• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.27-32
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• 1986

To establish a method for measuring varietal resistance against rice stem maggot in field and pot, 20 varieties were used in $1981{\sim}1983$. The degree of injured stems by the 1st generation larvae was significantly correlated with that of injured panicles by the 2nd ($r=0.864^{**}$). There was no ovipositional preference in rice stem maggot. The larval mortality after artificial infestation varied widly from 5.6 to 100% in varieties and that of the resistant varieties was high after boring. There was a negative correlation between number of injured leaves and larval mortality after artificial infestation ($'81:r=-0.833^{**},\;'82:r=-0.918^{**}$). It is considered that larval mortality mainly caused by antibiosis and larval mortality 20 days after infestation on rice seedlings is ideal for evaluating the varietal resistance to rice stem maggot. Resistant varieties are Nagdongbyeo, Jinjubyeo and Chucheongbyeo susceptible varieties, Keumgangbyeo, Milyang 23, Baigyangbyeo and Milyang 30.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.411-418
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• 2013

The black pine bast scale, Matsucoccus thunbergianae is one of the most serious insect pest in Japanese black pine, Pinus thunbergii forest in Korea. Insecticidal activity of 10 folds hot water extracts from 7 herbal plants (Atractylodes lancea, Eugenia caryophyllata, Lonicera japonica, Melia azedarach, Quisqualis indica, Sophora flavescens and Taraxacum mongolicum) were tested against different stage of M. thunbergianae using spray method both in laboratory and field. Efficacies of herbal extracts were different depending on stage of M. thunbergianae. Q. indica sprayed with hand sprayer produced the highest corrected mortality of 95.7% on intermidiated nymph stage, however, A. lancea produced the highest corrected mortality (51.3%) on pupae of M. thunbergianae in laboratory. Q. indica and A. lancea were highly effective against female M. thunbergianae in laboratory, however, corrected mortality was lower than other stage (40.0%). Efficacy of Q. indica was similar to effective insecticide, fenitrothion 50% EC against M. thunbergianae in field trials. These results indicated that Q. indica could be an environmental friendly control agent of M. thunbergianae.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.141-150
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• 2015

Thirty-two actinomycetes isolates from Korean forest soil were screened for their nematicidal and reproduction suppression activity against pine wood nematode (PWN) which is widely spread in Korea. Culture filterates of 21 isolates showed more than 90% mortality at 2-fold concentration. Among them, AM210, SG16, YD116 and YD315 were more effective than others on reproduction of PWN. The YD116 isolate was identified as Streptomyces atratus by morphological and 16S rDNA analyses. Hydrazine hydrate, similar to hydrazidomycin which has cytotoxicity among substances from S. atratus against PWN, was tested for its nematicidal activity. Ten ppm of the hydrate showed 60.8% mortality. Additional studies are needed for practical use of the S. atratus YD116 isolate.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.351-356
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• 2017

For determining the insecticidal effect of Carbofuran on the Brown planthopper, Nilaparvata lugens, sucking toxicity by drenching application, sucking and contact toxicity by leaf dipping application, and contact toxicity by topical application were examined. Drenching caused two types of mortality patterns. One was logarithmic curve at a relatively high concentration (8~30 ppm) with over 40% mortality in 24 h, and the other was an S-shaped curve at low concentrations (1~4 ppm) with over 60% mortality on the fifth day after Carbofuran treatment. Leaf dipping application caused a rapid increase in mortality in a day, and this effect decreased steadily with time. Topical application showed steep increase in mortality in a day, and hardly increased thereafter. The best mortality evaluation time for the drenching application was the second day (42 h), and that for the leaf dipping and topical applications was the first or second day after Carbofuran application. When the insecticide has systemic effects, drench application provides the best efficacy and its insecticidal effects persist for a longer time than any other application method.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.129-134
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• 2015

White grub damages various crops, trees and they can also be one of the most serious pests of turf grass in golf courses. This study was conducted to determine the biocontrol of white grubs with 18 different kinds (anise, camphor, castor, cinnamon, clove oil, citronella, fennel, geranium, lavender, lemongrass, linseed, neem, peppermint, pine, rosemary, tea-tree, thyme, and turpentine) of plant essential oils in laboratory, green house and field. Anise oil (88.9%), linseed oil (100%), and tea-tree oil (88.9%) were highly effective among tested essential oils against 3rd instar of Bifurcanmala aulax in cap vial experiment. However, anise and linseed oils showed low mortality against $3^{rd}$ instar of Popillia japonica in pot greenhouse experiment. Efficacy of anise, linseed oil, and tea-tree was also different depending on target white grub in field trials. Correlated mortality showed 32.6% only in tea-tree oil treatment against pupae of Adoretus tenuimaculatus however, correlated mortality of anise, linseed and tea-tree oil were 54.8, 51.6 and 56.5% respectively against $3^{rd}$ instar of Exomala orientalis in the field trial in Adelscott Country Club in Hapcheon, Gyeongnam province.

