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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

Open Access
|Jan 2021

Figures & Tables

Figure 1:

Iranian population of Oscheius myriophilus (Poinar, 1986). (A) Pharyngeal region of hermaphrodite; (B: Anterior body region of infective juvenile; (C) Male tail, genital papillae, spicules, and gubernaculum; (D) Posterior body region of hermaphrodite; (E) Infective juvenile tail; (F) Vulval region.
Iranian population of Oscheius myriophilus (Poinar, 1986). (A) Pharyngeal region of hermaphrodite; (B: Anterior body region of infective juvenile; (C) Male tail, genital papillae, spicules, and gubernaculum; (D) Posterior body region of hermaphrodite; (E) Infective juvenile tail; (F) Vulval region.

Figure 2:

Iranian population of Oscheius myriophilus (Poinar, 1986). (A) Anterior body region of hermaphrodite; (B) Anterior body region of male; (C) Part of pharynx (male), (D) Anterior body region of infective juvenile; (E) Vulval region; (F, G) Male tail and genital papillae; (H) Infective juvenile tail; (I) Female rectum; (J) Spicule and tail tip; (K) Hermaphrodite tail (scale bars = 10 µm).
Iranian population of Oscheius myriophilus (Poinar, 1986). (A) Anterior body region of hermaphrodite; (B) Anterior body region of male; (C) Part of pharynx (male), (D) Anterior body region of infective juvenile; (E) Vulval region; (F, G) Male tail and genital papillae; (H) Infective juvenile tail; (I) Female rectum; (J) Spicule and tail tip; (K) Hermaphrodite tail (scale bars = 10 µm).

Figure 3:

Bayesian 50% majority rule consensus tree inferred using partial SSU rDNA sequence of Iranian population of Oscheius myriophilus (Poinar, 1986) under the GTR + G + I model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The Iranian population is indicated in bold.
Bayesian 50% majority rule consensus tree inferred using partial SSU rDNA sequence of Iranian population of Oscheius myriophilus (Poinar, 1986) under the GTR + G + I model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The Iranian population is indicated in bold.

Figure 4:

Bayesian 50% majority rule consensus tree inferred using the partial LSU rDNA sequences of Iranian population of Oscheius myriophilus (Poinar, 1986) under the GTR + G + I model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The sequences of Iranian population are indicated in bold.
Bayesian 50% majority rule consensus tree inferred using the partial LSU rDNA sequences of Iranian population of Oscheius myriophilus (Poinar, 1986) under the GTR + G + I model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The sequences of Iranian population are indicated in bold.

Figure 5:

Death of Cydalima perspectalis (Walker, 1859) and Hyphantria cunea (Drury, 1773) larvae after exposure to different doses of Oscheius myriophilus (Poinar, 1986) in 24–144 h post treatment in laboratory bioassays. (A) fourth instar larvae of Cydalima perspectalis exposed to Oscheius myriophilus (B) fifth instar larvae of Cydalima perspectalis exposed to nematode (C) fourth instar larvae of H. cunea exposed to nematode (D) fifth instar larvae of Hyphantria cunea exposed to nematode, Log-rank test (Mantel–Cox) on GraphPad Prism software was performed to determine statistical significance for the death curves. *p< 0.05, **p<0.01, ***p<0.001, ****p<0.0001, compared with control.
Death of Cydalima perspectalis (Walker, 1859) and Hyphantria cunea (Drury, 1773) larvae after exposure to different doses of Oscheius myriophilus (Poinar, 1986) in 24–144 h post treatment in laboratory bioassays. (A) fourth instar larvae of Cydalima perspectalis exposed to Oscheius myriophilus (B) fifth instar larvae of Cydalima perspectalis exposed to nematode (C) fourth instar larvae of H. cunea exposed to nematode (D) fifth instar larvae of Hyphantria cunea exposed to nematode, Log-rank test (Mantel–Cox) on GraphPad Prism software was performed to determine statistical significance for the death curves. *p< 0.05, **p<0.01, ***p<0.001, ****p<0.0001, compared with control.

Comparative LC50 and LC90 values of Oscheius myriophilus (Poinar, 1986) for Cydalima perspectalis (Walker, 1859) and Hyphantria cunea (Drury, 1773) at 48 h post-treatment by EPNs

HostOrganism χ 2 (df=6) P-valueIntercept ± SESlope ± SELC50LC90
C. perspectalis (fourth larval instars) O. myriophilus 66.700.000−0.79 ± 0.060.005 ± 0.000152.70 (68.1–267.1)400.30 (280.2–802.7)
C. perspectalis (fifth larval instars) O. myriophilus 72.180.000−0.68 ± 0.060.005 ± 0.0074.53 (20.70–133.71)217.02 (150.92–438.99)
H. cunea (fourth larval instars) O. myriophilus 65.240.000−0.92 ± 0.060.005 ± 0.000197.30 (110.0–339.1)470.90 (332.3–934.9)
H. cunea (fifth larval instars) O. myriophilus 78.000.000−0.52 ± 0.060.005 ± 0.00099.94 (−20.4–211.27)346.47 (227.4–906.9)

