• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.99-105
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• 1986

The green peach aphids(Myzus persicae) collected in a field had been successively selected by acephate(O, S-dimethyl N-acetyl phosphoroamidothioate) in the laboratory. The selected aphid strain in the 20th generation demonstrated relatively high resistance to acephate as well as relatively high cross-resistance to cypermethrin and oxydemeton-methyl, except pirimicarb. The different esterase isozymes with the strains were detected by the agarose gel electrophoresis and among the isozymes the band of ${\beta}-2$ was only specific for the acephate resistant strains.

• The Korean Journal of Mycology
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• v.34 no.2
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• pp.112-118
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• 2006

To select efficient entomopathogenic fungal strains of Lecanicillium for the biocontrol of aphid, Myzus persicae, conidial suspension ($1{\times}10\;conidia/ml$) was sprayed onto a detached Chinese cabbage leaf in a petri dish with a dampened filter paper that had 20 nymphs of aphid. Lecancillium strain 4078 and 6543 were the best strains for the biocontrol of aphid at high temperature of $30^{\circ}C$ and low relative humidity (RH) of 85%, respectively. The cumulative mortality of strain 4078 at $30^{\circ}C$ after 3 days was 100% and that of strain 6543 was 90% at 85% RH after 5 days. Strain 4078 also exhibited almost 100% germination ratio of conidia and high rate of mycelial growth at the broad temperature-range of $15{\sim}25^{\circ}C$. The strain 4078 and 6543 were all identified as Lecanicillium species based on the DNA sequences (accession no.: EF026004 and EF026005, respectively) of the ITS regions of the fungi. Excellent production of aerial conidia of strain 6543 was accomplished by using steamed polished rice as the solid culture medium.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.191-195
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• 1981

Cucurbits including pumpkin (Cucurbita pepo), gourd (Lagenariaa siceraria), cucumber (Cucumis sativus), melon(Cucumis melo) and watermelon(Cucurbita anguria) were diseased with mosaic symptoms. The causal virus was identified as watermelon mosaic virus(WMV). The WMV was transmitted by Myzus persicae Sulzer, and no seed borne virus was found. The virus caused large local lesions on the inoculated leaves of the Chenopodium amaranticolor and mosaic symptom on the upper leaves of Cucumis melo, Cucumis sativus, Lagenaria siceraria, Cucurbita anguria and Cucurbita pepo. There were no symptoms on the inoculated leaves of the Nicotiana tabacum var. Bright yellow, Nicotiana glutinosa, Vigna unguiculata. Petunia hybrida and Datura stramonium. Thermal inactivation point was $55\~65^{\circ}C$, dilution end point was $10^{-4}\;10^{-5}$ and longevity in vitro of the virus was $7\~8$ days. The virus showed positive reaction against watermelon mosaic virus antiserum in microprecipitin tests. The virus particles were flexuous rods in size of 750 nm.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.348-353
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• 1993

The fluctuation of insecticide resistance in the green peach aphid (GPA) in fields was investigated by caboxy1 esterase (CE) activity index analysis. Of the GP A Populations occurred on the red pepper seedlings, aphids in the untreaLed and treaLed with acephate plots showed 40 and 78 resistance percent (RP), respectively. Aphids in the untreated kale field showed the RP value 24 in July, contrast to 83 in October. Mean RPs of aphids from 18 localities were 50 + 14 in summer and B2+ 10 in late fall, indicating a seasonal fluctuation of Lhe CE activity.

• 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 Organic Agriculture
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• v.24 no.4
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• pp.849-857
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• 2016

In the growth of the Rubus coreanus Miquel fruits, the unripened (10 days) and ripened (25 days) fruits after flowering were harvested. The chemical characteristics of different maturational stages of the unripened and ripened fruits were investigated. Total amount of phenolic compounds was 4.00-7.56% in the unripened fruits and 3.78-5.57% in the ripened fruits, respectively. Furthermore, total amounts of organic acids such as malic, citric, succinic, and oxalic acids were 16.40 mg/100 g in the unripened fruits and 28.82 mg/100 g in the ripened fruits, respectively. In organic acids of the unripened and the ripened fruits, citric acid (8.76-15.47 mg/100 g) was the highest amount among other organic acids. Soluble sugars were significantly increased from 11.07 to 21.54% in the unripened and ripened fruits. Therefore, ripened fruits had the high levels of phenolic compounds, organic acids and soluble sugars. For the biological studies of R. coreanus, methanol extracts of R. coreanus leaves, fruits, and stems were evaluated for their insecticidal activities against Myzus persicae (Hemiptera: Aphididae), Plutella xylostella (Lepioptera: Plutellidae) and Spodoptera litura (Lepioptera: Noctuidae) by leaf dipping method. From these results, the extract of R. coreanus leaves revealed potent insecticidal activity against P. xylostella. However, the methanol extracts of R. coreanus fruits and stems had no any insecticidal activity against M. persicae, P. xylostella and S. litura. The R. coreanus leaves have promising potential as new insecticidal agent against P. xylostella.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.261-269
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• 1987

