• Korean journal of applied entomology
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• v.21 no.2 s.51
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• pp.53-60
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• 1982

Isolates of soybean mosaic virus (SMV) strains classified based on virulence in silt resistant soybean cultivars caused the same reactions in soybean cultivars used as differentials as those obtained by sap inoculations to the same cultivars. Five species of aphids (Myzus persicae SULZ., Aphis craccivora KOCH, Aphis citricola VAN., Rhopalosiphum maidis FIT., End R. padi L.) were able to transmit each of SMV strains. However, R. maidis and R. padi were inefficient vectors for transmission of SMV strain G3. Spread if four SMV strains (G2, G3, G6, and G7) was monitored in the field from sapinoculated plants in a one meter row of Williams soybeans (source plants) to plants in an adjacent row of Williams 80cm away (test plants). Test plants wert downwind from the source plants. A complete block design was used. Spread of strain G6 was significantly greater than that of other three strains. Two hundred six aphids were collected from June 27, 1979 to August 2, 1979 in the same field. A. citricola was the mist prevalent, comprising $68\%$ of the total aphids. Yields of Williams inoculated with each strain were also compared. Yields were the least from plants inoculated with strain G2 following G6, G3, and G7 in that order.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.267-274
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• 2000

As the pest of the citrus in Cheju, 69 insect species and 5 animal species were investigated during 1996 to 1998. Of these, Panonychus citri, Phyllocnistis citrella, Aphis citricola, Aphis gossypii and Frankliniella occidentalis are major pests. Especially, F. occidentalis and Peridroma saucia are very important species because of increasing damage. The number of pests species injuring leaf, branch, fruit and flower of the citrus are 36, 16, 41 and 2 species respectively. The rate of damaged fruits by pests is 20.5% in 1997 and 18.6% in 1998 and the rate of bad quality fruits is 6.4% and 6.7% respectively.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.259-264
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• 1993

The experiment was carried out to investigate Insecticide susceptibility of the spiraea aphid (Aphis citricola) in apple orchards In Korea, using dipping method. Although insecticIde susceptibility vaned with local and seasonal populations, the susceptibility to demeLon S-rnethyl and phosphamidons was different from that Lo the other insecticides. The LCso values were 10 ppm for deltamethrin and chloropyrifos, 103 ~ 629 ppm for demeton S-methy1, acephate, phosphamidon, monocrotophos and vamldothion, 12,200 ppm for EPN, and 1,745 ppm for pirimicarb. 'When Insecticide susceptibility was compared between the S-clone selected from a population on the host plant spiraea and the R-clone selected from a population on the apple tree, the resistance ratio as expressed by RIS ratio of $LC_{50}$ was 78 for phosphamidon and 546 for pirimicarb. Esterase zymogram determined by the agar gel electrophoresIs revealed a significant difference between the clones. The activity of the E2, E5, E6 and E7 of the R-clone was higher than that of the S-clone, It is suggesLed that the Increased esterase activity may be involved in the mechanism of insecticide resistance in the spiraea aphid, although the involvement of other factor(s) may not be ruled out.

• Korean journal of applied entomology
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• v.25 no.4 s.69
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• pp.209-213
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• 1986

Dominant aphid species and seasonal fluctuations of the colonizing aphids on apple tree, peach tree, and pear tree were examined without insecticide treatment during $1982{\sim}1984$ in Suweon. The dominant species among the colonizing aphids in each fruit tree were Myzus malisuctus in April-June and Aphis citricola in Aug.-Oct. on apple tree; Myzus persicae in early springtime and Hyalopterus pruni in May-Oct. on peach tree; Sappaphis piri in April-June, Oct. and Aphis citricola in July-Sept. on pear tree. M. malisuctus and A. citricola on apple tree showed 3 peaks a year; the former was early June, late Aug. and early Oct., the latter early June, middle Aug. and late Sept. M. persicae on peach tree showed peak on late May to early June, and H. pruni on middle June and middle Oct. S. piri and A. citricola on pear tree showed 2 peaks a year; the former was late May and late Oct., the latter early June and early Sept.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.89-94
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• 1995

Resistance mechanism of organophosphorus insecticides (OPs) in the spiraea aphid, whose populations were originated from several apple orchards where various OPs were frequently sprayed, was investigated. For Wonju population to which insecticides were not sprayed, resistance ratios (BRs) for pirimicarb, phosphamidon, and demeton S-methyl re 49, 31, and 5, respectively. However, for Yesan population to which OPs were sprayed 5 times, RRs for pirimicarb, phosphamidn, and dementon were 830, 536, and 204, respectively. The esterase activities of Wonju and Yesean populations increased by 44.5 and 92.0% compare to that of Kwagju population. R/S a values (S clone Kwangju population; R clone: Iechon opulation) for acetylcholinesterase (AChE) inhibition (${I}_{50}$) by pirimicarb and phosphamidon were 299.2 and 186.0, respectively. Our results indicate that increase of esterase activity and reduction of AChE sensitivity seemed to contribute insecticide resistance of the spiraea aphid.

• 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.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.55-60
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• 2001

The efficacy of petroleum spray oil (PSO; D-C Tron $Plus^{(R)}$) against spirea aphid (Aphis citricola) and two scales (lcerya purchasi and Planococcus cryptus) on citrus was tested in Jeju, Korea. The control value of 0.33% PSO against spirea aphid was over 90% at 3 and 6 days after treatment (DAT), and then decreased to about 80% at 9 and 14 DAT. Spraying of PSO (0.33, 0.66, 1%) against cottony-cushion scale showed a much lower control value (less than 50%) during the investigation period compared to that of the conventional pesticide (Methion). When used against tile scale, Planococcus cryptus, the control value of 1% PSO was 95%, but that of 0.33% and 0.66% PSO only ranged from 50 to 80%, lower than the conventional pesticide. The results of this study, as with a previous study, suggest that spraying of 0.33% and 0.5% PSO not only controls the spirea aphid, but also reduces the density of two scales (lcerya purchasi and Planococcus cryptus) on citrus tree in Jeju, without phytotoxic damage.