Isolation and Characterization of a Parasitic Nematode, Oscheius myriophila (Nematoda: Rhabditida), Associated with European Mole Cricket, Gryllotalpa gryllotalpa (Orthoptera: Gryllotalpidae)

Abstract

B u çalışmada, Türkiye'de Karadeniz Bölgesi'nden toplanan Avrupa danaburnu (Gryllotalpa gryllotalpa L., Orthoptera: Gryllotalpidae) populasyonundan bir nematod suşu izole edildi. Suş, morfometrik ve moleküler (ITS kısmi sekansı) özelliklerine göre Oscheius myriophila olarak tanımlandı. Dauer jüvenillerin bu türleri Rhabditis myriophila (Poinar, 1986)'ya benzemekle birlikte, O. myriophila sahip olduğu; vücut uzunluğu (571.3-693.9) ve baştan sinir halkasına olan uzunluk (100-116.8), ve küçük kuyruk uzunluğu (53.4-76.8) ve anüs genişliği (10.4-13.8) özellikleriyle farklıdır. Bu evre, nematodu bir kılıf gibi kuşatan ikinci evre kütikül içinde bulunan üçüncü evre jüvenildir. rDNA'nın ITS bölgesinin sıraları bu tanımlamayı doğruladı. Bu tür G. gryllotalpa'da ilk kez kaydedildi.

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

“…The body length of dauer larvae of Iranian population were slightly longer (583–791 vs 504–611 μm), and they had posteriorly located excretory pore (110–129 vs 97–114 μm from anterior end) and longer tail (85–100 vs 75–80 μm). Compared to the Turkish population reported by Erbaş et al (2017) , the aforementioned indices were closer (see Table 1 ).…”

“…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 ).…”

“…With decreasing the nematode concentration to 300 IJs/ml, a 81% mortality in fifth instar larvae of FWW (Log-rank test, χ 2 = 21.87, df = 1, P < 0.0001) and 76% mortality in fourth instar larvae of FWW (Logrank test, χ 2 = 16.55, df = 1, P < 0.0001) was observed after 48 h of treatment. Low levels of mortality (32-83%) were recorded whit 50 IJs/ml dosage of O. myriophilus on fifth larval instars of FWW (Logrank test, χ 2 = 7.93, df = 1, P = 0.004) and a 22-65% mortality was observed when 50 IJs/ml dosage of O. myriophilus were applied to fourth instar larvae of FWW (Log-rank test, χ 2 = 4.33, df = 1, P = 0.03) for Figure 4: Bayesian 50% majority rule consensus tree inferred using the partial LSU rDNA sequences of Iranian population of Oscheius myriophilus (Poinar, 1986) (Poinar, 1986) for Cydalima perspectalis (Walker, 1859) and Hyphantria cunea (Drury, 1773) (−20.4-211.27) 346.47 (227.4-906.9) 24-144 h. No significant differences were observed in FWW larval death rate compared with the controls in 10 IJs/ml dosage of nematode on both larval stages.…”

“…The damage caused by the larvae of this pest in the foliage, often leads to a complete defoliation of the trees (Wan et al, 2014). The fall webworm (FWW), Hyphantria cunea (Drury, 1773) (Lepidoptera: Erebidae) is another invasive pest in Hyrcanian forests of Iran. The origin of this moth is North America that has become an invasive pest in Europe and Asia.…”

“…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.…”