목화진딧물(Aphis gossypii)은 고추 재배 초기, 감로 배출을 통하여 잎 표면의 그을음병을 발생시켜 광합성 유발과 작물의 상품성을 저하시킨다. 본 연구에서는 8개의 초위성체 마커(Vanlerberghe-Masutti et al., 1999)를 활용하여 국내 18지역 및 인도네시아 5지역의 고추에서 채집한 목화진딧물의 단편분석을 통해 지역 간의 유전적 유연관계 및 다양성을 분석하였다. 그 결과, 23지역에서 나타난 평균 대립유전자 수 (NA)는 2.750~6.375, 평균 이형접합도 관측치(HO)는 0.425~0.878, 평균 이형접합도 기대치(HE)는 0.354~0.719, 그리고 평균 근친교배(FIS)는 –0.810~0.166의 범위로 나타났다. 근친교배(FIS) 값이 negative으로 나왔다는 것은 근친교배율이 매우 낮은 것을 의미한다. 23지역의 유전적 클러스터 분석 결과, △K의 값은 2로 확인 되었다. 이러한 결과는 조사 지역 개체군간 유전적 구조의 차이가 존재함을 나타내며 개발된 목화진딧물 초위성체 마커가 국내 목화진딧물 개체군의 유전적 구조를 분석하는 데 있어 하나의 좋은 기준이 될 수 있음을 시사한다.

온실재배 오이에 발생하는 목화진딧물의 발생밀도를 추정하는 표본조사법을 개발하기 위하여 2개년(2013-2014년) 동안 주 전체의 잎별 발생밀도를 조사하였다. 목화진딧물의 공간분포 특성은 일반적으로 사용되는 Taylor’s power law(TPL)와 Iwao’s patchiness regression (IPR) 두 가지 방법을 이용하여 분포특성을 조사하였다. 목화진딧물의 주 전체 밀도를 대표할 수 있는 표본단위를 일정 잎 위치의 평균밀도와 주 전체의 잎당 평균밀도와의 일반선형 회귀식을 이용하여 결정하였다. 적정 표본단위는 오이 생육기에 따라 달랐는데, 총엽수가 9매 미만일 경우 2매(중위 엽과 최하위+1번째 엽), 그 이상인 경우에는 3매(위로부터 4번째, 7번째, 최하위+1번째 엽)를 조사하는 것이 적합하였다. 오이에서 목화진딧물의 공간분포 특성은 TPL과 IPR의 기울기가 모두 “1”보다 커 집중분포를 하고 있었으며, 진딧물의 평균-분산 관계를 TPL이 IPR보다 더 잘 설명하 였다. TPL의 기울기와 절편은 연차간에 차이가 없었으며, Green과 Kuno의 식을 이용하여 고정 정확도(D) 수준에서의 축차표본조사법을 개발 하였다. 목화진딧물의 축차표본조사법은 Green의 방법이 Kuno에 비해 더 효율적이었다. 목화진딧물의 일정 평균밀도를 추정하기 위해 필요한 조사 주수는 D값과 잎당 평균밀도가 낮을수록 증가하는 경향이었다. 표본조사를 중지할 수 있는 누적 진딧물 수는 D값이 낮을수록, 조사 주수가 적을수록 증가하는 경향이었다. 목화진딧물 잎당 10마리의 밀도를 추정하기 위해 필요한 조사 주수는 13주이었으며, 이 때 조사를 중지하기 위한 누적 진딧물수는 131마리이었다.

This study was conducted to determine the toxicity to adult Myzus persicae (Sulzer) and Aphis gossypii Glover of 88 plant essential oils and six experimental spray formulations containing bitter orange or marjoram oil was examined using the vapor-phase mortality and spray bioassays. Results were compared with those of two conventional insecticides deltamethrin and dichlorvos. As judged by 24 h LC50 values, bitter orange oil (0.0212 and 0.0192 mg/cm3) was the most active material, followed by marjoram, celeryseed, and cypress oils (0.0239-0.0508 and 0.0209-0.0542 mg/cm3). These essential oils were significantly less toxic than dichlorvos, respectively. These essential oils were consistently more toxic to adult M. persicae in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapor. Bitter orange oil and marjoram oil applied as 1% spray provided complete mortality toward two aphid species adults. Reasonable aphid control in greenhouses can be achieved by a spray formulation containing the 1% oil as potential contact-action fumigant.

