scapterisci) and one steinernematid not represented in Genbank databases were detected. This is the first report of S. scapterisci and possibly the unknown (perhaps undescribed) species in Egypt. Only heterorhabditid species, dominated by H. indica, were detected in the reclaimed, sandy desert soils of El Beheira governorate. In the fine textured, ancient farming lands of the Nile delta all six species were detected, but at lower frequency and abundance. Microarthropod family richness (P = 0.01) and abundance (P = 0.001) was higher in the reclaimed lands than in the Nile Delta. Soil clay content, pH and elevation explained significant variation in the mite community structure. Population density of H. indica, the only EPN found consistently and at high abundance in El-Beheira, was inversely related to abundance of species in the nematophagous mite family Rhodacaridae.
Highlights
Citriculture has an increasing socio-economic im portance in Egypt, but is subjected to considerable yield loss caused by insect pests such as such as the Mediterranean fruit fly Ceratitis capitata, Wiedemann (Diptera: Tephritidae) and hairy rose beetle Tropinota squalida Tropinota squalida, Scopoli (Coleoptera: Scarabaeidae) (Abd-Elgawad, 2020)
22 amplicon sequence variants (ASVs) were identified as entomopathogenic nematode
The factors regulating entomopathogenic nematode (EPN) species occurrence and abundance remain poorly understood despite an ever-expanding catalogue of EPN biogeography (Campos-Herrera et al, 2013, 2019a; Garcia Del Pino and Palomo, 1996; Mráček et al, 1999; Tarasco et al, 2015; Valadas et al, 2014)
Summary
Citriculture has an increasing socio-economic im portance in Egypt, but is subjected to considerable yield loss caused by insect pests such as such as the Mediterranean fruit fly Ceratitis capitata, Wiedemann (Diptera: Tephritidae) and hairy rose beetle Tropinota squalida Tropinota squalida, Scopoli (Coleoptera: Scarabaeidae) (Abd-Elgawad, 2020). Isolating EPN strains from the main citrus producing governorates in Egypt for practical use in biocontrol programs could provide more effective matching of nematodehost-environment in the crop (Abd-Elgawad, 2017, 2020). Al Qalyubia and El-Beheira governorates are major citriculture regions; from 64 sites in Nematode species/ genus
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.