The exotic aphid pest, pomegranate aphid, Aphis punicae Parsserini, 1863 (Hemiptera: Aphididae), is newly recognized in the Korean peninsula. This species is originally distributed throughout the Mediterranean regions, the Middle East, Ethiopia, India, Pakistan, Indonesia, and Turkey. In the major producers of pomegranate such as India and the Mediterranean regions, this species is regarded as one of the most serious insect pests inflicting injury on pomegranate, Punica granatum Linnaeus. By sucking plant sap and excreting honeydew, aphids cause various plant diseases and virus infections which are more likely to occur as population size increases. Aphis punicae infests together commonly with Aphis gosspii Glover, and rarely with Aphis craccivora Koch and Aphis spiraecola Patch on P. granatum in Korea. In this study, we first compared two closely related species, A. gossypii and A. punicae, based on morphometric analysis to confirm their morphological relationships. Second molecular identification using mitochondrial COI barcode region was performed for the aphid samples collected from P. granatum.

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the major insect pests of cucumber, Cucumis sativus L. The spatial distribution and occurrence of Aphis gossypii Glover on greenhouse cucumber, Cucumis sativus L., were studied to provide an efficient and reliable sampling plan for its control. A highly clumped pattern was observed among plants (TPL b = 1.63) within a greenhouse. To develop a sampling plan for visual enumeration, leaves within plants were selected by different percentages of leaves (eg., 3rd and 6th, 6th and 9th leaf,…from the bottom of the plant) and then compared the accuracies and efficiencies by relative net precision (RNP). The results indicated that selecting leaves from the bottom of the plant by systemic sampling methods were relatively high as other sampling methods.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pests in various vegetable crops. In Korea, some field populations of A. gossypii especially in greenhouse showed high resistance against neonicotinoids. The imidaclopridresistant strain (IR) selected from one of the greenhouse strains was found to be about 3,800 folds more resistant to imidacloprid, compared to the susceptible strain (S), as judged by LC50 values. To identify differentially expressed genes in IR, an isogenic strain, reverse susceptible strain (IRS) was generated from IR and comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from both IR and IRS. Also we confirmed protein expression patterns by 2DE and detoxification enzyme over-expression by synergist test. However there was no significant variation among IR, IRS and S. Comparison of the nucleotide sequence of seven nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5,7 and beta 1) genes from S and IR strain revealed a point mutation causing an arginine to threonine substitution (R81T) in the loop D region of the nAChR beta 1 subunit of the IR. These mechanisms were also reported in M. persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids. Moreover an extra point mutation, L80S (leucine to serine substitution) was also detected nearby R81T mutation in nAChR beta 1 subunit variant. These mutations can be an additive factor in imidacloprid resistance in A. gossypii. This is the first report of imidacloprid resistance mechanism in A.gossypii. Further, this would be helpful in managing A. gossypii resistant populations in field.

In terms of aphid species identification, both host plant association and morphological characteristics are crucial factors. However, aphids in the genus Aphis Linnaeus (Hemiptera: Aphididae) often are cryptic in morphology due to their rapid radiation. Moreover, overlapping host plant species can make difficult situation worse. Three cryptic species Aphis gossypii Glover, Aphis glycines Matsumura, and Aphis rhamnicola sp. nov. occur together on the Buckthorn, Rhamnus spp. in the overwintering season in Korea. Due to lacking informative morphological characters and host plant sharing, the new species recently has been recognized as a distinct species. In this study, A. rhamnicola sp. nov. on various host plants was compared with the primary host sharing species, A. gossypii and A. glycines, based on morphological and molecular characteristics. In the results, there were significant genetic differences between three species, despite the high similarities in morphology. Our results provide strong evidence for establishing new species, which seems to be a typical heteroecious species that alternates between only primary host, Rhamnus spp., and various secondary hosts. We describe a new species, A. rhamnicola sp. nov., for apterous and alate vivipara, fundatrix, ovipara, and gynopara, including diagnostic key for host sharing species in genus Aphis.

