• Title/Summary/Keyword: Entomopathogenic nematodes

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곤충병원성 선충과 공생박테리아의 지방산 함량 분석

  • Park, Seon-Ho;Kim, Hyo-Hyeon;Kim, Ji-Yeon
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.910-913
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    • 2001
  • The fatty acid compositions of entomopathogenic nematodes Steinernema carpocapsae strain produced in vitro and in vivo were examined. Nematodes cultured both in vitro and in vivo revealed similar fatty acids compositions with respect to 16, 18, 20 carbons. However, the contents of lipids were varied by culture methods. Furthermore, it was distinctive that nematodes cultured in vitro contained fatty acids with 19 carbon. In the case of symbiotic bacterium Xenorhabdus nematophilus isolated from Steinernema carpocapsae, the major lipid component was palmitic (c16:0) fatty acids.

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An Edible Alginate Microcapsulation of Entomopathogenic Nematode, Steinernema carpocapsae (알지닌캡슐을 이용한 곤충병원선충(Steinernema carpocapsae)의 섭식유도형 제제화 기술)

  • 김용균;이승화;유용만;한상찬
    • Korean journal of applied entomology
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    • v.42 no.2
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    • pp.145-152
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    • 2003
  • Field application of the entomopathogenic nematode, Steinernema carpncapsae, is limited by its susceptibility to UV irradiation and desiccation especially at leaf spray control. This study was conducted to develop the control technique using alginate biocapsulation of the nematodes against the beet armyworm, Spodoprera exigua and the tobacco cutworm, Sp. litura that are normally infesting hosts above ground level. The alginate capsules including infective juveniles gave significant feeding toxicities to the larvae of the two lepidopteran species. The lethality followed a typical sigmoid dose-mortality pattern with increase of the nematode densities embedded in the capsules. Moisture content in the capsule was critical to the survival of the infective juveniles. More than 80% nematodes could survive above 10% moisture content remained in the capsule. Remaining moisture content within the capsule was dependent on relative humidity, ambient temperature, and capsule size, but not on citric acid reaction time during capsule formation. More than 80% of infective juveniles in the alginate capsules could survive in distilled water at 15$^{\circ}C$ for 60 days. When these nematode capsules containing welsh onion extract as another phagostimulant were applied on the 3rd instar larvae of Sp. exigua infesting peanut plants, they resulted in about 90% control efficacy. These results indicate that the alginate capsulation can be used for leaf-spray agent of the entomopathogenic nematodes as well as for improved storage purpose.

Characteristics of the Oxygen Uptake Rate of Entomopathogenic Nematodes Steinernema spp. (곤충병원성 선충 Steinernema spp.의 산소 요구도 특성)

  • 김도완;박선호
    • Korean journal of applied entomology
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    • v.38 no.2
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    • pp.123-128
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    • 1999
  • Recently, entomopathogenic nematodes have received a considerable attention as biologicalcontrol agents. For in vitro cultivation, storage and transportation of nematodes, oxygen supply isextremely impotant due to its limited solubility and mass transfer problem. The oxygen uptake rates(OURs) of four different Steinernema species were measured in a 5L bioreactor at varying temperatures.The OURs of the Steinernema spp. were below 0.5 x mmolO'||'&'||' . min in the range of 13-17$^{\circ}$C. TheOURs (mmo102/L - min) of S. glaseri Dongrae and S. carpocapsae Pocheon strains were 0.4 x lo-', 0.75x lo-\ulcorner at 21$^{\circ}$C, 1.5 x lo-\ulcorner, 3.2 x 10-2 at 25"C, and 2.8 x lo-', 5.8 x lo-\ulcorner at 29"C, respectively. However,the OURs were not significantly altered by the agitation speed of 50-150 rpm. The specific oxygenuptake rates (qol) of S. glaseri NC, S. glaseri Dongrae, S. glaseri Mungyeong and S. carpocapsaePocheon strains were 0.3 x 0.5 x 0.3 x and 0.2 x mmolO~/cell min at 25"C,respectively. As the nematode size and temperature were increased, the qo, was also increased.the qo, was also increased.

