• Korean journal of applied entomology
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• v.25 no.3 s.68
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• pp.129-132
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• 1986

Colonizing aphid species on Chinese cabbage, radish, red pepper and cucumber and their seasonal fluctuations were investigated without insecticide treatment during $1982{\sim}1984$ at an experimental farm in Suweon. The major species among the colonizing aphids in each crops were Myzus persicae (Sulzer) and Lipaphis erysimi (Kaltenbach) on Chinese cabbage and radish; M. persicae (Sulzer) and Aphis gossipii Glaver on red pepper; and A. gossipii Glover on cucumber, respectively. Over 200mm of rainfalls within a 10-day period reduced the aphid populations drastically. Relative abundance of the two major aphids on Chinese cabbage and radish, and on red pepper showed inverse relationships between the spring and autumn densities within the same year.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.269-274
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• 2006

Temperature-dependent development studies of two aphid species, A. egomae and A. gossypii occurring in green perilla greenhouse were conducted at $15{\sim}35^{\circ}C$, and 16:8 (L:D h) of light period in the laboratory. The mortality of two aphid species was high in young stages (1st and 2nd). In A. egomae, the mortalitiy increased with increasing and decreasing temperature: the mortalitie at $15^{\circ}C$ and $35^{\circ}C$ were 22.3% and 15.6%, respectively. While the mortalities of A. gossypii increased with increasing temperature: the mortality at $35^{\circ}C$ was 50.0%. The developmental periods of A. egomae and A. gossypii ranged from 20.8days to 5.4days and from 22.6days to 9.1days at $15^{\circ}C$ to $30^{\circ}C$ of temperature resion, respectively, and were 7.2days and 10.7days at $35^{\circ}C$ for each species. The lower developmental threshold temperatures for total nymphs of A. egoame and A. gossypii were $9.9^{\circ}C$ and $4.9^{\circ}C$, respectively and an effective degree-days (DD) for the developmental completion of total nymph were 108.0 DD for.A. egomae and 221.2DD for A. gossypii. In green perilla greenhouse, the occurrence period of A. gossypii was earlier about 15 days than that of A. egomae. When the occurrence period of two aphid species was estimated by degree-days based on lower threshold temperatures, A. gossypii occurred earlier than A. egomae in the field. A. gossypii occurred from early April and showed dominant position to late May compared with A. egomae Whereas, A egomae started to occur from mid April and then were abundant after late May followed by abrupt population crash around late July.

• 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.51 no.4
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• pp.397-403
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• 2012

This study compared the Aphelinus varipes and Aphelinus asychis in terms of how they parasitized the cotton aphid, Aphis gossypii and green peach aphid, Myzus persicae. Host-feeding, parasitism, emergence, the proportion of females and development time were all studied at 15, 20, 25 and $30^{\circ}C$ in controlled climate cabinets. When A. gossypii were provided for the two aphid parasitoids, the number of aphids killed by host-feeding for A. varipes (5.4 and 9.7 aphids) at $15^{\circ}C$ and $25^{\circ}C$ was higher than those for A. asychis (2.0 and 2.9 aphids). At $15^{\circ}C$ and $30^{\circ}C$, the parasitized A. gossypii were higher in A. varipes (11.1 and 21 aphids) than in A. asychis (7 and 12.3 aphids). The emergence rate was also significantly different between A. varipes (83.3%) and A. asychis (69.4%). The proportion of females was higher for A. asychis (75.2 and 73.9%) than for A. varipes (19.5 and 48.6%) at $15^{\circ}C$ and $30^{\circ}C$, respectively. No significant differences were found in development time between the two parasitoids. When M. persicae were provided for the two parasitoid species, the host-feeding number and the emergence rate of two parasitoids were not different at all four temperatures. The M. persicae were more highly parasitized by A. varipes (12.1 and 17.1 aphids) than by A. asychis (6.1, 10 aphids) at 20 and $25^{\circ}C$. The proportion of females for A. varipes (65.3 and 90.0%) was higher than that for A. asychis (34.4 and 78.8%) at $15^{\circ}C$ and $25^{\circ}C$. The development time from oviposition to the adult emergence of A. varipes (19.9 d) was significantly longer than that of A. asychis (16.5 d) at $20^{\circ}C$. Development times decreased with increasing temperature for both in two parasitoid species.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.247-255
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• 2015

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) infests citrus orchards, causing sooty mold damage to the fruits. This study was conducted to investigate the colonizing route of A. gossypii in citrus orchards in a non-heating plastic-film house during the early season. The overwintering eggs of the aphids are frequently found on summer shoots of the citrus trees. The eggs were mostly those of Aphis citricola, without any A. gossypii when hatched. The colonization of citrus trees by alate A. gossypii in non-heating plastic-film houses was mainly observed twice, with advanced flight in late April and delayed flight in late May. The delayed flight was synchronized with the timing of the emergence of alate A. gossypii from the fundatrix generation in the holocyclic life cycle. During advanced flight in closed citrus orchards, alate A. gossypii were caught in yellow water traps installed in the fields, and the populations were found to originate from the surviving populations of the anholocyclic life cycle. Consequently, we concluded that citrus tree colonization with A. gossypii occurred during the advanced flight of the anholocyclic and the delayed flight of the holocyclic life cycle.