목화진딧물 (Aphis gossypii)의 온도에 따른 발육시험을 실내 15, 18, 21, 24, 27, 30℃의 6개 항온, 광주기 14L:10D, 상대습도 50∼60% 조건과 오이 비닐하우스에서 3월 23일부터 8월 20일까지 6회 접종하여 수행하였다. 실내사망률은 저온에서는 2~3령충의 사망률이 높았고 온도가 증가할수록 3~4령충의 사망률이 높았으며 고온에서 전체 사망률이 높았다. 전체 약충의 발육기간은 실내에서 15℃에서 12.2일로 가장 짧았으며 변온의 28.5℃에서 4.09일로 가장 짧았다. 온도와 발육율과의 관계를 보기위해 선형 및 3개의 비선형 모형(Briere 1, Lactin 2, Logan 6)을 이용하여 분석한 결과, 선형모형을 이용하여 전체약충의 발육영점온도는 6.8℃였으며 발육유효적산온도는 각각 111.1DD였다. 3가지 비선형 모형중 Logan-6 모형이 전약충, 후약충 전체약충 단계에서 AIC와 BIC 값이 가장 적어 온도와 발육율과의 관계를 잘 설명하였으며, 발육단계별 발육완료분포는 3-parameter Weibull 함수를 사용하였으며 전약충, 후약충, 전체약충에서 r2 값이 0.88~0.91로 높은 값을 보여 양호한 모형 적합성을 보였으며 정식시기별 성충 발생 예측치와 포장 조사치가 일치하여 방제적기 추정에 유용하게 사용할 수 있을 것이다.

Insecticidal and repellent activity of sandalwood oil (Santalum austrocaledonium) and its components was tested against cotton aphid , Aphis gossypii in laboratory and field. The activity was estimated by calculating survival rate of aphid after application of sandalwood oil and its components. Analysis by gas chromatography-mass spectrometry led to identification of 5 compounds, alpha-santatol, bergamotol, epi-beta-santalol, and beta-satalol. The components of sandalwood oil was isolated by column chromatography for testing insecticidal and repellent activity. Santalol showed strong insecticidal and repellent activity as a commercial insecticide, imidachloprid. Sandalwood oil and isolated alpha-santatol and beta-santatol also showed strong insecticidal and repellent activity, however there was no significant difference among them.

The cotton aphid, Aphis gossypii (Glover) (Hemiptera:Aphididae), is a highly polyphagous pest that directly or indirectly damages cultivated plants. Six field-collected populations of cotton aphid, A. gossypii (BY-A, BY-B, YJ-A, YJ-B, CJ-A, and CJ-B) were tested for susceptibility to 14 different insecticides. Most population exhibited high to very high levels of resistance to neonicotinoid. Among them, a strain showing resistance to imidacloprid were selected and showed 1,543-fold in resistance as compared with susceptible strain. Piperonyl butoxide (PBO), diethyl maleate (DEM), and S,S,S tributyl-phosphorothiolate (DEF) failed to synergize imidacloprid in this resistant population. In addition, the activity of detoxification enzymes (P450, EST, GST) were no differences between susceptibility and imidalcoprid resistance strain. However, by analyzing the nicotinic acetylcholine receptor β1 subunit loop D, R81T point mutation was detected in BY-A, BY-B, YJ-A, and YJ-B strain.