Glucose-regulated protein 78 (GRP78) is a member of the heat shock protein 70 (HSP70) family that is specific to endoplasmic reticulum (ER). It is known as chaperones and signaling regulators that respond to ER stresses in vertebrates. However, its function in invertebrates, including insects, is uncertain. Here we determined a full cDNA sequence and the expression patterns of grp78 of Aphis gossypii, which is a major pest of numerous crop plants worldwide. Its cDNA had highly conserved motifs of the HSP70 family and the C-terminal motif of KDEL characteristic of ER-specific HSPs. It showed 98.5% identity with the GRP78 of the pea aphid Acyrthosiphon pisum. Real-time RT-PCR analysis showed that the grp78 level was higher in the fourth instar nymph than in the younger instar and adult stages. Its level was not affected by thermal stress of 10 to 40°C for 1 h. The grp78 level was proportional to the ingestion of a sucrose solution ranging in concentration from 0% to 30% in a Parafilm feeding chamber. In addition, the grp78 level varied among aphids feeding on leaves from 14 different host plants for 24 h; it was higher with eggplant and pepper but lower with pigweed and tobacco than any other plants. Our study suggests that the grp78 level is regulated by nutritional condition of A. gossypii.

목화진딧물(Aphis gossypii Glover) (Hemiptera: Aphididae)은 감귤에서 그을음병을 유발하여 감귤 과실에 경제적으로 피해를 주는 해충이다. 본 연구는 무가온 하우스 감귤에서 계절초기 목화진딧물이 어떠한 경로를 거쳐서 감귤나무에 정착하는지 구명하기 위하여 수행하였다. 감귤나무에서 진딧물 월동알 조사결과 가을순이 난 여름순에서 많이 발견되었는데 월동알은 대부분 조팝나무진딧물이었으며, 목화진딧물 월동알은 발견되지 않았다. 봄순에 정착하는 목화진딧물 유시형 성충은 크게 4월 하순(조기비산)과 5월 하순(지연비산)에 두 차례 관측되었다. 지연비산은 완전생활형 간모세대에서 유시형이 출현하는 시기와 일치하였다. 조기비산 시기에 황색수반트랩에서도 목화진딧물 유시형 성충이 유살되었는데 확실하지는 않으나 월동잡초에서 잔존하고 있던 불완전세대 개체군으로 추정되었다. 결과적으로 무가온 하우스 감귤에서 목화진딧물의 정착은 불완전생활형의 조기비산과 완전생활형의 지연비산으로 일어난다는 것이 확인되었다.

Cotton aphid infests more than 700 plants and a major pest of various horticultural crops worldwide. The glucose regulated protein 78 (GRP78) is a member of heat shock protein 70. Its expression is associated with the nutritional changes as well as environmental stresses. The full sequences of grp78 cDNA of Aphis gossypii was determined. It had conserved motifs of hsp genes and terminated in KDEL which is common to GRP78. Quantitative realtime PCR showed that its level was changed during development and also upregulated by starvation. However, its level was not much changed by heat stress. The level of grp78 can be use to understand nutritional physiology on insects.

The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the imidacloprid-resistant strain. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid had significant effects on the duration of phloem ingestion. In addition, higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior. Temperature and insecticide are two important factors that affect survival, reproduction and other physiological processes of insects. To determine interactions of temperature and insecticide treatment on susceptible and imidacloprid-resistant strains of A. gossypii, adults were exposed to three temperatures (17, 22, and 28℃) or combinations of three temperatures and imidacloprid (LC20), and the expression of several genes (heat shock protein 70, cuticle protein, cytochrome P450, and elongation factor) were analyzed. Additionally, the effect of electron beam irradiation on development, reproduction, and several gene expression of imidacloprid-resistant and -susceptible A. gossypii were compared.

Temperature and insecticide are two important factors that affect survival, reproduction and other physiological processes of insects. To determine interactions of temperature and insecticide treatment on susceptible (S) and imidacloprid-resistant strains (IMI-R) of Aphis gossypii, adults were exposed to three temperatures (17, 22, and 28℃) or combinations of three temperatures (17, 22 and 28℃) and imidacloprid (LC20), and the expression of several genes (heat shock protein 70, cuticle protein, cytochrome P450, and elongation factor) were analyzed. The expression level at 17℃ of heat shock protein 70, cuticle protein, and elongation factor in S strain were up-regulated with increased time and higher than those of IMI-R strain. However, expression of cytochrome P450 was not affected by elevated temperature both S and IMI-R strain. Combined treatment of elevated temperature and imidacloprid were significantly up-regulated only cuticle protein in S strain and higher than those of IMI-R strain.

