• Korean journal of applied entomology
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• v.7
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• pp.5-13
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• 1969

Present system of seed potato production in Korea has several weak points and consequently has difficulties in covering annual shortage of 60,000 tons of seed potatoes. The author has an opinion that this so called 'High land system' of seed potato production adopted by the Government should be replaced by the 'Coastal area system' which is proposed by the author and has many advantages over present 'High land system'(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages. the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production. of seed potatoes is located. However, the number to vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukto. on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. I) The traps 'Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows: I. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macrosiphoniella sanborni (Gillette) Out of a total of 12,797 aphids, 5,187$(48\%)$ vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macro-siphoniella sanborni. of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763); however, EI. SI. WI and NI. where the distanecs from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (347). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector. Myzus persicae, are shown in Fig.3. The distribution pattern is typical except $S-2\;and\;W_3$, where several farmer's houses were found. If only the rice paddies were found in these locations. the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions: 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However. depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus. under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.297-304
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• 2004

The development of Aphidoletes aphidimyza, an aphidophagous gall midge, was studied at various constant temperatures ranging from 15 to $35^{\circ}C$, with $65{\pm}5\%$ RH, and a photo-period of 16L:8D. When A. aphidimyra was fed either on Aphis gossypii or Myzus persicae, it took 43.9 and 44.5 days, respectively, to develop from egg to pupa at $15^{\circ}C$, whereas at $25^{\circ}C$, 14.3 and 15.8 days. The developmental zero was 10.7 and $10.0^{\circ}C$, respectively, while the effective accumuative temperatures were 210.8 and 245.5 day-degrees. The nonlinear shape of temperature-dependent development, shown by A. aphidimyza when fed on either species of the aphids, was well described by the modified Sharpe and DeMichele model. When distribution model of completion time of development for each growth stage was expressed as physiological age and fitted to the Weibull fuction, the completion time of development gradually shortened from egg to larva, and to pupa. In addition, the coefficient of determination $r^2$ ranged between 0.86-0.93 and 0.85-0.94, respectively providing a good approximation of cumulative developmental rates. The life span of adult was 8.7 and 9.2 days at $15^{\circ}C$, and 3.1 and 2.7 days at $30^{\circ}C$, respectively. Egg incubation period was relatively short at $35^{\circ}C$ but hatchability was less than $50\%$ and the mortality of the larva at $35^{\circ}C$ reached $100\%$. At $30^{\circ}C$, the time of development lengthened and the adult longevity was short suggesting ill effect of high temperatures. Even though the life span of adults at $15^{\circ}C$ was relatively long, none moved freely in the rearing cage and no oviposition occurred. Accordingly, in case A. aphidimyza is adopted to suppress phytophagus aphid populations, it could be applicable to cropping systems with ambient temperatures above $20^{\circ}C$ and below $30^{\circ}C$. Within this range, A. aphidimyza adults was observed to be active and oviposit fully.

• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.116-127
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• 2021

In this study, insect pest communities and major insect pest species were investigated and compared among 30 cultivars of Hibiscus syriacus. Insects on H. syriacus were observed with the naked eye over 3 years (from 2018 to 2020) in Busan and Suwon. Except for Aphis gossypii (79,059 and 23,654 individuals in Busan and Suwon, respectively), 20 species (1,147 individuals) and 31 species (2,240 individuals) were found in Busan and Suwon, respectively. The number of insect pest species and individuals did not differ among H. syriacus cultivars, but there were differences according to study locations. The dominant insect pest species were A. gossypii, Rehimena surusalis, Rusicada privata, Halyomorpha halys, Haritalodes derogata, Dolycoris baccarum, and Plautia stali; the number of individuals in dominant species differed according to study location and year but not among H. syriacus cultivars. In summary, insect pest communities did not differ among 30 H. syriacus cultivars, but the matrix of surrounding environments where H. syriacus are planted may be more important.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.28-36
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• 1984

