• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.65-70
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• 1975

The study was planned to detect resistance levels of striped rice borers (Chilo suppressalis Walker) and green rice leafhoppers(Nephotettix cincticeps Uhler) from different localities to organophosphate and carbamate insecticides using topical application. Strains of overwintering striped rice borers were collected from 7 different areas in Gyeonggi Province and they were kept under conditions of about $25^{\circ}C$ for 10 days. Overwintered and reared larvae of striped rice borers were compared for response to insecticides. The strains of green rice leafhopper were collected from Iri, Milyang, Pyongtaek, Echeon and Suweon. Insects were multiplied in the lab. All insecticides tested were organphosphates(MPP, MEP and Diazinon) and carbamate (NAC), which have been used in control of rice insect pests for over past 10 years. The results obtained were as follows; a. With MPP compound, resistant levels of the Joam, Suweon, and Echeon strains of C. suppressalis were from 2 to 4 times as compared with the Yangpyong strain. b. With MEP insecticide, resistant levels of the Kimpo, Pyongtaek, Yongin, Echeon, Suweon, and Joam strains of C. suppressalis were from 2 to 6 times as compared with the Yangpyong strain. c. With Diazinon, resistant levels of the Suweon strain of C. suppressalis were 3 times greater than the Yangpyong strain; but the resistant levels of Kimpo, Pyongtaek, Yongin, and Echeon strains approximated the later. 4. The overwintered larvae of C. suppressalis were more tolerant to the insecticides than the larvae reared in the lab. e. With MEP, resistant levels of the Iri, Milyang, and Pyongtaek strains of N. cincticeps to the Suweon strain showed 13, 8, 7 and4 times, respectively. f. With MPP, resistant levels of the Iri and Pyongtaek strains of N. cincticeps were 7 and 4 times as compared with the Suweon strain, respectively. g. With NAC, resistant levels of the several strains of if. cincticeps showed no difference, and seemed not to have developed resistance yet.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.380-390
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• 2005

This study was carried out for looking into the status of susceptibility of vinyl house insect pests to insecticides. The Thrips (Thrips palmi and Frankliniela occidentalis), Mites (Tetranychus urticae), Aphids (Aphis gossypii) and Whitefly (Trialeurodes vaporariorum) were captured at various areas where the host crop was being cultivated and the susceptibility level of each pest insect was investigated. The susceptibility of each pest insect varied by insect species and areas where they were caught. The tested insecticides showed good control effect to palm thrips in 2000, but in 2003 showed decrease of effect to them. Western flower thrips showed low susceptibility to neonicotinoids, imidacloprid and thiamethoxam, but high to chlorfenapyr, spinosad, emamectinbenzoate and fipronil. Antibiotic insecticides, abamectin and milbemectin, and chlorfenapyr were very effective on mite control and dicofol still had good effectiveness to it despite of long year use. No aphid species showed resistance to pyrethroid and carbamate insecticides. Relatively new insecticides such as imidacloprid, spinosad, pymetrozine were effective to whitefly, but not were organophosphates, carbamates and pyrethroids.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.64-70
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• 2013

The greenhouse whitefly, Trialeurodes vaporariorum, is an economically important pest for greenhouse crops because they cause direct damage by feeding on plant nutrients and indirect damage as transmits many virus vectors. It has recently become a serious problem because of the continuous use of insecticide resulting in resistance among greenhouse whitefly population. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of nymph greenhouse whitefly were investigated. Isolated fungus was identified as Isaria fumosorosea by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin, and EF1-${\alpha}$ regions. This fungus was named as I. fumosorosea SDTv and tested for the virulence against nymphs T. vaporariorum and the cold activity, the thermotolerance and the stability of UV-B irradiation on conidia. Mortality rate of greenhouse whitefly showed from 84 to 100% and the virulence increased with increasing conidial concentrations, $1{\times}10^5$ to $10^8$ conidia/ml. Conidia were stable at $35^{\circ}C$, 0.1 $J/cm^2$ of UV irradiation and germinated after 8 days at $4^{\circ}C$. Additionally, the activities of chitinases and proteases produced by I. fumosorosea SDTv were varied according to the medium. In conclusion, I. fumosorosea SDTv which showed high mortality rate against greenhouse whitefly will be used effectively in the integrated pest management programs against the greenhouse whitefly.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.253-261
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• 2009

