Oscheius myriophila (Nematoda: Rhabditida) isolated in sugar cane soils in Mexico with potential to be used as entomopathogenic nematode

Abstract

A survey of entomopathogenic nematodes was conducted in sugar cane crops in a total of 14 soils, and positive results were obtained for strain MC5-2014 in the municipality of Tepalcingo, Morelos, in soil with a sandy loam texture and a pH of 6.4. Species determination was performed via morphological and morphometric techniques by searching for a tubular stoma with a swollen cylindrical pharyngeal body and a metacorpus in the basal part. The range of body length ( L ) was 750 to 1200 μm in females and 720 to 910 μm in males, while the corresponding maximum widths ( W ) of the body were 30 to 60 μm and 20 to 30 μm, respectively. Males exhibited bursa with a 1 + 1 + 3 + 3 distribution of papillae, and females exhibited a vulva located at the mid-body. For molecular identification, the ITS region of ribosomal DNA was used. Virulence tests (LC 50 ) were conducted with Galleria mellonella , and a value of 4.732 was obtained for infective juveniles (IJs). Taking taxonomic and molecular characteristics into account, the isolate was determined to be Oscheius myriophila . The isolation of this strain represents the first geographic report of O. myriophila in Mexico, and it should be noted that the cultivation of sugar cane occurs with constant application of insecticides, herbicides, fungicides, and fertilizers as well as harvesting activities such as burning of the crop for harvest. The O. myriophila isolate has the potential to be used in the future as a method of biological control in our country.

First record of Oscheius myriophilus (Poinar, 1986) (Rhabditida: Rhabditidae) from Iran; and its efficacy against two economic forest trees pests, Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) and Hyphantria cunea (Drury, 1773) (Lepidoptera: Erebidae) in laboratory condition

“…Oscheius myriophilus belongs to the insectivorous group because of its lips, posterior body region and spicules features. It was originally isolated from the gut lumen, malpighian tubes and haemocoel of the garden millipede, Oxidis gracilis , in California ( Poinar, 1986 ), and was later recovered in Australia ( Sudhaus and Schulte, 1989 ), Turkey ( Erbaş et al, 2017 ), and Mexico ( Castro-Ortega et al, 2020 ).…”

“…The virulence of Oscheius myriophilus against Galleria mellonella larvae was investigated by Castro-Ortega et al (2020) and the LC50 value of 4.732 was calculated. According to them, Oscheius myriophilus has the potential to be used as a biological control agent.…”

“…on insects, a behavior of which mainly correlated with the endosymbiont bacteria belonging to two genera Serratia Bizio, 1823 and Enterococcus (ex Thiercelin and Jouhaud, 1903( e.g. Oscheius rugaoensis Zhang et al, 2012 ( Zhang et al, 2012 ), O. chongmingensis Zhang et al, 2008 ( Fu and Liu, 2019 ; Liu et al, 2012 ), O. myriophilus ( Liu et al, 2016 ; Castro-Ortega et al, 2020 ), O. microvilli Zhou et al, 2017 ( Zhou et al, 2017 ), O. safricana Serepa-Dlamini and Gray, 2018 ( Serepa-Dlamini and Gray, 2018 ) and O. basothovii Lephoto and Gray, 2019 ( Lephoto et al, 2015 ; Lephoto and Gray, 2019 ). The bacterial symbiont is the important and often overlooked determinant of success of an entomopathogenic nematode ( Labaude and Griffin, 2018 ).…”

“…O. myriophilus was described as an associate of the garden millipede, Oxidis gracilis (Koch) (Diplopoda: Paradoxosomatidae) in California by Poinar (1986) . It was later isolated from millipedes in South Australia by Sudhaus and Schulte (1989) , European mole cricket, Gryllotalpa gryllotalpa L. from the Black Sea region of Turkey ( Erbaş et al, 2017 ) and a sugar cane crop soil, in Mexico ( Castro-Ortega et al, 2020 ). Recent studies by Liu et al (2016) have shown that O. myriophilus is an entomopathogenic nematode; being associated with the bacterium Serratia nematodiphila Zhang et al, 2009 .…”

“…Recent studies by Liu et al (2016) have shown that O. myriophilus is an entomopathogenic nematode; being associated with the bacterium Serratia nematodiphila Zhang et al, 2009 . Castro-Ortega et al (2020) isolated the bacterial colonies Serratia marcescens Bizio, 1823 from Oscheius myriophilus, the bacterium which causes a 100% mortality of the 5th instar larvae of Galleria mellonella L. in 1 × 10 5 concentration. According to them, Oscheius myriophilus has the potential to be used in the future as a biological control agent in Mexico.…”