The relationship between ratio of virus diseases and the population of aphid vectors was studied by planting radishes(Rophanus sativus L. var. Chungsu gungjung) every 10 days and collecting aphids from April to November at Jeonju, Korea in 1982. Alate aphids were collected with yellow pan traps and virus infection ratios were checked with symptoms. The populations of flying aphids showed two peaks, one in the late May and one in the middle October in Jeonju and the population of aphid vectors also showed the same inclination. Of aphid vectors, Myzus persicae, Lipaphis erysimi, Brevicoryne brassicae, and Aphisgossypii were trapped and their percentages to total trapped aphids were $62.82\%(39,260/62,499)$ M. persicae was the most prevalent species and its percentages to aphid vectors were $82.53\%(32,401/39,260)$. High and sudden increase in virus infection ratio was found in spring while the trend in autumn was slow and low. A correlation coefficient between the population of virus vector aphid and virus infection ratio was $r=0.7414^*(\hat{Y}=8.1444+0.0551X)$ in spring and $r=0.9117^{**}(\hat{Y}=10.2590+0.463X)$ in autumn. The symptoms of radish virus diseases appeared approximately 15 days after virus vector aphids had attacked. Virus infection ratios were higher on plots where virus infected plants were reserved than on plots where they were removed.

• Korean Journal of Organic Agriculture
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• v.17 no.2
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• pp.227-236
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• 2009

This research was carried out to investigate the seasonal occurrence of major pests and the effects of releases of natural enemies for biological control of the major pests in eggplant greenhouse. A total of 8 pest species in 7 families were identified. Among these pests, Myzus persicae, Aphis gossypii, Frankliniella occidentalis, Tetranychus urticae and Trialeurodes vaporariorum were the dominant species in eggplant greenhouse. Two aphid species occurred mainly from May to June, but their populations decreased rapidly from July. The population density of F. occidentalis was high from June to July and T. urticae and T. vaporariorum were abundant from July to September during the growing season of eggplant. In the trials of biological control of pests, aphids could be suppressed within the range of $87{\sim}97%$ by two times releases of Chrysopa pallens eggs. F. occidentalis and T. urticae could be suppressed within the range of $76{\sim}90\;and\;87{\sim}91%$ by three times releases of Orius sauteri adults, respectively. The releases of C. pallens eggs and O. sauteri adults were as effective as three times applications of insecticides for the control of aphids, F occidentalis and T. urticae from May to September.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.245-250
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• 2000

These studies were conducted to investigate the effect of temperature on the development and seasonal occurrence of Chrysopa pallens Ramber, a predator of aphids. Mean developmental periods of C. pallens from egg to adult emergence at four different temperatures of 17, 22, 27, and $30^{\circ}C$ were 39.5, 32.0,25.0, and 19.8 days, respectively. The longevities of adult females of C. pallens at the four temperatures were 84.7, 79.6, 77.7, and 69.8 days, respectively, whereas the total numbers of eggs laid by a female were 973, 1085, 1637, and 1735, respectively. Egg hatchability, rate of adult emergence, and sex ratio of C. pallets were slighty higher with increased temperature with 84.1~95.9%, 67.6~86.3%, and 1:1. Under three humidity conditions of 35, 55 and 75% RH, the mean developmental periods of C. pallets from egg to adult emergence at the $27^{\circ}C$ were 26, 24, and 22.9 days, respectively, while the number of eggs laid by a female were 1042.8, 1526.5, and 1640.0, respectively. Oviposition of C. pallets usually began 5~6 days after the emergence at $27^{\circ}C$. Then females laid ca. 30~40 eggs a day, reaching a peak of 80~90 eggs a day about 22~28 days after the emergence. Population fluctuation of M. persicae and A. gossypii showed the highest peak in late May through the mid-June, and the second peak appeared in early~mid-September. The adult occurrence of C. pallens by the light trap record started from mid-May, and show two peaks, in mid-late July and mid-late September in Chonbuk area.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.421-429
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• 2012

The developmental time period of Aphis gossypii was studied in laboratory (six constant temperatures from 15 to $30^{\circ}C$ with 50~60% RH, and a photoperiod of 14L:10D) and in a cucumber plastic house. The mortality of A. gossypii in the laboratory was high in the 2nd (20.0%) and 3rd stage(13.3%) at low temperature but high in the 3rd (26.7%) and 4th stage (33.3%) at high temperatures. Mortality in the plastic house was high in the 1st and 2nd stage but there was no mortality in the 4th stage at low temperature. The total developmental period was longest at $15^{\circ}C$ (12.2 days) in the laboratory and shortest at $28.5^{\circ}C$ (4.09 days) in the plastic house. The lower threshold temperature at the total nymphal stage was $6.8^{\circ}C$ in laboratory. The thermal constant required to reach the total nymphal stage was 111.1DD. The relationship between the developmental rate and temperature fit the nonlinear model of Logan-6 which has the lowest value for the Akaike information criterion(AIC) and Bayesian information criterion(BIC). The distribution of completion of each development stage was well described by the 3-parameter Weibull function ($r^2=0.89{\sim}0.96$). This model accurately described the predicted and observed outcomes. Thus it is considered that the model can be used for predicting the optimal spray time for Aphis gossypii.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.85-88
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• 1979