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Biological Control of Spodoptera depravata (Butler) (Lepidoptera: Noctuidae) Using Entomopathogenic Nematodes (곤충병원성 선충을 이용한 잔디밤나방, Spodoptera depravata(Butler)(나비목: 밤나방과)의 생물적 방제)

  • 강영진;이동운;추호렬;이상명;권태웅;신홍균
    • Korean journal of applied entomology
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    • v.43 no.1
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    • pp.61-70
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    • 2004
  • Environmentally sound control of Japanese lawngrass cutworm, Spodoptera depravata with Korean entomopathogenic nematodes (Heterorhabditis sp. Gyeongsan, Steinernema carpocapsae GSNI , S. glaseri Dongrae, S. longicaudum Nonsan, and S. monticolum Jiri) was evaluated in the laboratory and field. In addition, effect of turf height on the pathogenicity of entomopathogenic nematodes and density of ant (Formica japonica) and spine-tailed earwigs (Forficula scudderi) were investigated in the field. The corrected mortality of 3rd instar of S. depravata larvae was 53.3% to 66.7% 5 days later after treatment of entomopathogenic nematodes. $LC_{50}$ value of S. carpocapsae GSN1 and S. monticolum Jiri against 3rd instar of S. depravata was 6.9 and 3.9, respectively. Pathogenicity of S. carpocapsae GSN1 was different depending on larval stages, i.e., mortality of 2nd instar was the highest representing 73.3% but decreased from 3rd instar. Turf height affected pathogenicity of entomopathogenic nematodes. Mortality of 4th instar of S. depravata was 40.0% by S. carpocapsae GSN1 and 33.3% by S. monticolum Jiri, and 83.3% by fenitrothion, respectively, in the turf height of 14mm, but those were lower in 45mm. The corrected mortality of S. depravata larvae was lower at the entomopathgenic nematode plots than fenitrothion plot in the distribution field of Formica japonica. However, reduction rate of F japonica was higher in fenitrothion by 56.7% compared with 0% in S. carpocapsae GSN1 and 6.7% in S. monticolum Jiri. Turf height influenced control of S. depravate in S. carpocapsae GSN1 and fenitrothion. Control value of S. carpocapsae GSN1 was 62.2% in the turf height of 3-4cm, but not effective at all in 6-8cm and 12-14cm. However, there was not significantly different in fenitrothion plots. Forficula Scudderi was also reduced only in fenitrothion plots. Reduction rate was 100% in 3-4cm, 41.7% in 6-8cm, and 16.7% in 12-14cm, respectively.

Temperature Effects on Korean Entomopathogenic Nematodes, Steinernema glaseri and S. longicaudum, and their Symbiotic Bacteria

  • Hang Dao Thi;Choo, Ho-Yul;Lee, Dong-Woon;Lee, Sang-Myeong;Kaya Harry K.;Park, Chung-Gyoo
    • Journal of Microbiology and Biotechnology
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    • v.17 no.3
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    • pp.420-427
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    • 2007
  • We investigated the temperature effects on the virulence, development, reproduction, and otility of two Korean isolates of entomopathogenic nematodes, Steinernema glaseri Dongrae strain and S. longicaudum Nonsan strain. In addition, we studied the growth and virulence of their respective symbiotic bacterium, Xenorhabdus poinarii for S. glaseri and Xenorhabdus sp. for S. longicaudum, in an insect host at different temperatures. Insects infected with the nematode-bacterium complex or the symbiotic bacterium was placed at $13^{\circ}C,\;18^{\circ}C,\;24^{\circ}C,\;30^{\circ}C,\;or\;35^{\circ}C$ in the dark and the various parameters were monitored. Both nematode species caused mortality at all temperatures tested, with higher mortalities occurring at temperatures between $24^{\circ}C\;and\;30^{\circ}C$. However, S. longicaudum was better adapted to cold temperatures and caused higher mortality at $18^{\circ}C$ than S. glaseri. Both nematode species developed to adult at all temperatures, but no progeny production occurred at $13^{\circ}C\;or\;35^{\circ}C$. For S. glaseri, nematode progeny production was best at inocula levels above 20 infective juveniles/host at $24^{\circ}C\;and\;30^{\circ}C$, but for S. longicaudum, progeny production was generally better at $24^{\circ}C$. Steinernema glaseri showed the greatest motility at $30^{\circ}C$, whereas S. longicaudum showed good motility at $24^{\circ}C\;and\;30^{\circ}C$. Both bacterial species grew at all tested temperatures, but Xenorhabdus sp. was more virulent at low temperatures $(13^{\circ}C\;and\;18^{\circ}C)$ than X. poinarii.

Effect of Soil Moisture and Irrigation on Pathogenicity of Entomopathogenic Nematodes (토양수분과 관수량이 곤충병원성선충의 병원성에 미치는 영향)