The cotton aphid, Aphis gossypii Glover is an important sap-sucking pest of many pant, including cucumber and pepper. The objective of the present study was to determine the effects of sublethal concentrations of two insecticides (imidacloprid and flonicamid) and the action mechanisms on the feeding behavior of A. gossypii. The median lethal concentrations (LC50) of imidacloprid and flonicamid for adult A. gossypii were 2.01 and 1.92 ppm, respectively. The sublethal concentrations of imidacloprid were 0.22 ppm (LC10) and 0.82 ppm (LC30), and those of flonicamid were 0.094 ppm (LC10) and 0.56 ppm (LC30). The developmental period of A. gossypii nymphs at LC30 was 3.6 days for both insecticide which shorter than controls (4.2 days). Adult longevities at LC10 and LC30 of imidacloprid were 15.2 and 13.6 days, respectively. Adult longevity at LC10 and LC30 of flonicamid was 11.1 and 9.9 days, respectively. Control adult longevity was 15.5 days. Total fecundity was decreased at both sublethal concentration of two insecticides. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid and flonicamid had significant effects on the duration of phloem ingestion. However, higher doses of flonicamid induced starvation by inhibition of phloem ingestion and higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 300-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. A highly imidacloprid-resistant local field population (L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. To identify differentially expressed genes in IR or L, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from IR, L and S strains. Futhermore, to search the resistance associated proteins in IR or L, comparative proteome analyses based on 2DE were conducted using total proteins extracted from IR, L and S strains. Few common candidate genes detected among IR and L such as ABC genes. Comparison of the nucleotide sequence of six nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5, beta 1) genes from IR, L and S strain revealed a point mutation in the loop D region of the nAChR beta 1 subunit of the IR, causing an arginine to threonine substitution (R81T). These mechanisms also reported in Myzus persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids.

Many polyphagous herbivore insects considered as a single species are indeed comprised of genetically differentiated host related races that utilize several unrelated plant families. Aphis gossypii Glover, one of the extremely polyphagous aphid species, has more than 100 host plants distributed worldwide. In Korea, it takes holocyclic life cycle, with a number of primary hosts, which is unusual for other aphid species. However, former population genetic studies on A. gossypii have dealt with the populations from only a few agricultural host plants. In this study, we hypothesized that different primary host utilization may be restricted for certain host races and this may play a key role of the genetic differentiation in this species. We collected the cotten aphid populations from 36 different host plants, 5 primary and 31 secondary hosts including various wild and non-cultivated plants. To determine population genetic structure, we analyzed genetic differentiation among those populations using 9 microsatellite loci. As results, four genetically distinct clusters were verified. Of the five primary host populations, there were significant gaps in genetic differences between Rhamnus-associated group and Hibiscus-associated group, and the other populations were affinitive with the Hibiscus-associated group. Overall, primary host populations have a higher level of genetic diversity than secondary host populations. Several populations associated with secondary hosts such as spiderwort, madder, and Korean lettuce were considerably differentiated in the result of principle component analysis, which nearly showed the species level difference similar to Aphis glycines Matsumura and Aphis sp. ex Rhamnus. Thus, there could be reproductively isolated by the loss of primary hosts, and might be already speciated from A. gossypii

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in the cultivation of various vegetables. A highly imidacloprid-resistant field population (CA-L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. IEF and 2DE analyses revealed that general esterase isozyme (pI. 5) in CA-L were dramatically overexpressed and more isozyme spots identified in CA-L compared to susceptible (CA-S) strain. To identify differentially expressed genes in CA-L, comparative transcriptome analyses based on GS-FLX were conducted with total RNA extracted from CA-L, which generated ca. 143 Mb reads. Previously reported, comparative transcriptome analyses performed in imidacloprid resistant (CA-IR) and CA-S. The comparative transcriptome analyses re-investigated after all data sets were combined together. As previously reported, seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in CA-IR and L. These results suggested that ABCC subfamily associated with imidacloprid resistance in A. gossypii.