The cotton aphid, Aphis gossypii Glover, is known as the most important vectant vector of citrus tristeza virus, cucumber mosaic virus, potato virus Y and potato leafroll virus. This study conducted to investigate the life history of cotton aphid at Suweon, Korea$(Lat.37^{\circ}16'N,\;Long\;126^{\circ}59'E)$. The aphids were reared in small cages placed over twig of hibiscus and on the leaves of cucumber. The results obtained were summarized as follows: 1. Overwintering eggs hatched from mid to late April, with a hatching rate averaging seventy-nine percent. 2. The early-born progeny have 22 generations and the late-born progeny have 6 generations on hibiscus and cucumber from April to October. 3. The fundatrigeniae leave tile the primary host in late May to early June and migrate to the secondary hosts. 4. From early to mid Oct., the gynoparae migrate from the secondary hosts to the primary host. 5. The average length of life was about 29 days and they produced an average of 70 nymphs each. 6. The maximum number of aphids produced per female was 117 in the spring. 7. The developmental period ranged from 6 to 16 days (average 8 days), the reproductive period from 12.2 to 24.6 days (average 19 days). 8. The average number of nymphs produced by a female per dys was about 3.7, with a maximum number of 17.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.35-41
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• 2003

Anthocorid bugs (Orius spp.) are known as polyphagous predators preying on thrips, aphids, mites, eggs of small insects and whiteflies. This study was conducted to investigate the nym-phal development, survival rate, longevity of Orius sauteri adult and oviposition, when nymphs of western flower thrips (Frankliniella occidentalis) and cotton aphid (Aphis gossypii), and eggs of two-spotted spider mite (Tetranychus uritcae) were fed as diets. Nymphal development of female/male O. sauferi fed with F. occidentalis, A. gossypii and T urticae took 12.2/12.8, 13.0/l3.2, and 17.9/17.8 days at 27$^{\circ}C$, respectively, Survival rates during nymphal development were 96.4, 78.4, 73.8%, longevity of female/male adults were 55.9/51.0, 30.2/30.8, and 25.8/25.1 days, and daily oviposition were 5.6, 4.1, and 1.9 eggs, respectively. Oviposition of O. sauteri fed with F. occidentalis usually began 3-4 days after emergence at 27$^{\circ}C$, and reached at its peak of 7-8 eggs female day 20-40 days after emergence.

• Korean journal of applied entomology
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• v.55 no.1
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• pp.45-51
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• 2016

Thirty-seven species of insect pests were surveyed on different area blueberry farms in Jeonbuk province during 2013~2014. Six principal insect pests were found, including Dasineura oxycoccana Johnson, Aphis gossypii Glover, Scirtothrips dorsalis Hood, Ricania sp., Hyphantria cunea Drury, and Latoia consocia Walker. A. gossypii infestation was severe at Iksan and Jinan in middle May. S. dorsalis infestation was severe at all surveyed area in early June, which is the flowering season, and the degree of damage caused was higher in young plants. Ricania sp. was abundant in Jinan and Sunchang, and then appeared to spread across all areas in Jeonbuk. H. cunea had a tendency to concentrate in Iksan during June. Five species of Limacodidae was found, including L. consocia, which was dominant in all areas surveyed, with densities higher then those of the others four species. The degree of damage due to D. oxycoccana was higher in the plain areas (Iksan) than in the middle-mountain areas (Jinan, Sunchang). The rate of damage was 60~78% higher in young plant stages (i.e., those under 3 years of tree age) than in those over 5 years old (30~50%). Moreover, the rate of damage observed in greenhouses was 50~80% higher than that observed in the field (30~40%).