  • Lee Dong-Woon;Choi Woo-Geun;Lee Sang-Myeong;Kim Hyeong-Hwan;Choo Ho-Yul
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.2
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    • pp.77-85
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    • 2006
  • Entomopathogenic nematodes (EPNs) have been used as biological control agents for control of various agro-forest insect pests, and are especially effective against soil-dwelling insect pests. Effect of soil moisture on pathogenicity of commercial EPNs for white grub control was evaluated in laboratory, pots, and golf courses. Pathogenicity of EPNs in sand column was variable depending on depth, soil moisture, and EPN species or strain. All tested EPNs (Heterorhabditis sp. GSNUH1, Heterorhabditis sp. GSNUH2, Steinernema carpocapsae GSN1, and S. longicaudum Nonsan strain) showed similar pathogenicity against the bait insect, great wax moth (Galleria mellonella) larva at 2 cm deep at a given soil moisture. However, pathogenicity of the Heterorhabditis sp. GSNUH1 strain was decreased with increasing soil moisture. Pathogenicity of S. carpocapsae GSN1 strain was the lowest in 3% soil moisture (v/w) at 7 cm depth. However, there was no difference in pathogenicity between Heterorhabditis sp. GSNUH2 and S. longicaudum Nonsan strain. Although pathogenicity of Heterorhabditis sp. KCTC 0991BP strain showed no difference against the 2nd instar of Exomala orientalis, that of the S. carpocapsae GSN1 strain was decreased in the laboratory depending on soil moisture. Highly pathogenic strain EPN, Heterorhabditis sp. KCTC 0991BP strain, showed higher pathogenicity at 100 mm irrigation than non-irrigation or 10 mm irrigation. However, poor pathogenic strain EPN, S. carpocapsae GSN1 strain, was not different in pathogenicity from the 2nd instar of Exomala orientalis in creeping bentgrass (Agrostis palustris) depending on irrigation amount in the pot. Pathogenicity of EPNs in field experiment at the tee of Ulsan golf club showed a similar trend to that in the pot experiment.

Biological Control of Lycariella magi(Diptera: Sciaridae), a Pest of Oyster Mushroom, Pleurotus ostreatus Using Entomopathogenic Nematodes (곤충병원성 선충을 이용한 느타리버섯해충, 긴수염버섯파리 (Lycoriella mali)의 생물적방제)

  • 김형환;추호렬;이흥수;박정규;이동운;진병래;추영무
    • Korean journal of applied entomology
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    • v.40 no.1
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    • pp.59-67
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    • 2001
  • The potential of two entomopathogenic nematodes, Sreinernema carpocapsae Pocheon strain and Heterorhabditis bacteriophora Hamyang strain as biological control agents was evaluated against mushroom ny, Lycoriella mali in laboratory and field. Mortality of L. mali was significantly different according to nematode species, concentration, temperature, and developmental stage of fly S. carpocapsae was more effective than H. bacteriophora. Mortality of L. mali was higher at $25^{\circ}C$ than at $20^{\circ}C$. In addition, the 3rd instal and the 4th instar of L. mali were more susceptible than the 2nd instar. The lowest $LC^{50}$ value was represented by S. carpocapsae, 20.0 infective juveniles (Ijs) in the 3rd instar, 27.5 Ijs in the 4th instar at $25^{\circ}C$. S. carpocapsae infected all the developmental stages of L. mali except egg stage and the 1st instar of larva. The highest mortality was shown in adult female representing 74.0% at$20^{\circ}C$ and 80.0% at $25^{\circ}C$.L. mali female adult was influenced by S. carpocapsae in oviposition. The number of eggs by L. mali female infected by nematodes was much lower than uninfected females. S. carpocapsae was dispersed by infected L. mali adult with higher numbers by females than males. When S. carpocapsae was applied at the rate of $2.25{\times}10^{5}\;and\;4.5{\times}10^{5}\;Ijs/1.5\;\textrm{m}^2$ in the mushroom house, mortalities were 42.2% and 81.6%, respectively. The infective juveniles of nematodes survived for 14 days in the mushroom medium. However, nematodes did not affect mushroom growth.

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Hemolytic Activity of Culture Supernatant of Xenorhabdus nematophilus, a Symbiotic Bacterium of Entomopathogenic Nematodes

  • Ryu, Keun-Garp;Bae, Jun-Sung;Kwack, Kyu-Bum;Kwon, O-Yul;Park, Sun-Ho
    • Journal of Microbiology and Biotechnology
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    • v.12 no.3
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    • pp.526-529
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    • 2002
  • Lysis of erythrocytes isolated from human, rabbit, and mouse blood samples was investigated with the culture supernatant of Xenorhabdus nematophilus in a primary form. Prior to use, the culture supernatant of the bacteria was concentrated and the concentrate was dialyzed against Tris-HCl buffer (10 mM, pH 8.1) by ultrafiltration using PM-5 membrane with a molecular weight cut-off of 5,000. At $30^{\circ}C$, the supernatant exhibited no lytic activity towards three types of erythrocytes. However, at $4^{\circ}C$, the supernatant showed selective lytic activity towards rabbit erythrocytes within 90 min. yet did not lyze human or mouse erythrocytes. Microscopic examination clearly revealed that most of the rabbit erythrocytes had been fumed into ghost forms.