Aphis gossypii was widely distributed throughout the tropical, subtropical and temperate zone. The chemical control of A. gossypii is becoming problem because it was rapidly appeared resistance expression to chemicals. We will attempt to resolve the this problem using RNAi technique. Besides, RNAi technology can be helpful to study the target genes of A. gossypii. In this study we produce cDNA library construction using gateway cloning system for selecting target gene in order to control of A. gossypii using RNAi. As a result, the 100-400bp of insert size, which is appropriate for RNAi was confirmed. Most of insert gene is associated with A. gossypii, after that insert sequence was compared with DNA databases and EST databases using NCBI blast search. Consequentially, A. gossypii of cDNA library with the titer of 3.15x105 clones were completed. And we will perform the LR recombination to transfer cDNA library into TRV2 (tobacco rattle virus) vector with att site. Then, after performing transformation using Agrobacterium tumefaciens (GV 2260), we inoculated to cucumber with A. tumefaciens. An insecticidal effect or a repellent activity against A. gossypii by changing behavior in transgenic cucumber plants were conformed. Also, the selecting target gene in order to control A. gossypii using RNAi may be provided.

The cotton aphid, Aphis gossypii (Glover), is one of the main pests in various vegetable crops due to insecticide resistance in Korea. Some insect pests noticed neonicotinoid insecticide resistance such as Nilaparvata lugens, Bemisia tabaci and Myzus persicae etc. and the major player which contributed for developing the resistance was over-expression of P450, particularly CPY6 family. However, A. gossypii was a unique case that they developed non-P450 dependent resistant mechanism. Previously we reported that two point mutations (RtoT in nicotinic acetylcholine receptor, nAChR, beta 1 subunit and RtoT with LtoS in a transcript variant) contribute to develop the imidacolprid resistance in A. gossypii. Moreover we surveyed the mutation(s) in various local field populations. Based on the 3D modeling, we hypothesize that RtoT mutation can reduce the imidacloprid sensitivity. A stretch of 33 amino acid was deleted in the N-terminal region of original transcript of nAChR beta 1 subunit that contained RtoT with LtoS mutations in resistant strain. Among the two transcripts, only original transcript differently expressed between imidacloprid susceptible and resistant strain (resistant ratio = 3,800). Six alpha subunit (1∼5, 7) transcript levels were not significantly different between two strains. Therefore mutation and down-regulation of nAChR beta 1 subunit is also associated with imidacloprid resistance in the A. gossypii.

The effect of electron beam irradiation on development and reproduction of susceptible strain (S) and imidacloprid-resistance strain (IMI-R) of Aphis gossypii were compared. Nymphs and adults of S and IMI-R strain were irradiated at target doses of 50, 100, 150, and 200 Gy. When nymphs were irradiated, emergence rate was not affected at all target dose, but number of F1 nymphs was perfectly inhibited at 150 Gy in both strains when irradiated to the adults, longevity slightly decrease at 150 Gy and above. Fecundity was strongly decreased at 100 Gy, but was not completely inhibited even at 200 Gy. Emergence rate of F1 nymph was decreased at 100 Gy and completely inhibited at 200 Gy. However, there was no significant differences on development and reproduction of S and IMI-R strain. We also conducted the comet assay immediately after irradiation and over the following 7 day periods. In addition, we performed quantitative real-time PCR on several genes.

본 연구에서는 목화진딧물(Aphis gossypii)을 접종한 착색단고추(Capsicum annuum L.)에서 방출된 휘발성물질 및 칠성풀잠자리(Chrysopa cognata) 암컷이 분비한 휘발성물질에 대한 칠성풀잠자리 수컷의 반응이 조사되었다. Y-tube olfactometer에서 칠성풀잠자리 수컷 성충은 목화진딧물이 감염되어 있는 착색단고추에 더 많이 이끌렸고, 수 개의 뚜렷한 GC-EAD 반응을 보였다. 이들 GC-EAD 반응을 보인 피크에 대해 GC-MS 및 GC coupled NMR spectroscopy로 분석한 결과, 목화진딧물이 감염된 착색단고추로부터 4-ethylacetophenone, 3-ethylbenzaldehyde, 3-ethylacetophenone 및 4-ethylbenzaldehyde 그리고 칠성풀잠자리 암컷 성충으로부터 (Z,Z)-4,7-tridecadiene, (Z)-4-tridecene 및 (Z)-4-undecene 등이 동정되었다. 야외 포장시험에서 이들 물질 단독으로는 칠성풀잠자리에 대해 유인효과가 없었다. 암컷 성충에서 기원한 (Z)-4-tridecene와 (Z)-4-undecene은 칠성풀잠자리를 유인하지 못하였고, (Z,Z)-4,7-tridecadiene은 nepetalactol의 유인성을 감소시켰다. 하지만 3-ethylbenzaldehyde와 4-ethylacetophenone는 nepetalactol과 함께 혼합하면 칠성풀잠자리에 대한 유인성은 현저하게 증가하였다.

