A survey investigating the diversity and distribution of entomopathogenic nematodes in the UK and the first confirmed UK record of Steinernema carpocapsae

Abstract

Summary Entomopathogenic nematodes (EPN) of the families Steinernematidae and Heterorhabditidae are lethal insect parasites that have been commercialised as biological control agents. EPN have been isolated from across the world but it has been more than 20 years since the last survey of the UK, and species like Steinernema carpocapsae have never been found here and positively identified through molecular biology. We collected 518 soil samples from a diverse range of habitats across the UK and baited them with Galleria mellonella to isolate EPN. Dead G. mellonella were placed in White traps and emergent EPN underwent DNA barcoding analyses. From the 518 samples, 3.5% were positive for EPN. No Heterorhabditis species were found, but seven isolates of S. glaseri, one isolate of S. feltiae, eight isolates of S. affine and two isolates of S. carpocapsae were found. This was the first confirmed record of S. carpocapsae in the UK.

Evaluation of indigenous entomopathogenic nematodes in Southwest China as potential biocontrol agents against Spodoptera litura (Lepidoptera: Noctuidae)

“…To address the knowledge gap, we conducted a survey of the biodiversity and distribution of EPN fauna in Yunnan province by collecting 789 soil samples from 232 sites during 2017 and 2018. The major objectives of the present study were (i) to investigate the natural occurrence of indigenous EPNs in the entire Yunnan province by standard genotyping procedures ( Al-Zaidawi et al, 2019 ; Edmunds et al, 2018 ), and (ii) to test the virulence of the detected indigenous EPNs isolates against S. litura.…”

Pathogenicity and environmental tolerance of commercial and UK native entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) to the larvae of mosquitoes (Aedes aegypti and Ochlerotatus detritus)

“…Thurston et al (1994) even found that H. bacteriophora virulence was enhanced by low levels of salinity but higher concentrations affected survival. Our most salinity-tolerant strain was S. glaseri 367, which was the only EPN isolate from an extensive survey of Lundy Island (Edmunds et al 2018).…”

“…Service (1977) reported finding larvae of Ochlerotatus cantans infected with several nematodes, but these were unidentified mermithids and not EPNs. To investigate this further we used G. mellonella baiting of several samples from the Little Neston area collected in a previous study (Edmunds et al 2018) but found no EPNs, likely due to unsuitability of the heavy clay substrate of this habitat for EPNs (Kung et al 1990). Therefore, it seems O. detritus may not come into contact with EPNs frequently, and perhaps therefore has not evolved defences against them, making them particularly susceptible to attack.…”