• 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.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.27-32
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• 2013

Damage of tea bagworms, Eumeta minuscula was observed for the first time from grape leaves of grape (varieties: Cambell Early and M.B.A.) from a vinery at Gumho-up, Gyeongsan, Gyeongbuk on 31 August, 2012. Activity of insecticides [Bacillus thuringiensis var. kurstaki (serotype IIIa, IIIb) WP, chlorantraniliprole 5% GP, methoxyfenozide 21% SC, spinetoram 5% GP, and spinosad 10% GP] was tested on fourth instar larvae of Eumeta minuscula in laboratory. Mortality of 4th instar of Eumeta minuscula was higher when treated with spinosad 10% WG (88.7%) and spinetoram 5% WG (67.7%) sprayed with field recommended concentration using a home sprayer in laboratory. Mortality decreased as the concentration decreased, however leaf damage rate was significantly different between the one-fourth rate and the control. Spinetoram 5% WG and spinosad 10% WG showed 63.7 and 55.7% respectively mortality of fourth instar Eumeta minuscula in field. Though these two insecticides could be used for the control of bagworms on grape, a more effective insecticide needs to be found.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.236-242
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• 2008

Laboratory and greenhouse experiments were conducted to evaluate the effect of root zone application of some systemic insecticides for control of the brown planthopper (BPH), Nilaparvata lugens, as one of the management option to minimize the adverse effects and maximize the efficacy of insecticide application. Five systemic insecticides, namely, carbofuran, carbosulfan, diazinon, ethoprophos and imidacloprid, as granular formulation were placed in the root zone and measured the mortality, fecundity, and nymphal survivorship of the planthopper. Diazinon and ethoprophos did not show the significant mortality of the BPH. When the BPH were inoculated at the day of carbofuran treatment, adult mortality was shown almost 100% at seven days after treatment and BPH nymphs were remained very few on rice at 25 days after treatment. When carbofuran were placed 10 days before the BPH inoculation, it showed almost 100% adult mortality after one day, and no nymphs were found until 25 day after inoculation. Efficacy of carbofuran on BPH when applied in 10 day-old rice was higher than in 30 day-old rice. These results indicated that the root zone application of carbofuran can control N. lugens effectively with less adverse effect to the natural enemies inhabited on rice plants.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.113-121
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• 2002

This study investigated the changes in the fitness of brown planthopper, NilapaHata lugens, to several rice varieties with different resistance background, after multi-generational selection on a resistant rice variety. A susceptible strain of brown planthopper (Dongjin-5) had been reared on the Chungchungbyeo with Bph1 resistance gene for three generations (Chungchung-G3) and six generations (Chungchung-G6), then the fitness change was evaluated by measuring their longevity, fecundity, preferences, and survivorships on the varieties with various background of resistance. After being selected three to six generations on Chungchungbyeo, feeding preference, adult longevity, and fecundity increased, where as nymphal period reduced when they were reared on various varieties with Bph1 gene. The egg Periods were not much different among the varieties fed on, except for the Chungchung-G6 on the rice varieties of Milyang63 (bph2 gene) and Gayabyeo (Bph1+bph2 gene). These results suggest that the susecptible Donajin-5 (Biotype-1) can be easily converted to a resistant biotype-2 capable of overcoming the resistant varieties with Bph 1 gene.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.1-6
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• 2007

Entomopathogenic nematodes (Heterorhabditis sp. Gyeongsan strain, Steinernema carpocapsae GSN1 strain, S. feltiae Monteri strain, S. glaseri Dongrae strain, S. longicaudum Nonsan strain and S. monticolum Jiri strain) were evaluated for the environmentally sound control of sawfly, Arge captiva, A. pagana pagana and A. similis in the laboratory and pot. The corrected mortality of 3rd instar of Arge captiva larva was 100% at 5 days after treatment with S. carpocapsae GSN1 strain and S. feltiae Monteri strain in Petri dish. The mean numbers of established infective juveniles (Ijs) of S. glaseri Dongrae and S. carpocapsae GSN1 strain in a Arge captiva larva were 10.2 and 4.2 Ijs/larva, respectively. Pathogenicity of S. carpocapsae GSN1 strain was different larval stage, i.e., $LC_{50}$ value of S. carpocapsae GSN1 strain against 2nd, 3rd and 4th instar of A. pagana pagana was 11.5, 9.3, and 8.4 Ijs, respectively. Mortality of Arge captiva, A. pagana pagana and A. similis were 72.5, 85.0 and 85.0% by S. carpocapsae GSN1 strain at the $2{\times}10^9Ijs/ha$, respectively, in the pot.