• Korean journal of applied entomology
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• v.53 no.2
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• pp.141-147
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• 2014

Pinewood nematode (PWN: Bursaphelenchus xylophilus) is known to kill pine tree species that are indigenous to countries where the pest was inadvertently imported, but some cultures from the extraction of dead pines do not damage trees. Experiments were conducted to examine the effect of pre-inoculation of these low-pathogenic pinewood nematode on resistance of pine trees against the pest species. The pre-inoculated pine saplings showed induced resistance which lasted for a year, and repeated inoculation of these low-pathogenic nematodes enhanced tree resistance. All nematode samples extracted from dying or dead pines that had been killed not more than three months before the extraction were pathogenic, and most of those extracted from pines that had been killed 2-3 years before were low-pathogenic. When inoculated in pine saplings, number of low-pathogenic nematodes settled, as studied two days after inoculation, was not different from that of pathogenic ones. However, as studied after 30 days of inoculation, rate of reproduction in low-pathogenic nematodes was far lower than that of pathogenic nematodes. The rate of reproduction of several nematode isolates growing on fungal mat media of Botrytis cinerea varied, but three of four low-pathogenic isolates showed same level of reproduction rates as pathogenic ones.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.170-170
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• 2004

• Korean journal of applied entomology
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• v.44 no.2
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• pp.145-150
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• 2005

Three Korean isolates of entomopathogenic nematodes, Steinernema carpocapsae KCTC 0981BP (ScK), S. glaseri Dongrae (SgD), and Heterorhabditis sp. KCTC 0991BP (HsK), were evaluated for the control of a turfgrass pest, Popillia quadriguttata. Three days after treatment, all nematodes showed high pathogenicity to adult P. quadriguttata with $97.5\%$ mortality by ScK, $90.8\%$ by HsK, and $80\%$ by SgD at the concentration of 900 infective juveniles per adult. Nematode attachment and infection rate to adult P. quadriguttata were various depending on nematode species and inoculation density. The rate of nematode attachment was $90.8\%$ in HsK, $90.6\%$ in SgD, and $35\%$ in ScK, resfectively at the concentration of 900 infective juveniles per adult. The infection rate that represents the rate of detected nematode from inside insect of body was $97.5\%$ in ScK, $ 80\%$ in both HsK and SgD at the 900 concentration of infected juveniles. The infection rate, however, was decreased to $27.5\%$ in ScK, $72.5\%$ in SgD, but no nematodes was detected in HsK at the concentration of 90 infective juveniles.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.58-64
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• 2015

The black cutworm, Agrotis ipsilon (Hufnagel) is a major insect pest of economic crops including turfgrasses on golf courses. The entomopathogenic nematode, Steinernema carpocapsae GSN1 strain (ScG), a Korean isolate, is an effective biological control agent for soil dwelling and greenhouse insect pests in Korea. In addition, ScG is commercially produced in Korea. We conducted laboratory, greenhouse, and field trials to evaluate efficacy of ScG against black cutworms in turfgrasses. A rate of 63 infective juveniles (Ijs) per larva killed >90% of $3^{rd}$ instars feeding in cups of artificial diet within 3 days. In greenhouse trials against cutworms feeding in pots of turfgrass, efficacy of ScG was higher against $4^{th}$ instars than against $2^{nd}$ instars (90.0 vs 81.2% mortality, respectively, at $2,000Ijs\;pot^{-1}$) in perennial ryegrass, and higher against $3^{rd}$ instars in creeping bentgrass, Agrostis palustris than in zoysiagrass, Zoysia japonica (96.7 vs 52.5% mortality at $100,000Ijs\;m^{-2}$) in pot. The corrected mortality of $4^{th}$ instar was 79.9% at the rate of $100,000Ijs\;m^{-2}$ in the creeping bentgrass in the field. So ScG could be used as biological control agent against black cutworm in turfgrass of golf courses.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.314-320
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• 1995