Morphometrics of Oscheius myriophilus (Poinar, 1986) recovered from Gilan province, north Iran, and comparison with data of the type population, the population from Australia and the population from Turkey

This studyType population studied by Poinar (1986) Sudhaus and Schulte (1989) Erbaş et al. (2017)
LocalityIranCaliforniaAustraliaTurkey
Host insect Galleria mellonella Oxidis gracilis (Koch) O. gracilis Gryllotalpa gryllotalpa (L.)
CharacterMaleHermaphroditeInfective larvaeMaleHermaphroditeInfective larvaeMaleHermaphroditeInfective larvae
n 20202010106
L1,002.1 ± 61.31,020 ± 129.6672.3 ± 71.41,2701,320564630.2 ± 31.5
(867–1,053)(862–1,247)(583–791)(830–1,470)(1,200–1,500)(504–611)(841–1,175)(792–1,530)(571.3–693.9)
a15.3 ± 2.119.6 ± 2.124.2 ± 1.825 ± 2.2
(13.2–18.7)(17.0–22.7)(21.0–27.9)(18.4–21.9)(19.1–21.3)(20.5–28.5)
b5.1 ± 0.25.8 ± 0.54.9 ± 0.3 4.7 ± 0.2
(4.8–5.5)(5.0–6.9)(4.6–5.7)(5.16–7.36)(6.8–7.7)(4.0–6.1)(4.2–8.5)(4.3–5.2)
c18.1 ± 0.99.4 ± 0.97.1 ± 0.4 9.3 ± 0.9
(16.6–19.2)(8.0–10.9)(6.6–7.9)(14.8–20.4)(2.2–3.5)(14.4–21.8)(8.9–13.0)(8.3–11.6)
c'1.7 ± 0.075.0 ± 0.55.5 ± 0.3
(1.5–1.8)(4.1–5.7)(5.1–6.6)(3–4)
V%= (distance from anterior end to vulva/L)×10049.9 ± 2.0
(45.5–53.1)
Stoma length17.5 ± 0.517.6 ± 0.816.1 ± 1.41720
(17–18)(17–20)(14–20)(16–19)(18–21)(18–21)
Stoma width3.4 ± 0.54.2 ± 0.22.7 ± 0.33.23.2
(3–4)(4–4.5)(2.5–4)<4.5
Pharynx length196 ± 9.7176.3 ± 17.1134.5 ± 7.1187185129134.6 ± 3.2
(180–208)(144–200)(125–145)(161–200)(174–193)(120–136)(128.8–139.8)
Max. body diam.66.8 ± 11.552.3 ± 6.827.8 ± 3.463622325.4 ± 2.7
(47–79)(42–66)(24–33)(38–80)(57–70)(19–26)(52–72)(52–108)(21.0–30.4)
E pore from anterior end165.9 ± 11.1149.3 ± 9.3116.3 ± 4.6198179107108 ± 6.7
(142–177)(135–167)(110–129)(149–229)(165–190)(97–114)(97.8–118.8)
Nerve ring from anterior end126 ± 4.7121.1 ± 9.794.5 ± 6.715013989110.5 ± 4.9
(118–130)(105–135)(83–105)(117–165)(126–146)(83–96)(100–116.8)
Rectum length63.7 ± 4.879
(55–80)(56–96)
Anal body diam.32.3 ± 1.821.7 ± 2.416.9 ± 0.93925153212.3 ± 1
(30–35)(17–26)(15–18)(32–45)(22–28)(14–16)(10.4–13.8)
Tail55.3 ± 3.3108.1 ± 9.893.7 ± 5.0651177882.1 ± 6.2
(52–60)(90–126)(85–100)(56–72)(108–135)(75–80)(72.2–92.2)
Ratio of tail length to rectum1.7 ± 0.11.5
(1.1–1.8)(1.4–2.3)
Spicules length44.5 ± 3.847
(38–49)(32–54)(27–39)
Spicules width7.1 ± 0.310
(7–8)(8–11)
Gubernaculum length20.0 ± 1.028
(18–21)(19–32)
Gubernaculum width0.9 ± 0.090.87
(0.8–1.1)(0.64–1.20)
D%= (E pore from anterior end/Pharynx length) ×10084.6 ± 3.785.1 ± 6.887.1 ± 3.5
(78.8–90.5)(76.3–100.0)(82.5–94.4)
E%= (E pore from anterior end/Tail) ×100300.2 ± 16.8138.7 ± 10.2125.5 ± 5.0
(273–323)(124.3–160.0)(118.0–136.3)
SW%= (Spicules length/Anal body diam.) ×100137.8 ± 8.2
(126.6–150.0)
GS%=(Gubernaculum length/Spicules length)×10045.1 ± 2.5
(41.6–48.8)
DOI: https://doi.org/10.21307/jofnem-2021-035 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X
Language: English
Page range: 1 - 16
Published on: Jan 1, 2021
Published by: Society of Nematologists, Inc.
In partnership with: Paradigm Publishing Services
Publication frequency: 1 times per year

© 2021 Reihaneh Gholami Ghavamabad, Ali Asghar Talebi, Mohammad Mehrabadi, Mohammad Ebrahim Farashiani, Majid Pedram, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.