• Korean journal of applied entomology
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• v.47 no.4
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• pp.369-378
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• 2008

After treatment with imidacloprid, there were clear differences in the time to the first reaction of Myzus persicae among the concentrations treated. The time taken for the proboscis of the aphids to penetrate, during the recording plants increased as the imidacloprid concentration increased. Imidacloprid concentration inflow into a leaf was investigated using high-performance liquid chromatography, and the residues of the imidacloprid varied slightly with the different concentrations treated. However, the inflow rates of this insecticide into a leaf increased as the dipping times increased. Furthermore, it was shown that there was no relationship in inflow concentration between the concentrations and times of treatment. However, the concentration in the leaf differed according to the dipping time. Judging from the fact that the first reaction behavior against imidacloprid displayed at an inflow concentration of 0.32-0.35 mg/L, we concluded that inflow concentrations causing the first reaction of the aphids to the insecticide were much lower than the concentration treated. The general feeding characteristics of the aphids indicated that xylem and/or phloem feeding behavior continued after a series of probing behaviors and stylet activity during the first 3 h from the start of EPG recording. After 90 min treatment with imidacloprid, feeding behavior over the next 30 min indicated a significant increase in the withdrawal of the stylet from the plant at all treated concentrations. Xylem and/or phloem feeding patterns were significantly decreased during this time. In particular, the proportion of xylem feeding differed according to the concentration of imidacloprid.

• 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.

• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.199-202
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• 2007

This study was carried out to provide pest control information for the cultivation of Eleutherococcus senticosus Max. As a result of investigation of the diseases and insect pests, three pathogens and three insect pests were identified from the field sample, respectively. The identified insects pests were aphids, stinkbugs and Bothrogonia japonica. Occurrenre peaks of aphids were occurred on June and August, and generally young leaves and flower buds were injured mainly. The identified diseases were black ring spot caused by Phoma sp., gray mold caused by Botrytis cinerea and leaf blights caused by Rhizoctonia solani. The black ring spot was the most severe disease and was investigated from the beginning of June, and the incidence of the disease was 30% higher than that on September. As a result of growth test under different temperature conditions on PDA, these pathogens showed the best mycelial growth rate between 25 $^{\circ}$C and 30 $^{\circ}$C, and these results indicate that these diseases occur on hat summer season.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.256-265
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• 1995

The effect ground-cover weeds on the occurrence of apple pests and their natural enemies was studied in an apple orchard in Ahnsung, Kyung-gi do during seasons of 1993 and 1994. The major apple pests and their parasitoids and predators were surveyed on the apple tree canopy in tow experimental plots; a weed-free lot where all weeds were removed by herbicide treatment, and a mowed plot where weeds were allowed restrictly by cutting with an asickle. Also, a sweep net sampling was taken from ground-cover weeds in the mowed plot. There were no significant differences in the abundance of mite and aphids between two plots, although mite densities tend to be lower in the mowed plot. The apple leaf miner, Phyllonorycter ringoniella, was significantly fewer in the mowed plot,. The densities of natural enemies of mites and aphids were slightly higher in the mowed plot. The parasitism of apple leaf miner in the mowed plot was 6~10% and 20~25% higher than that in the weed-free plot in 1993 and 994, respectively. Several natural enemies such as Apanteles kuwayamai (Braconidae), Orius sauteri (Anthocoridae), Chrysopa sp. (Chrysopidae), coccinellidae, and Eulophidae were collected both from weeds and the apple trees, However, potential apple pests were not observed on weeds. The development of insect community on the apple tree canopy was restricted by the pesticide spray on apple trees, while the insect community on weeds was maintained without significant destruction by pesticides spray on apple trees. Consequentely, the ground-cover weeds under apple trees affected occurrences of apple pests and their natural enemies in apple trees. te specialist natural enemies such as apple leaf miner's parasitoids dispersed from weeds to the apple canopy and affected apple leaf miner density significantly. However, generalist predators that have preys available on weeds stayed on weeds, hence their control effects for mites and aphids on the apple canopy were low.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.479-483
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• 2014

The area of greenhouse horticulture has increased dramatically since the early 1990s in Korea. However, area per farmer still very small and diverse pest species occurs in greenhouse abundantly because of its protected condition. To manage pests, farmers use many pesticides frequently. Incessant and improper use of chemicals provoked pesticide resistance in pest and poisoning of farmers. In this study, we investigated the efficiencies of automatic dry fog sprayer for controlling two aphid species, Aphis gossypii and Myzus persicae, in greenhouse horticulture. When doors and side windows were completely closed in automatic dry fog sprayer treatment greenhouse, aphids were controlled similar level with conventional spraying method (percent control: 61.0~94.1%). However, when half of the doors and side windows of the greenhouse were opened, aphids were controlled poorly (percent control: 36.0~54.4%).