After pea aphid Acyrthosiphon pisum genome project, hologenome concept was applied to pea aphid and symbioant such as Buchnera aphidicola. Here we screened symbiotic microorganism in four lab strains (two genetically different insecticide susceptible strains, host plant: cucumber and two different host adopted imiacloprid resistance strains, host plants: cucumber and potato) and four field populations (Jeju, Goryeong, Gimjae and Muju, host plant: potato) of cotton aphid based on GS-FLX pyrosequencing which were conducted with universal primer amplified partial fragments of 16S rRNA from total DNA which was extracted from each strain and population. B. aphidicola occupied over 90% of all identified prokaryotic microorganisms which all tested samples. It’s interesting that the ratio of B. aphidicola occupied over 99% in all of the tested lab strains. However, specific enterobacteriaceae occupied six to seven percents of all field populations which closely related endosymbiont of Glycaspis brimblecombei. That means B. aphidicola occupied only 91~92% of all identified prokaryotic microorganisms. Futhermore, other actinobacteridae and bacillaceae also were detected in field populations. The results obtained for these ratios suggested that there has some interaction between symbioant and environment NOT in imidacloprid resistance.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 200-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. The IR showed cross resistances to other neonicotinoid insecticides. IEF and 2DE analyses revealed that general esterase isozyme patterns in IR were almost identical to those of S. Nevertheless, a significantly overexpressed protein spot was detected in IR. To identify differentially expressed genes in IR, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from both IR and S strains, which generated ca. 290 Mb reads for each strain. Generally, most nicotinic acetylcholine receptor subunit genes, such as alpha 2 and beta 1, were more transcribed in S than in IR. In contrast, only alpha 5 subunit gene was 1.8 fold more expressed in IR. Seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in IR. Therefore, this ABCC subfamily, a member of the MRP subfamily which is involved in multi-drug resistance, could be one of the main factors associated with imidacloprid resistance in A. gossypii.

The possibility of commercializing the controlled release of chitosan carrier nano formulation was examined with mortalities and population increase rates of Aphis gossypii and Myzus persicae after treatment of 2 α-cypermethrin nano type formulations of different chitosan carrier molecular weight (M.W. 3,000 and 30,000) and 2 etofenprox nano types of chitosan content (70% and 80%). After 14 days of treatment, α-cypermethrin nano formulation showed over 40% mortality against A. gossypii. Therefore, it was confirmed that the insecticide release was controlled through chitosan carrier. Results of the investigation of insecticidal activity of α-cypermethrin nano formulation showed there were no differences between nano types at 4 days after treatment. However, after 14 days, the population increase rate treated with chitosan M.W. 30,000 formulation was -0.037, much lower than that of M.W. 3,000 formulation with 0.231. The result exhibits that chitosan M.W. 30,000 formulation would be a suitable controlled release formulation. On the other hand, etofenprox formulations didn’t show any significant insecticidal effect or persistency difference against both aphid species.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid resistant strain (IR) was over 200 fold more resistant to imidacloprid compared to the susceptible strain (S) as judged by the LC50 values and IR showed cross resistant to acetamiprid, thiamethoxam, thiacloprid, clothianidin. By using the suppression subtractive hybridization method, a imidacloprid resistant associated cDNA library was constructed in adult cotton aphid. In total 115 differentially expressed cDNA clones were obtained. Any point mutation detected in nicotinic acetylcholine receptor alpha 1~5 and beta 1 subunits in the IR. Based on IEF, the IR general esterase isozyme banding patterns were identical with that of S.

Ten novel microsatellite loci were isolated and characterized from the soybean aphid, Aphis glycines. The soybean aphid was recently introduced into North America where it has become a serious pest of soybeans. This invasive pest has rapidly spread throughout the midwestern United States and southern Canada since 2000. The isolated loci were polymorphic, with two to 18 alleles in 20 individuals from a single population in Korea. The analyses revealed that 19 individuals had different multilocus genotypes, showing expected heterozygosity values ranging from 0.180 to 0.891. We report the development of microsatellite markers for A. glycines potentially suitable for further studies of population structure, dispersal, and host alternation.