오이에서 가장 피해가 심한 해충인 목화진딧물과 꽃노랑총채벌레에 방제를 위하여 사용하고 있는 천적인 콜레마니진디벌과 미끌애꽃노린재에 대하여 노균병과 흰가루병 약제의 저독성을 평가하여 살균제와 동시에 활용한 목화진딧물과 꽃노랑총채벌레에 대한 천적의 방제효과를 조사하였다. 47종 살균제 중 DBEDC, hexaconazole, pyraclostrobin, tribasic copper sulfate, triflumizole, chlorothalonil, flusilazole, folpet, carbendazim+diethofencarb, cymoxanil+fenamidone, trifloxystrobin은 콜레마니진디벌 머미에 50% 이상의 독성을 보였고 저독성 살균제 중 azoxystrobin이 노균병과 흰가루병을 동시에 방제할 수 있어 천적과의 동시활용 약제로 선발하였다. 꽃노랑총채벌레와 목화진딧물은 천안과 공주에서 4월 상순 동시에 급격히 밀도가 증가하였고, azoxystrobin 50% 액상수화제를 10일간격으로 계속 방제 하면서 콜레마니진디벌을 진딧물 발생초기 1주간격 3회, 미끌애꽃노린재를 발생초기 1주간격 3회 방사 후 천적 밀도를 조사한 결과 목화진딧물과 꽃노랑총채벌레의 밀도를 억제하면서 콜레마니진디벌 머미는 하엽당 최대 18마리, 미끌애꽃노린재는 꽃당 0.5마리를 나타내어 azoxystrobin이 콜레마니진디벌과 미끌애꽃노린재의 밀도형성에 악영향을 주지 않았다. 시설오이에서 콜레마니진디벌과 미끌애꽃노린재에 안전한 선택약제와 천적을 동시 이용할 경우 효과적인 진딧물과 총채벌레 방제가 가능할 것이다.

The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides (6 neonicotinoids, 3 pyrethroids and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids, such as acetamiprid, clothianidin, thiacloprid and imidacloprid. To identify the neonicotinoid resistance mechanisms, we used an imidacloprid-resistant (IMI-R) strain as a model strain. IMI-R showed an extremely high resistance ratio and also cross-resistance to all the test neonicotinoids. However, there was little or no cross-resistance to the other insecticides, including sulfoxaflor. Synergist tests and enzyme activity assays suggested the absence of resistance mechanisms based on enhanced detoxification enzymes, such as cytochrome P450, esterase and glutathione S-transferase. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the IMI-R strain. This R81T point mutation was also found in field populations collected from 5 regions. Therefore, the R81T point mutation was identified as an important mechanism of imidacloprid resistance in A. gossypii.

The effect of electron beam irradiation on development and reproduction of imidacloprid-resistant (R strain) and -susceptible (S strain) Aphis gossypii were compared. Nymphs and adults of R and S strain were irradiated at target doses of 50, 100, 150, and 200 Gy. When nymphs were irradiated, emergence was not affected at all target dose, but number of F1 nymph was perfectly inhibited at 150 Gy in both strains. When irradiated to the adults, longevity slightly decrease at 150 Gy and above. Fecundity was strongly decreased at 100 Gy, but was not completely inhibited even at 200 Gy. Emergence of F1 nymph was decreased at 100 Gy and completely inhibited at 200 Gy. However, there were no significant differences on development and reproduction of R and S strain. We also conducted the comet assay immediately after irradiation and over the following 10 day period. Severe DNA fragmentation in A. gossypii cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. These results suggest that electron beam irradiation induced abnormal development, reproduction, and DNA damage in A. gossypii, but there were no significant differences between R and S strain.

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.