• Korean Journal of Agricultural Science
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• v.28 no.1
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• pp.18-26
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• 2001

Application of the Asian ladybird (Harmonia axyridis) to control several species of aphids in the plastic green houses in mind, control effects of aphid populations regulated by the Asian ladybird were observed. The green peach aphid, the turnip aphid, and the cotton aphid were present on mustard plants, Angelia utlis, ornamental kales, and egg plants at greenhouses in spring, summer, and winter. Adults and larvae of the Asian ladybird used in experiments were collected from aggregated sites at Taejon in the autumn and reared on the cotton aphid in the laboratory. In winter, more number of adults and larvae of ladybirds than in other seasons were needed to control aphid population in successively double plastic greenhouses with supplied subterranean water for keeping warmth. In spring and summer, it was possible to keep the aphid populations low when necessary by manipulating ladybird populations according to the density of aphids. On the other hand, the innate increasing rate of aphid, the aphid population density at the time of applying ladybird, the predacious ability of ladybird at specific developmental stages, and needed periods should be taken into account to control aphids. In addition, the environmental factors, for example, optimum temperature and humidity should be considered to be biologically effective when ladybirds are released to greenhouses.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.217-226
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• 2006

As the results achieved by the evaluation of toxicities on an aphid parasitoid, Aphidius colemani by 79 pesticides registered as horticultural pesticide and 4 adjuvants far pest control, 6 insecticides including a-cypermethrin, 13 fungicides including metalaxyl-M+mancozeb and 4 acaricides including bifenazate showed low toxicity against A. colemani adult. Low toxicity was showed in all the 4 adjuvants as well. In residual toxicity test from 40 pesticides which showed toxicity more than 50%, A. colemani was safe from 11 pesticides from the 3th day after treatment, 7 pesticides from the 5th day after treatment and 14 pesticides from the 7th day after treatment, respectively. But, chlorpyrifos-methyl, diflubenzuron+chlorpyrifos, etofenprox+diazinone and imidachloprid+chlorpyrifos showed high toxicities reaching 100%, 97.7%, 100% and 100% respectively, even from the 7th day after treatment. To evaluate the control effect by A. colemani against Myzus persicae in a greenhouse, A. colemani was released at parasitoid versus aphids rates of 1:50 and 1:100 when the population of M persicae was 50 per plant. After release, aphids population remained steady for 20 days after release at the level of around 60 aphids per plant. During the investigation, insecticides fur thrips control and fungicides for powdery mildew control were treated, but didn't affect the mummy forming of A. colemani. It may be suggested from these results that the selected insecticides, fungicides, acaricides and adjuvent could be incorporated into the integrated M. persicae management system with A. colemani on greenhouse cultivation.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.83-88
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• 1987

Differences in susceptibility of several organophosphate, carbamate and pyrethroid insecticides to three species of aphids were determined by leaf-dipping and spray methods. The insects tested were the apterous adults of the green peach aphid (Myzus persicae), cotton aphid (Aphis gossypii) and soybean aphid (Aphis glycines). The comparison of $LC_{50}$ levels was indicated as follows; (1) The susceptibility to insecticides tested were greatly varied with the test methods. (2) The leaf dipping method is more recommendable than the spray method for insecticide screening with aphids. It was easier, more accurate and less variable than the latter. (3) The susceptibility to insecticides was greatly varied between the aphid species. Soybean aphid was more susceptible to the insecticides than green peach aphid and cotton aphid. Exceptionally, pirimicarb was not effective on the cotton aphid.

• Korean journal of applied entomology
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• v.60 no.3
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• pp.305-312
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• 2021

This study was carried out to investigate insect pests and their damage caused to commercial amaranth in Gangneung, Gangwon-do, Korea, during 2019-2020. A total of seven families and 18 species were identified including three species of aphids, twelve species of stink bugs, and four species of moths. Among them, five species caused significant economic damage due to a large number of occurrences; Aphis fabae, Nysius plebejus, Polymerus cognatus, Spoladea recurvalis and Spodoptera exigua. Aphids started to occur from the end of April, and showed the greatest incidence in early June. Three Nysius species occurred from mid-May and showed the maximum density in late August, and then its population decreased from the beginning of September. Two species of moth caterpillars began to occur from mid-August and damaged amaranth until mid-October. Comparing the yields between amaranth plants with and without a spray of pesticides for each pest, the yield loss of seed by aphids and stink bugs were 51.9% and 69.8%, respectively. Also, the reduction rates of leaf biomass by S. recurvalis and S. exigua were 72.5% and 36.5%, respectively.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.339-355
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• 2021

Aphids can damage plants directly by absorbing their phloem sap and indirectly by transferring plant viruses and causing sooty mold. We compared the thermal effect on the development, survivorship, and reproduction of four cereal crop-damaging aphid species, Rhopalosiphum padi, Aulacorthum solani, Aphis craccivora, and Acyrthosiphon pisum using a life table analysis method. We investigated the stage-specific development period, survivorship, adult longevity, and fecundity of the above mentioned four aphids at 10, 15, 20, 25, and 30℃, respectively, and analyzed their life table parameters using the age-stage, two-sex life table analysis. A. solani nymphs could not complete their development to adulthood at 30℃. The intrinsic increase rate of R. padi was the highest at all tested temperatures except for that at 15℃ (0.12, 0.34, 0.47, and 0.32 at 10, 20, 25, and 30℃, respectively), and that of A. pisum displayed negative values at 30℃ (-0.04). It is speculated that R. padi would be a dominant species under high temperature conditions and A. solani is a highly adaptive species at low temperatures through the comparative analysis of the life table parameters of four aphid species damaging to cereal crops.