• Korean journal of applied entomology
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• v.60 no.4
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• pp.463-471
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• 2021

As a tropical plant, the neem tree (Azadirachta indica) has been used for a long time for disease and pest control and medical purposes. In this paper, we reviewed for the active ingredient of neem, the mode of action of azadirachtin in terms of insect growth regulation, repellent, feeding inhibition and oviposition against plant pests. And also we reviewed the current status of practical use in Korea. Among 57 products of neem-based eco-friendly organic agricultural materials distributed in Korea, seven products were certified for their efficacy. The average azadirachtin content of the seven products was 0.38%, which was 5.5 times less than the average content of 2.1% distributed worldwide. In the control effect on neem products in Korea, it showed some variation on aphids, but most showed a control effect of more than 90%. The treatment effects of Lycorma delicatula nymphs were 73-77%, and the control effects for thrips were obtained in the range of 50-72% mortality. The mortality effects against bug and moth species were generally low. It is expected that this review would provide important information necessary for the understanding of distributed neem products and the interpretation of experimental data.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.117-128
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• 2022

In this study, we have examined pyrethroid actions on sodium channels in the pest insect Heliothis virescens. The synthetic pyrethroid permethrin increased steady-state sodium current in H. virescens central neurons and prolonged tail currents (I_Na-tail) due to extreme slowing of sodium channel deactivation. Prolongation of I_Na-tail was evident at permethrin concentrations as low as 60 nM, which modified ~1.7% of sodium channels and 10 μM permethrin modified about 30% of channels. The average time constant (τ₁) of tail current decay was ~335 ms for permethrin-modified channels. These modified channels activated at more negative potentials and showed slower activation kinetics, and failed to inactivate. Permethrin modification of sodium channels was dramatically potentiated by the α scorpion toxin LqhαIT, showing positive cooperativity between two binding sites. The amplitude of the tail current induced by 0.3 μM permethrin was enhanced ~8-fold by LqhαIT (200 pM). Positive cooperativity was also observed between permethrin and the insect-specific scorpion toxin AaIT as 10 nM permethrin potentiated the shift of voltage dependence caused by AaIT (~2-fold).

• Korean journal of applied entomology
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• v.47 no.4
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• pp.447-456
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• 2008

Five effective strains against tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuidae), Steinernema carpocapsae (GSN1), Steinernema sp. (GSNUS-10), Steinernema sp. (GSNUS-14), Heterorhabditis bacteriophora Hamyang (HbH), and Heterorhabditis sp. (GSNUH-1) were selected among 14 isolates of Korean entomopathogenic nematode in laboratory tests. $LC_{50}$ values of above five strains against tobacco cutworm were various by different nematode strains and developmental stages of tobacco cutworm. $LC_{50}$ value of S. carpocapsae (GSN1) was the lowest by $4.0{\sim}8.3$ infective juveniles (Ijs) and 2nd instars of tobacco cutworm was most susceptible. Pathogenicity of five effective strains against tobacco cutworm depends on nematode strain, concentration, and application times. The most effective strain was determined as S. carpocapsae (GSN1). Two or three times of applications were effective regardless of nematode strain, or concentration. Efficacy of S. carpocapsae (GSN1), Steinernema (GSNUS-10), Steinernema (GSNUS-14), and Heterorhabditis (GSNUH-1) was variable depending on nematode strain, concentration, application times, and host variety. S. carpocapsae (GSN1) was the most effective and inoculation of 100,000 infective juveniles per m2 (720,000 Ijs/7.2 $m^2=1{\times}10^9$ 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.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.331-338
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• 2014