For the environment-friendly control of beet armyworm, Spodoptera exigua, in spring onion fields, we have examined an alternative application method. Twenty-five insecticides registered for spring onion were tested for control effect against the beet armyworm in the laboratory, then the best 9 chemical and a single biological insecticides were selected and compared with 2 new isolates of Bacillus thuringiensis in a polyvinyl house. After that, 4 chemical and 3 B. thuringiensis treatments were used in the field for the control of beet armyworm in the spring onion. Two application methods are used: one is triple treatments with the same chemical and the other is alternative application with different chemicals and B. thuringiensis for 7 days intervals. Indoxacarb WP - chlorfluazuron EC - B.t. var. kurstaki CAB141 and indoxacarb WP - methoxyfenozide + spinosad SC - Chlorfluazuron EC - B.t. var. aizawai CAB109, B.t. var. kurstaki CAB141 showed greater than 78% mortality of beet armyworm larvae and greater than 43% damage decrease in spring onions infested by beet armyworm. These results showed that alternative applications had higher control effect than any other applications. It was suggested that alternative applications with microbial biological agents such as B. thuringiensis might minimize the development of insecticide resistance and might be used as the environment-friendly control of the beet armyworm.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.199-205
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• 2000

The field control efficacy of entomopathogenic nematode, Steinernema carpocapsae Weiser, was evaluated on the beet armyworm, Spodoptera exigua (Hiibner). The insect pest has been known to be a defoliator at the aerial part of the crop and difficult to be controlled effectively with most commercial chemical insecticides due to its insecticide resistance. To overcome the susceptibility of the nematodes to desiccation when they were applied by leaf spray in field condition, we screened several commercial antidesiccants (alkyl glucoside, CMC, glycerol, Keltrol-F, Kunipia-G, and Laponite LXG) optimal for survival of the nematodes. Keltrol-F (0.1 %) was selected as a candidate supplement for field application of the nematodes. Leaf spray of the nematodes at 5,000 infective juveniles/ml of distilled water containing 0.1 % Keltrol-F resulted in 87.7% control efficacy on the 3rd instar larvae of Sp. exigua.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.24-29
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• 1993

Experiments were conducted to study effects of different bioassay methods on toxicity to the German cockroach (Blattella germanica L.) ith six insecticides. For male adults, by dry film method, the {TEX}$LC_{50}${/TEX} value of chlorpyrifos. fenvalerate, propoxur, permethin, DDVP, and hydramethylnon was 1.79, 1.87, 3.04, 4.37, 32.72, and 270.81 ppm, respectively and the same tendency was shown in the female. For male adults, by topical micro-application method, the {TEX}$LD_{50}${/TEX} value of DDVP and fenvalerate, chlorpyrifls, permethrin, propoxur, hydramethylnon was 2.63, 3.79, 4.51, 6.73, 44.99 $\mu\textrm{g}$/g, respectively and the same tendency was shown in the female. From the diet toxicity method against male adults, the CT value (Concentration%$\times${TEX}$LT_{50}${/TEX}) showed that chlorpyrifos was rapid effective and hydramethylnon was residual effective.

• The Korean Journal of Pesticide Science
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• v.6 no.2
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• pp.80-86
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• 2002

The activities against Frankliniella occidentalis adults collected at rose greenhouse of 40 commerical insecticides were investigated. Among them 9 insecticides showed over 80% mortality to the adults; chlorfenapyr, chlorpyrifos- methyl, emamectin benzoate, fenthion, fipronil, phenthoate, spinosad, chlorpyrifos+diflubenzuron and furathiocarb+diflubenzuron. Susceptibility of field populations collected from greenhouse rose at 5 locations in 2001 was evaluated against the 9 insecticides selected. There was considerable difference in susceptibility depending on the treated insecticides and the regions from which the populations were collected. Goyang and Gimhae populations showed lower $LC_{50}$(ppm) values then Imsil, Jincheon and Gaangjin populations to all the tested insecticides. The adults of all field populations showed lower $LC_{50}$ values less than 1 ppm to emamectin benzoate, fipronil and spinosad. From these results, we could recommend 5 insecticides, such as emamectin benzoate, fipronil, spinosad, chlorpyrifos+diflubenzuron and furathiocarb+diflubenzuron as effective ones to control the Frankliniella occidentalis field populations.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.265-270
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• 1993