The species-rich genus Aphis consists of more than 500 species, many of them host-specific on a wide range of plants, yet very similar in general appearance due to morphological resemblance toward particular morphological types. Most species have been historically clustered into four main phenotypic groups (gossypii, craccivora, fabae, and spiraecola groups). To confirm whether these morphological relationships are correlated with the genetic relationships, we compared the morphometric dataset of 28 characters measured/counted from 33 representative species with a phylogeny reconstructed from the combined dataset of four DNA regions (3,842 bp). The correlation of the rates of evolution between morphological and DNA datasets was highly significant in their diversification. Analysis of trait evolution revealed that the morphological traits found to be significant based on the ANOVA were confidently correlated with the phylogeny. The dominant patterns of trait evolution resulting in increased rates in short branches and temporally later evolution are likely suitable for the modality of Aphis speciation because they have adapted species-specifically, rapidly, and more recently for many different host plants.

For the physiological study on environmental impact of genetically modified (GM) pepper plant on non-target but three-trophically related insect species, we investigated behavioral responses of Aphis gossypii and Aphidius colemani in Y-tube olfactometer to the cucumber mosaic virus (CMV)-resistant transgenic pepper plant (H15 GM line) expressing coat protein gene of CMV and its wild type pepper plant (untransformed, susceptible to CMV pathotype II, P2377 inbred line) in relation to CMV infection. CMV-infected plants were prepared with the 30 min of inoculation by the winged A. gossypii viruliferous or mechanical inoculation using CMV-Fny, and with molecular diagnosis using reverse transcriptase-polymerase chain reaction (RT-PCR) over 2 weeks after inoculation. In this study, time for attraction responses (attraction time) of A. gossypii were not significantly different in the pepper strain, and the virus infection of plant. However, the attraction time of A. colemani was significantly different between the GM plant and the non-GM plant. In addition, the attraction time of A. colemani to the GM plant was significantly decreased according to the CMV infection. For further study, the volatile organic compounds (VOCs) emitted by these plants were collected with an entrainment kit and analyzed by Gas Chromatography (GC) on HP-1 column. The specific VOCs related to CMV infection were detected in the GM plant over 4 weeks after inoculation of CMV in this study. Thus, it is suggested that VOCs of the GM plant in this study may be produced more as a signal attracting A. colemani in relation to CMV infection.

오이모자이크바이러스(Cucumber Mosaic Virus, CMV)에 이병된 착색단고추(Capsicum annuum var. grossum) 의 휘발성 물질(Volatile organic chemicals, VOCs)에 대해 식물바이러스 매개충인 목화진딧물(Aphis gossypii)의 유인반응을 조사하였다. 착색단고추에 CMV를 즙액 접종, 진딧물 보독충을 이용한 접종 및 대조군으로 완충용액만 접종한 처리구와 진딧물 비보독충을 접종한 처리구를 배치하였다. 접종한 CMV와 중복 감염 여부를 우려하여 접종하지 않은 PepMoV를 RT-PCR로 각 단계에서 검정하였다. 분자검정은 상처효과(wounding effect)를 우려하여 유인반응 24시간 이전에 수행하였다. Gas chromatography 분석에 의해 CMV에 이병된 착색단고추는 접종 후 2주 또는 4주에 바이러스 감염에 따른 특이적인 VOCs를 확인할 수 있었다. 특히 접종 후 2주차에 즙액접종과 보독충 진딧물 접종 간에는 발병 특이적인 VOCs의 방출 패턴이 유의적으로 차이를 보였다. 이에 따라 이들 VOCs에 대한 진딧물의 유인 반응을 검정하고자 CMV 이병 식물과 건전 식물에 대한 목화진딧물 유시충의 Y-tube 유인 수를 조사하였다. 그러나 CMV 이병주의 VOCs에 대하여 목화진딧물의 특이적인 유인효과는 나타나지 않았으며, 다만 식물의 생장에 따른 유인수의 증가만 확인 되었다.