Cystatins (CSTs) are reversible and competitive inhibitors of C1A cysteine proteases, corresponding to papain-like cathepsins in plants and animals. A viral CST (CpBV-CST1) was identified from a polydnavirus, Cotesia plutellae bracovirus (CpBV). Our previous study indicated that a transient expression of CpBV-CST1 interfered with immune response and development of Plutella xylostella larvae. To directly demonstrate the protein function, this study produced a recombinant CpBV-CST1 protein (rCpBV-CST1) using bacterial expression system to determine its inhibitory activity against cysteine protease and to assess its physiological alteration in insect immune and development. The open reading frame of CpBV-CST1 encodes a polypeptide of 138 amino acids (${\approx}15kDa$). rCpBV-cystatin protein in BL21 STAR (DE3) competent cells containing a recombinant pGEX4T-3:CpBV-CST1 was over-expressed by 0.5 mM IPTG for 4 h. In biological activity assay, the purified rCpBV-CST1 showed a significant inhibition against papain activity. It inhibited a cellular immune response of hemocyte nodule formation in the beet armyworm, Spodoptera exigua. Moreover, its oral administration retarded larval development of the diamondback moth, Plutella xylostella in a dose-dependent manner. These results suggest that CpBV-CST1 may be applied to control insect pest populations.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.831-841
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• 2017

Different timings of coverage by a small paper bag at the young fruit stage were tested in order to evaluate the effect on the protection of fruit damage occurred by disease or pest, and quality deterioration during organic cultivation of 'Hwasan' (Pyrus pyrifolia Nakai) pear cultivar. The occurrence of four major moth populations and two major diseases in pears were monitored from April to September 2015. Among major moths and diseases, Grapholita molesta and pear rust were found often in the organic pear orchard, and they were observed frequently in May. Coverage by a small paper bag at the young fruit stage resulted in better fruit quality and a higher proportion of commercial fruits compared to a coverage timing of conventional paper bag. Interestingly, the fastest coverage timing of a small paper bag at the young fruit stage (when it was covered in April) showed the lowest occurrence of damaged fruits, which indicates that it successfully protected fruits from the damage caused by moths and diseases during April and May. Moreover, this timing of small paper bag coverage did not negatively affect the major qualitative and quantitative characteristics of fruits. These results suggest that early coverage by a small paper bag at the young fruit stage can be considered an efficient management strategy for organic cultivation of 'Hwasan' pear cultivar.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.445-460
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• 2017

This study was carried out for three years from 2013 to 2015 to investigate the actual condition of pest control of domestic persimmon organically cultivated farmers, to select environment - friendly pest control materials for major pests, and to conduct field test of established control system. The main cultivated cultivar of the reader farmer of organic cultivation was "Buyou" and sprayed organic agricultural material 9~17 times per year for pest control. The most harmful pests were anthracnose, bugs, persimmon fruit worm, and scales, etc. The control materials used were organic lime sulfur mixture, red clay sulfur, emulsifier, bordeaux solution, and self-made plant extracts using garlic, ginkgo nut and pine tree. The effective materials for controlling anthrax were lime sulfur mixture and red clay sulfur. Garlic oil + citronella emulsion, shrubby sophora seed extract + tea extract was effective to control Riptortus clavatus and Euproctis subflava. When installed 60 ea per 10a of mating disruption trap in a sweet orchard, the fruit setting rate was improved by 30%. The results of field test of control system to control 10 times a year in organically grown persimmons were able to harvest fruit of 70.7%. However, since any kinds of pesticides can not be sprayed during the harvest season in September and October, the damaged by bugs did not decreased, and further research is needed.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.251-259
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• 2007

For the development of integrated pest management system by harmonizing biological and chemical control, some experiments wee carried out to select low toxic pesticides against natural enemies. and their residual toxicity were evaluated. Leaf dipping method, body dipping method, and diet treatment method were set up for the toxicity evaluation against Cotesia glomerata adults. We had tested 46 different pesticides (31 insecticides, 11 fungicides, 4 herbicides) at recommending concentration commonly used to control diamond back moth, disease and up-land weeds in chinese cabbage field. Twenty three insecticides, eleven fungicides, and four herbicides were shown to be low toxic to C. glomerata adults in the treatment of body dipping. After insecticide spraying at recommending dose on the chinese cabbage, we examined residual effect of insecticides by introducing natural enemies on different days. Safety interval for the introduction of C. glomerata adults was established according to the residual toxicity of pesticides. Safe insecticides for the introduction of C. glomerata adults at one day after treatment (DAT) were thiacloprid, acephate, chlorfenapyr, clothianidin and at 3 DAT were imidacloprid, deltamethrin, thiamethoxam, dimethylvinphos, emamectin benzoate.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.509-515
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• 1992