Pathogenicity of Korean entomopathogenic nematodes against local insect pests was different depending on strains or target-insect pests. Mortalities of diamondback moth, Plutella xylostella larvae were 51.8%, 77.8%, 96.3% or 100% in Hanrim Steinernema sp. and 50.0%, 74.1%, 96.3% or 98.1% in Hamyang Heterorhabditis sp. on filter paper when larvae were exposed to 3, 6, 12, or 24 nematodes per larva. Mortalities of them on kale leaves at the same concentration were 44.4%, 63.0%, 76.1%, or 94.5% in Hanrim Steinernema sp. and 79.7%, 81.6%, 94.4%, or 100% in Hamyang Heterorhabditis sp., respectively. In field test, control value of Hanrim Steinernema sp. was 72.0% and that of Hamyang Heterorhabditis sp. was 84.1% in 14 days when 300,000 nematodes were sprayed to each plot ($13.27\m^2$). Although mortalities of rice stem borer, Chilo suppressalis larvae showed no difference at high concentration, Hamyang Heterorhabditis sp. (47.3~100%) was more effective than Hanrim Steinernema sp. (34.3~83.3%) at low concentration, 50~200 nematodes/ml. When chestnut curculio, Curculio sikkimensis larvae were treated with Sancheong Steinernema sp. and Hamyang Heterorhabditis sp., respectively. When pellucid zygaenid, Pryeria sinica larvae were exposed to nematodes, Pocheon Steinernema sp. was effective ranging from 96.7% to 100% but mortalities of them were 63.3~76.7% in Dongrae Steinernema sp..

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.10a
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• pp.30-30
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• 2000

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.11a
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• pp.169-169
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• 2002

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.321-330
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• 1999

Nematodes were isolated using silkwom trap through the investigation of 100 soil samples from various biotopes in Korea. The 30 nematode strains from soil and dead insects by the pathogenicity aganinst silkworms (Bombyx mori mori) and insect pests of Calliphora vomitoria, Pseufazetia separata, Palomena angulosa, and Melolontha incana. Mortailty of the silkworm larvae and pupae were as high as 100% by nematode infection, those of insect of pests were varied from 20 to 100%. The 30 strains of entemopathogenic nematodes were classified into five groups of Rhabditidae, Diplogatroidae, Heterorhabitidae, Steinernematidae, and Tylenchida by morphological criteria. The genetic relationships among the 30 nematode strains were analyzed by various RAPD bands with twenty primers. The 30 nematode strains were classified into six major subgroups on the basis of the genetic similarity coefficient of 0.853. The grouping by RAPD was agree with those of morphological taxa in discrimination of the higher group, however, was not completely agree in the subgroup. The family Steinernematidae belong to Rhabditida was clarified as closer to the Tylenchida, rather than the other Rhabditida of Heterorhabitidae, Rhabditidae, and Diplogatroidae in genetic distance valule. From the result of the morphological classification and RAPD of the genomic DNA showed that genetic relationship analysis furnish infurmation on phylogenetic classification and relationships of entomopathogenic nematodes. The application of genetic similarity will overcome the limitation of taxonomy and classification of morphologically simple nematode. Several primers were confirmed those utility of identification for individual nematode strains, the methods of molecular genetics secured the simplicity, rapidity and accuracy on the selection of entomopathogenic nematodes.

• Proceedings of the Korean Society of Soil Zoology Conference
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• 1998.10a
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• pp.15-15
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• 1998

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.201-209
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• 2006

Five strains of Korean entomopathogenic nematodes (EPN), steinernematids and heterorhabditids were evaluated and tried in laboratory, pot, and vegetable greenhouses for environmentally friendly control of diamondback moth (DBM), Plutella xyiostella, from 2002 to 2005. LC$_{50}$ values of five EPN strains against DBM were different depending on nematode strain and DBM instar. LC$_{50}$ value of Steinernema carpocapsae GSN1 (GSN1) was the lowest representing 2.6$\sim$3.9 infective juveniles (Ijs, 3rd stage) to 2nd to 4th instars of DBM. Pathogenicity of five effective strains against DBM was different depending on nematode strain, concentration, application times, and vegetable in pot. The most effective nematode was GSN1. Steinernema spp. was more effective than Heterorhabditis spp. against DBM. Two or three times of applications of EPN were effective regardless of nematode strain and concentration in pot. Efficacy of EPN was different depending on vegetable species. Efficacy was higher on Chinese cabbage, red mustard, and Ssamchoo than that on cabbage, kale, and leaf broccoli. Efficacy of GSN1, Steinernema GSNUS-10, Steinernema CSNUS-14, and Heterorhabditis GSNUH-1 was variable depending on nematode strain, concentration, application times, and vegetable in greenhouse experiments. GSN1 was the most effective and 100,000 infective juveniles per m$^2$(=$1\times10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale in greenhouse.