• Korean journal of applied entomology
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• v.30 no.2
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• pp.106-110
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• 1991

The mode of inheritance of resistance to fenvalerate in the diamondback moth (Plutella xylostella L.) was studied using insecticide susceptibility and mixed function oxidase tests. Tehre were no differences in the concentration-mortality relationships between $F_1$ progenies $(S_{female}\timesR_{male},\;R_{female}\timesS_{male})$ obtained from reciprocal crosses with the susceptible and fenvalerate-selected strains(R), indicating the absence of sex-linked inheritance. Degree of dominance of the $F_1$ progenies $(S_{female}\timesR_{male},\;R_{female}\timesS_{male})$ were -0.50 and -0.46, respectively, in the insecticide susceptibility test and -0.85 and -0.81, respectively, in the mixed function oxidase test. These results suggest that inheritance of fenvalerate resistance is controlled by and incompletely recessive autosomal gene.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.249-253
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• 1996

In the laboratory study, the toxicities of chlorpyrifos-methyl, chlorpyrifos, etofenprox, etofenprox+PAF' and deltamethrin for different larval instars of S. litura decreased significantly as larvae aged. LCso values for chlorpyrifos- methyl and chlorpyrifos increased significantly from 3rd instar larvae, while those for etofenprox+PAP and deltamethrin-increased from 2nd instar larvae. In pot study, no significant differences in control efficacy were observed among each treated plots and over 90% control efficacy at 5 d after treatment was obtained in all of the treated plots, except treatment with deltamethrin. Therefore four insecticides excluding deltamethrin will be effective for controlling S. litura. However, it will be probably important to select appropriate insecticides and decide a proper time of treatment because the developmental stage is a significant factor in deciding insecticide efficacy because various developmental stages of the tobacco cutworm inhibit in fields.

• Korean journal of applied entomology
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• v.38 no.1
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• pp.53-57
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• 1999

Simple diagnostic kits for monitoring insecticide susceptibility of beet armyworm, Spodoptera exigua (Hiibner) were developed and applied to the field populations. The operation of the kits was based on the correlations between enzyme activities of esterase (EST) and acetylcholinesterase (AChE) and the insecticide susceptibilities. Four different kinds of diagnostic kits (ED, EM, AD, and AM) were designed and classified by diagnostic enzymes (E for esterases and A for acetylcholinesterase) and inhibitors (D for dichlorvos and M for monocrotophos). Diagnostic inhibitor concentrations were 1 mM for ED, 10 mM for EM, 100 mM for AD, and 100 mM for AM. Resistant larvae which were not inhibited by the diagnostic amounts of insecticides developed positive staining (red color), but susceptible~ s howed negative (no color). An insect was used for both EST and AChE diagnostic kits, but different in their samples: hemolymph for EST and the head for AChE. These four diagnostic kits were applied to 1 1 different populations which showed variations of insecticide susceptibilities. Four kits were different in the capability discriminating the insecticide susceptibilites according to insecticides: ED to bifenthrin, AD to methomyl, and ED and AM to chlorpyrifos-methyl. These diagnostic devices can be used for insecticide-resistance management program for this insect pest. It also provide a technical guide to insect pest management for farmers, directors, and researchers.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.348-358
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• 2017

The green peach aphid, Myzus persicae, is one of the most serious insect pest and a vector for a multitude of viral diseases to many crops, vegetables, ornamentals, and fruit trees in the world. A large number of aphids can reduce plant vigor and cause defoliation. Many insecticides have been developed and applied to control the green peach aphid. However, this aphid has displayed a remarkable ability to establish resistance to almost every insecticide. We treated 5 different insecticides registered for M. persicae on pepper leaves and investigated the effects of the insecticides by measuring the time it took to achieve 90% control of the aphids. Acetamiprid worked faster than any other insecticides while cyantraniliprole showed the slowest insecticidal effect. Pymetrozine, pyrifluquinazon, and spirotetramet provided 90% control within similar time. Iwol population's control value was higher than any other populations 24 hours after treatment. When five different unregistered insecticides for M. persicae were treated on pepper leaves, no insecticidal effect was found for gamma-cyhalothrin and novaluron and spinosad showed an insecticidal effect of up to 70% in Iwol population only. Although chlorfenapyr and dinotefuran were not registered for M. persicae, their insecticidal effects were found to be 90% or higher.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.11a
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• pp.12-15
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• 2003