Phytophagous insects were surveyed from field populations of Compositae weeds in the order Campanulales. Forty five insect species including unidentified ones of 43 genera in 5 orders and 17 families were recorded from 16 species in 12 genera of Compositae weeds. The hemipterans and coleopterans were the most abundant insects representing 13 and 13 species, repectively. Aphids and leaf beetles were important phytophagous insects on Compositae weeds. The potential biological control insects were Uromelan gobonis and Aethes cnicana on Cirsium japonicum var. ussuriensis and Cryptosiphum artemisiae on Artemisia lavandulaefolia. The leaf beetles, Chrysolina aurichalcea, Longitarsus succineus, Basilepta fulvipes, and Hamushia konishii were often collected from A. lavandulaefolia. Aphids and leaf beetles showed host specificities. The roles of hemipterans collected from the flowers of A. lavandulaefolia and Erigeron canadensis were questionable.

• Korean journal of applied entomology
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• v.40 no.1
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• pp.77-82
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• 2001

Flying behavior during nighttime and control methods of fruit sucking pests were investigated in yuzu (Citrus junos) groves at Koheung area from August to November in 1999. Among the 3 kind of bulbs with different color (white, blue and yellow), white bulb attracted the most number of fruit sucking pests . The 93 percent of the moths was attracted from sunset to 24 o\`clock. Main flying time of hemipteriods in early, mid, and late October were from 22 to 04 o\`clock, sunset to 02 o\`clock and sunset to 24 o\`clock, respectively. Their flying time become earlier as the night temperature declines. For control of fruit sucking pests, attraction liquid traps, light traps (100 W) and illumination light bulb were set up in the yuzu groves (1,000 $\m^2$) from the 1 st October to the 3rd November. Attraction liquid was composed of a raw rice wine 2,000 ml+black sugar 100 g+vinegar 100 ml. When established at 3 sites per 1,000 $\m^2$ orchard, attraction liquid trap reduced the number of sucking spots on yuzu fruit to 64% and its attracting effect maintained for 3 weeks after setting-up. Three light traps per 1,000 m2 which turned on from sunset to 02 o\`clock reduced the number of sucking spots by 60% .

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.35-41
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• 2013

BACKGROUND: In organic agriculture, various cover crops have been used to control weeds. In this study, we investigated the suppressive effects of Vicia tetrasperma (L.) Schred (Eolchigi wandu) on the occurrence of major insect pests and their natural enemies in pepper. METHODS AND RESULTS: To estimate the effect of cover-crop on arthropod diversities and occurrences of insect pest in pepper. V. tetrasperma was sowed as cover-crop plot October, 2008 and 2009. Control plot was kept bare in winter season and mulched with black plastic-film before transplanting red pepper seedlings. Pepper seedlings, Capsicum annuum, were transplanted on the 19th of May, 2009 and on the 20th of May, 2010, respectively. Five Yellow sticky traps were set and changed at 7 days interval. Densities of aphids and thrips and damaged fruit rates by oriental tobacco budworm, Helicoverpa assulta, were counted. CONCLUSION(S): Populations of aphids, thrips and braconid wasps were maintained high on V. tatrasperma before transplanting pepper seedlings and in early season of pepper. However, the densities of aphids on pepper in the control plot were much higher than in the cover-crop plot in the early stage of pepper. Damaged fruit rates by both of thrips and oriental tobacco budworm were not significantly different between the two experimental plots.