A virus which induced yellowing, vein banding and ruffling on pepper in the field was investigated. The virus reacted strongly with PVY - antiserum in ELISA, but not with antisera of cucumber mosaic virus, tobacco mosaic virus, tomato black ring virus, alfalfa mosaic virus, tomato spotted wilt virus, tobacco etch virus, pepper mottle virus, and tobacco ringspot virus. Electron micrographs revealed that the virus was a flexuous rod of 750-760nm in length. The virus was transmitted mechanically and by Myzus persicae in a nonpersistent manner. The host range was similar to that of PVY, except that Chenopodium amaranticolor and C. quinoa were infected systemiclly.

• Korean journal of applied entomology
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• v.17 no.3 s.36
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• pp.131-138
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• 1978

A virus named Cymbidium mild mosaic virus(Cy MMV), was mechanically transmitted to Chenopodium amaranticolor from the leaves of Cymbidium with mild mosaic symptoms. The virus was cultured in C. amaranticolor, in which it produced local chlorotic and ring spots, followed by systemic vein clearing with distortion. CyMMV infected 7 out of 35 species of plants. In C. amaranticolor juice infectivity was lost by heating at $90^{\circ}C$ for 10 miuntes, and by aging at$20^{\circ}C$ for 60 days, and by diluting at $10^{-6}$ when bioassayed on C. amaranticolor. CyMMV was not transmitted by Myzus persicae. The virus was purified after clarification of homogenized C. amaranticolor leaf tissues with chloroform, by differential centrifugation followed by sucrose density gradient centrifugation. Electron microscopic examination of purified preparation showed spherical particles of 28nm in diameter. The UV absorption spectrum of purified preparation was typical of u nucleoprotein (max. at 261nm. min. at 243nm), and showed 260/280=1.72 and max/min=1.26. The value of the sedimentation coefficient of the virus was S20.w=126. In gel-diffusion tests, CyMMV antiserum reacted with CarMV, but not with any of four other viruses (BBWV, CRSV, CMV, TBRV) having similar particles and properties in vitro. In ultra-thin sections of CyMMV infected tissues, a large number of virus particles were found in the cytoplasm of mesophyll cells and in xylem vessels.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.113-121
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• 1994

The green peach aphid was relatively the majority(36.9-72.3% ) among all alate aphids collected from tobacco plants. Density of glatae was relatively lower on varieties Tl 1112 and Br 21 than on Va 115 or Y S A among seven varieties tested. However, no considerable difference was observed in general biology of nymphs produced by alatae on the tobacco varieties. About 55% of alate green peach aphid collected from tobacco fields produced progency, and over 80% of the nymphs became adults on cut tobacco leaves in petri dish. Adult longevity of both alate and apteral green peach aphid was shorter, and numbers of nymphs produced by both types were lower in summer than in autumn. Apterae produced more nymphs than alatae, but the longevity of apterae was shorter.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.149-156
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• 2014

The resistance levels of the green peach aphid, Myzus persicae (Sulzer), against 10 insecticides was checked and selected the applicable insecticide resistance markers. We conducted our study in 5 cabbage cultivation regions (Pyeongchang, Hongcheon, Bongwha, Muju, and Jeju) of Korea, over 3 successive years (2009-2011). We selected a multi-resistant (MR) strain from among the 5 field-collected populations. We analyzed esterase over-expression and mutation(s) in the target sites, by using native isoelectric focusing (IEF) and quantitative sequencing (QS). We detected esterase over-expression and StoF mutation in the acetylcholinesterase 1 gene (ace1) in all of the field-collected populations, including the MR strain. We did not detect the LtoF mutation, which is a well-known knockdown resistance (kdr) mutation in the para-type sodium channel gene (para), in the MR strain; however, the value of the MR strain for bifenthrin was 3,461-fold higher than that of the susceptible strain. Our results indicate that insecticide resistance is more effectively evaluated using molecular markers than by conducting a bioassay. The molecular markers StoF in ace1 and MtoL in para can easily be applied in diagnostic methods such as QS or PCR amplification of specific alleles (PASA). These methods may be extended to management of M. persicae resistance in the field.