The German cockroach(Blattelia germanica) population~ were successIVely selected with ch\orpyrifos and permethrin during the six generations. The resulting resistant $R_{chtorpenfos}$(Rc) and $R_{permethnn}$(Rp) stra.ins were studied to investigate the esterase activity by spectrophotometer, filter parper test, and electrophoresis. Esterase-$\alpha$ activities by filter paper test showed 2.65 and LBZ times higher in the Rc and Rp strains than the susceptible strain, respectively. ln the spectrophoLometer method, the esterase activit18s to $\alpha$-and $\beta$-naphthyl acetate were increased 2.34 and 5.28 times in the Rc than susceptible strain, and 1.48 and 2.92 times in the Rp Limn susceptible stram, respectlvely. Zymogram patterns of eslerase isozyme by agarose gel electrophoresis showed totally five bands. The Rc and Rp strains showed two additive bands as, Est-2 and Est-3, which were not shown in the susceptible strain. but the Rp strain dId not show Est-5 bands which was COlumon in the Rc and susceptible strams.

• Mycobiology
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• v.42 no.4
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• pp.385-390
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• 2014

The beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) is difficult to control using chemical insecticides because of the development of insecticide resistance. Several pest control agents are used to control the beet armyworm. Entomopathogenic fungi are one of the candidates for eco-friendly pest control instead of chemical control agents. In this study, among various entomopathogenic fungal strains isolated from soil two isolates were selected as high virulence pathogens against larva of beet armyworm. Control efficacy of fungal conidia was influenced by conidia concentration, temperature, and relative humidity (RH). The isolates Metarhizium anisopliae FT83 showed 100% cumulative mortality against second instar larvae of S. exigua 3 days after treatment at $1{\times}10^7$ conidia/mL and Paecilomyces fumosoroseus FG340 caused 100% mortality 6 days after treatment at $1{\times}10^4$ conidia/mL. Both M. anisopliae FT83 and P. fumosoroseus FG340 effectively controlled the moth at $20{\sim}30^{\circ}C$. M. anisopliae FT83 was significantly affected mortality by RH: mortality was 86.7% at 85% RH and 13.4% at 45% RH. P. fumosoroseus FG340 showed high mortality as 90% at 45% RH and 100% at 75% RH 6 days after conidia treatments. These results suggest that P. fumosoroseus FG340 and M. anisopliae FT83 have high potential to develop as a biocontrol agent against the beet armyworm.

• Mycobiology
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• v.42 no.4
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• pp.346-352
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• 2014

Recently, the Q biotype of tobacco whitefly has been recognized as the most hazardous strain of Bemisia tabaci worldwide, because of its increased resistance to some insecticide groups. As an alternative control agent, we selected an Isaria javanica isolate as a candidate for the development of a mycopesticide against the Q biotype of sweet potato whitefly. To select optimal mass production media for solid-state fermentation, we compared the production yield and virulence of conidia between 2 substrates (barley and brown rice), and we also compared the effects of various additives on conidia production and virulence. Barley was a better substrate for conidia production, producing $3.43{\times}10^{10}$ conidia/g, compared with $3.05{\times}10^{10}$ conidia/g for brown rice. The addition of 2% $CaCO_3+2%$ $CaSO_4$ to barley significantly increased conidia production. Addition of yeast extract, casein, or gluten also improved conidia production on barley. Gluten addition (3% and 1.32%) to brown rice improved conidia production by 14 and 6 times, respectively, relative to brown rice without additives. Conidia cultivated on barley produced a mortality rate of 62% in the sweet potato whitefly after 4-day treatment, compared with 53% for conidia cultivated on brown rice. The amendment of solid substrate cultivation with additives changed the virulence of the conidia produced; the median lethal time ($LT_{50}$) was shorter for conidia produced on barley and brown rice with added yeast extract (1.32% and 3%, respectively), $KNO_3$ (0.6% and 1%), or gluten (1.32% and 3%) compared with conidia produced on substrates without additives.