The effects of the non-steroidal ecdysteroid agonist tebufenozide on larvae of C. faviplumus and C. riparius were tested in the laboratory. In the most treatments it reached a statistically significant difference from the control condition. As the concentration of tebufenozide was increased, a relatively larger proportion of the observed mortality was associated with the metamorphosis and molting process. Also, the larval mortality of the first larvae was higher than the fourth-instar larvae in C. riparius. In terms of development, the effects of tebufenozide were delayed growth stage in relatively lower concentration such as 10 $\mu\textrm{g}$/L treatments. Based on the mortality, the susceptibility followed the first-instar C. riparius > the fourth-instar C. flaviplumus > the fourth-instal C. riparius. The morphological effects showed that the first and second segments of body of exposed larvae with tebufenozide expanded slowly and not made a complete cephalothorax of pupae during long times or days. And the head capsule slipped down and forward, revealing a fragile and non-pigmented, unsclerotized new head capsule. There was obvious significant difference in the male/female ratio in contaminated fourth larvae of C. riparius. Also, due to the different emergence periods of male/female in low insecticide concentrations, mating chances or opportunities of insects should be decreased. Accordingly, ecological strategies for keeping of sustainable populations should be disrupted.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.179-186
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• 2017

This study was conducted to monitor the insecticidal susceptibility of western flower thrip, Frankliniella occidentalis, which damage horticultural crops in the Gyeonggi area. Bioassays were conducted under laboratory and greenhouse conditions by using the recommended concentrations of commercial insecticides being used for the control of thrips. Neonicotinoid insecticides, especially acetamiprid (8%) soluble powder (SP), clothianidin (8%) SC, imidacloprid (10%) wettable powder (WP) and thiacloprid (10%) water dispersible granule (WG) were not toxic to F. occidentalis collected from horticultural crops. However, F. occidentalis collected from vegetable greenhouses was extremely susceptible to acetamiprid + spinetoram (6 + 4%) suspension concentration (SC), clothianidin + spinetoram (6 + 4%) SC and methoxyfenozide + spinetoram (6 + 4%) SC, which resulted in over 90% control of thrips. In the greenhouse test, spinetoram (5%) WG, which caused 100% F. occidentalis mortality in the laboratory test, showed 87.4, 88.0, and 98.3% control at 3, 6, and 9 days after treatment, respectively, while imidacloprid (10%) WP showed below 44% control. From the results of this study, spinosin insecticides, such as more than over 4 and 10% of spinetoram and spinosad, and pyrrole insecticide, such as 5% chlorfenapyr, are recommended for the effective control of F. occidentalis.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.320-330
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• 2007

Mitochondrial 16S DNA sequences of Bemisia tabaci which were collected on rose greenhouse of Iwol and Jinchen in Chungbuk and red pepper field of Miryang, Gyeongnam, were analyzed. The mtCOI PCR product of B. tabaci collected on red pepper field of Miryang were digested with EcoT14I (Sty I) into two fragments 555bp and 311bp, while the PCR product of B. tabaci collected on rose greenhouse of Iwol were digested with Sty I into two fragments of 560bp and 306bp. As a result, B. tabaci collected on red pepper reveal biotype Q and those on rose greenhouse was biotype B. These was difference between two biotypes in insecticide susceptibility, and the biotype B was more susceptible than biotype Q. As a result of foliar systemic test, root-uptake systemic test and residual effect, the biotype B was more susceptible. In case of inhibition effect on enzyme activities of fenitrothion (organophosphorous) and fenothiocarb (carbamate), those of biotype Q was higher than those of biotype B. These results indicate that biotype Q was more resistant than biotype B against 12 insecticides.