• Korean journal of applied entomology
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• v.50 no.1
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• pp.79-82
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• 2011

Biological control of Aphis gossypii by natural enemies was carried out in watermelon from April to June. Aphidius colemani was released 3 times at rate of $2/m^2$ to control A. gossypii(April 24, May 8, and May 22 in 2007). In A. colemani-released plots, A. gossypii showed low population density of < 0.6 per leaf with the highest parasitism of 57.2%, and 2.0~10.6% in the percentage of leaves with aphids. In control, the population of A. gossypii kept on increasing from early May and reached 653.2/leaf on may 29.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.113-124
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• 2017

Cotton aphid (Aphis gossypii) and green peach aphid (Myzus persicae) are serious pests damaging various crops including vegetables such as pepper, cucumber, and Chinese cabbage. We conducted a study to control two aphids with secondary metabolite of entomopathogenic fungus Beauveria bassiana. A B. bassiana was already selected as a high virulence isolate against cotton aphid and green peach aphid. The culture filtrate of the isolate showed high pathogenicity against both aphids as 100% mortality against cotton aphid 3 days after treatment and 99% against green peach aphid 5 days after treatment. A different fraction extracts with $CHCl_3$ : MeOH of B. bassiana culture filtrate (30:1, 50:1, 70:1, 90:1, 100:1; v/v) through silica gel column chromatography showed different control effect to aphids. Among them, 50:1 ($CHCl_3$ : MeOH) fraction had highest mortality as 77.3% and 75.4% against A. gossypii and M. persicae, respectively. A mixture of each fraction (1:1) had no synergistic effects because control effect of every mixture was lower than only 50:1 extract; for example, mortality of 50:1 + 70:1 showed $2^{nd}$ highest as 72% of cotton aphid and 70.2% of green peach aphid and other mixtures were lower than these values. In future we will study the identification and mass production of aphicidal compound isolated from 50:1 fraction to develop stable aphid control agent.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.16-20
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• 2004

Aphis gossypii Glover(Homoptera: Aphididae) is an serious pest on various crops. This experiment was conducted to evaluate the effect of A. gossypii Glover on the growth of oriental melon and the plant recovery after removing A. gossypii. Visible damage symptom caused by A. gossypii feeding to oriental melon was leaf distortion and stunting. A. gossypii feeding for 20 days on oriental melon significantly reduced the growth of oriental melon with increasing A. gossypii density level. Plant growth was decreased by 63${\sim}$69%, 62${\sim}$88% and 49${\sim}$70% in plant height, leaf area and dry weight, respectively. During 10 day after aphids removal, the infested leaves remained stunt, however, new shoot and leaf recovered gradually. By 20 day, plant height, leaf area and dry weight substantially increased in 5 aphid per plant. Plant recovered rapidly with day and among aphid density level, 5 aphid per plant showed rapid recovery. When plant were infested with several density of aphid per plant, sugar contents of total leaves were not significantly different between aphid density level. Whereas, sugar contents of lear infested with aphid per leaf were decreased with increasing cumulative aphid-days.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.345-352
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• 2008

The seasonal occurrence of insect pests in watermelon cultivated in greenhouses was surveyed in Gochang from 2006 to 2007 considering three seasonal types of culture: forcing culture, semi-forcing culture and retarding culture. Aphis gossypii, mites (Tetranychus urticae+T. kanzawai) and Palpita indica were the most serious pest species in watermelon greenhouse culture. A. gossypii and mites showed high density during the months of June and September in semi-forcing and retarding culture, respectively. Palpita indica was observed only in retarding culture. Leaf damage by Palpita indica was observed from the middle of August and peaked to 79.4% damage in the middle of September. Thrips and whiteflies were captured in high density by the yellow sticky trap in semi-forcing culture and retarding culture but these insects showed low population density in watermelon leaves.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.401-407
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• 2015

This study describes the development of a method for monitoring Aphis gossypii in greenhouse cucumber fields that was used during 2013 and 2014. The dispersion pattern of A. gossypii was determined by commonly used methods: Taylor's power law (TPL) and Iwao's patchiness regression (IPR). The sample unit was determined by linear regression analysis between mean density of sample unit versus whole plant. The optimum sample unit for different plant growth stages was two leaves (median and the lowest + 1 leaf) when the total number of leaves was less than nine, and three leaves (4th, 7th from canopy, and the lowest +1 leaf) when the total number of leaves was greater than nine. A. gossypii showed an aggregated distribution pattern, as the slopes of both TPL and IPR lines were greater than 1. TPL provided a better description of the mean-variance relationship than did IPR. The slopes and intercepts of TPL and IPR from leaf samples did not differ between the surveyed years. Fixed precision levels (D) for a sequential sampling plan were developed using Green's and Kuno's equations based on the number of aphid in a leaf sample. Green's method was more efficient than Kuno's to stop sampling. The number of samples needed to estimate the density of A. gossypii increased at higher D levels and lower mean densities. The cumulative number of aphids needed to stop sampling increased at higher D levels and with fewer plants sampled. Thus to estimate 10 aphids per leaf, 13 plants needed to be sampled, and the cumulative number of aphids to stop sampling was 131.