• Korean journal of applied entomology
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• v.55 no.3
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• pp.257-266
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• 2016

Subtropical insect pests expand their habitats by migration to temperate zones along with global climate change. A subtropical insect pest, Maruca vitrata, is infesting leguminous crops including azuka beans in Korea and gives significant economic damages. Its great genetic variation raised an issue of the origin of a Korean M. vitrata population. To understand the genetic character of the Korean population, its cytochrome oxidase subunit 1 (cox 1) gene was sequenced and phylogenetically analyzed with other regional populations. The world populations of M. vitrata were grouped into three clusters: Asia-African, American, and Oceanian. The Korean population was classified into Asia-African cluster. To characterize the insecticide susceptibility of the Korean population, seven different insecticides (4 neutoxic insecticides, 1 insect growth regulator, 2 biopesticides) were assessed. Young larvae of M. vitrata were relatively susceptible to all tested insecticides. However, old larvae were much less susceptible than young larvae. No test insecticides effectively (> 50%) killed the old larvae of M. vitrata within 7 days.

• Korean journal of applied entomology
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• v.52 no.1
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• pp.35-43
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• 2013

All tested Korean populations of the diamondback moth, Plutella xylostella, are known to be resistant especially against pyrethroid insecticides by mutation in its molecular target, para-sodium channel. Moreover, P. xylostella is able to develop resistance against most commercial insecticides. This study was performed to develop an efficient control technique against P. xylostella by a combined treatment of an endoparasitoid wasp, Cotesia plutellae, and a microbial insecticide, Bacillus thuringiensis. To investigate any parasitism preference of C. plutellae against susceptible and resistant P. xylostella, five different populations of P. xylostella were compared in insecticide susceptibilities and parasitism by C. plutellae. These five P. xylostella populations showed a significant variation against three commercial insecticides including pyrethroid, organophosphate, neonicotinoid, and insect growth regulator. However, there were no significant differences among five P. xylostella populations in their parasitic rates by C. plutellae. Moreover, parasitized larvae of P. xylostella showed significantly higher susceptibility to B. thuringiensis. As an immunosuppressive agent, viral ankyrin genes (vankyrins) encoded in C. plutellae were transiently expressed in nonparasitized larvae. Expression of vankyrins significantly enhanced the efficacy of B. thuringiensis against the third instar larvae of P. xylostella. Thus an immunosuppression induced by C. plutellae enhanced the insecticidal efficacy of B. thuringiensis. These results suggest that a combined treatment of C. plutellae and B. thuringiensis may effectively control the insecticide-resistant populations of P. xylostella.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.225-231
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• 2003

The susceptibility of the different larval stages of Spodoptera litura to nine insecticides was evaluated using the perilla leaf-dipping method. Median lethal concentration ($LC_{50}$) was increased with larval development in the range of 0.5 ppm to 5.6 ppm, 9.9 ppm to 27.9 ppm, 9.6 ppm to 125.1 ppm and 24.3 ppm to 546.6 ppm in the 1st, 2nd, 3rd and 4th instar, respectively. The tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC/ sub 90/) to the recommended concentration, was 0.04 to 0.8 in the 1 st, 0.2 to 7.5 in the 2nd, 0.7 to 115.3 in the 3rd and 1.2 to 485.4 in the 4th instars. Lower D$LC_{50}$ and DTR, which is the difference between the $LC_{50}$ and the TR of 4th and other instars, respectively, were observed in chlorfenapyr, chlorpyrifos and EPN while higher ones were lufenuron, chlorfluazuron and teflubenzuron. These results mean that insecticides with lower D$LC_{50}$ and DTR are effective in controlling larva of S. litura collected in Milyang, Korea.