일반 시설재배지는 겨울을 포함한 저온 시기에 외부의 온도 변화에 영향을 가능한 적게 받기 위한 형태였다면, 최근에는 환경제어기술이 발달하면서 온도, 습도, CO₂, 광량 등을 제어할 수 있는‘스마트팜(Smart-farm)’이 농가에 보급되고 있다. 한편, 토마토 시설재배지에서 많이 발생하는 대표적인 미소해충인 담배가루이와 작은뿌리파리는 유묘나 창문과 출입문의 개폐과정 중에 유입되어 피해를 입히는 것으로 알려져 있다. 스마트팜 내의 해충 발생밀도는 시설재배지 내부의 미소환경에 따라 달라질 수 있다. 따라서 이러한 미소환경의 패턴을 조사하면 좀 더 정확한 해충 발생예찰이 가능할 것으로 생각된다. 본 연구에서는 서로 다른 지역에 위치한 4개의 스마트팜에서 온도와 습도, 그리고 담배가루이와 작은뿌리파리의 해충밀도를 황색 끈끈이 트랩을 이용하여 1주일 간격으로 조사하여 스마트팜 내의 환경변화에 따른 담배가루이와 작은뿌리파리의 수평적, 수직적 밀도분포를 분석하였다.
The multicolored Asian ladybeetle Harmonia axyridis is characterized by polymorphism of the elytral pattern. Melanization in Harmonia axyridis is crucial for their elytral coloration, but the molecular mechanisms are not fully understood in this species. Tyrosine hydroxylase (TH) and dopa decarboxylase (DDC), two key enzymes in the melanin pathway, convert tyrosine and dopa into dopa and dopamine, respectively. In this study, it was to determine the role of TH and DDC of Harmonia axyridis (HaTH and HaDDC) in body and wing pigmentaion produced via melanin pathway. The cDNA sequences of HaTH and HaDDC were cloned to perform RNAi-based functional analysis. Injected dsRNA to the 4th larvae caused knockdown of target genes, and it was verified by quantative realtime PCR. Both TH and DDC RNAi adult show loss of black pigmentation in their body and wing pigmentaion. These results is expected to be helpful to investigate polymorphism by melanin pigment in Harmonia axyridis.
For the studying of effects of matrine and azadirachtine against Aphidius colemani, it was conducted to test the toxic effect of ecofriendly materials. Matrine and azadirachtine are active ingredient of the most commonly used eco-friendly insecticidal materials against insect pests. The effects of materials are investigated by spraying solution to mummies and adults in laborartory condition (Temp: 25℃; 16L:8D; RH: 50-60%). Each materials was diluted and treated with 5 concentrations, 10 wasps for each replications and 3 replications for each concentration. Fitness of A. colemani was assessed by measuring survival rate, emergence rate, longevity and fecundity. Wasps adults were used for experiments within 48 hours after their hatching. Emergence rates were checked for 12 days after spray to mummies of A. colemani, and survival rates were checked at 24 and 48 hours after vial test for adult parasitoids with 10% sugar solution. Adult wasps were exposed to dry residue of material for 24 hours. Longevity was monitored every 12 hours and fecundity was measured by the number of mummies produced by A. colemani adults.
가루깍지벌레(Pseudococcus comstocki)는 전 세계적으로 배를 포함한 과수와 작물에 피해를 주는 해충으로 성페로몬을 이용하여 가루깍지 벌레를 방제하기 위하여 가루깍지벌레 수컷의 온도별 발육과 교미비행 및 비행에 미치는 영향을 조사하여 방제에 적용하고자 본 연구를 수행하였다. 가루깍지벌레의 온도별 발육기간은 15℃에서 알이 산란 및 부화되지 않았고, 25℃까지 발육기간이 짧아지다가 30℃에서 다시 늘어났다. 산란수는 25℃에서 평균 482개로 나타났으며, 성비는 15℃, 20℃, 25℃에서 50%에 육박하였지만 30℃에서 수컷의 성비가 37%였다. 비행패턴은 오전에 비행이 많았고 그 중에서도 해가 뜨고 난 직후 2시간 이내에 가장 많았다. 광주기가 달라지더라도 해가 뜨고 난 후 4시간 사이에 비행하 는 개체가 많았다. 암조건만에서 암수를 사육하는 경우에도 비행이 일어났다. 상승 바람의 풍속에 따른 가루깍지벌레 수컷의 비행을 조사한 결과, 0.5 m거리 일 경우 1.5 mph 이상에서는 비행을 하지 못하였다. 배원에서 수컷의 비행은 2 m 이상에서는 채집되는 개체가 거의 없었고 1.5 m에서 가장 많은 수가 포획되어 트랩을 설치하는 높이로 가장 적합하다고 판단된다. 수컷 방사지점과 트랩 사이의 비행가능 거리를 보면, 0.5 m, 1 m, 5 m까지는 트랩에 잡히는 수가 많았고 10 m, 15 m, 20 m에서 적었다. 다만, 50 m까지도 채집되는 것으로 보아 성페로몬 트랩을 이용하여 50 m 이상 떨어져 있는 수컷도 유인할 수 있을 것으로 사료된다.
작은뿌리파리는 넓은 기주 범위를 가지며 시설하우스에서 피해를 주는 주요 해충이다. 이를 해결하기 위한 방제 방법을 연구하기 위해 재현성 있는 사육방법을 개발보급시켜야 할 필요가 있다. 본 연구는 실내에서 작은뿌리파리에 대한 대량사육시스템을 구축하고 생태적 특성을 연구하였다. 작은뿌리파리의 온도별 발육을 조사한 결과, 20℃에서 부화율, 용화율, 우화율이 가장 높았으며, 성충을 제외한 발육기간이 20.8일로 가장 짧았다. 성충수명은 온도가 높아질수록 수명이 짧아졌으며, 20℃에서 평균 144개로 가장 많이 산란하였다. 작은뿌리파리 유충 사육배지 조성이 유충 발육에 미치는 영향을 알아본 결과, 물한천배지와 감자디스크배지가 부화율 84.7, 84.4%로 높았으며, 유충기간은 감자디스크배지가 14.7 일로 가장 짧았다. 용화율, 우화율은 감자디스크배지가 85.2, 82.6%로 가장 높았고 산란수도 125.6개로 가장 높았다. 우화케이지에서 생육배지를 선발한 결과, 우화율은 원예용 상토 50% + 톱밥 25% + 잘게 간 감자 25% 배지가 접종 14일차의 우화율이 88.4%로 가장 높았다. 우화케이지의 생육배지 적정 접종밀도는 유충 1,000개 접종 시 84.7%로 가장 높았고, 유충 3,000, 5,000, 7,000개 접종시 81.4, 58.8, 38.7%로 유충 접종량이 많을수록 우화율이 낮았다. 위 실험 결과에 따라 작은뿌리파리의 대량사육시스템의 사육단계별 자세한 사항을 정리하였다.
토마토는 어느 정도 높은 온습도에서 잘 자라기 때문에 주로 비닐하우스에서 재배되어왔다. 최근에는 정보통신기술 (ICT)의 발달로 온도, 습도, CO₂등의 환경요소를 원격으로 조절하여 힘과 시간을 덜 소모하고도 작물의 생육환경을 편리하게 관리할 수 있는 스마트팜(Smart farm)이 늘어나고 있다. 본 연구에서는 토마토 비닐하우스 및 스마트팜에서의 위치별 온․습도와 토마토의 주요 해충인 담배가루이와 작은뿌리파리의 발생량 및 시설 내 발생분포를 조사하였다. 조사결과, 시설재배지 내의 위치에 따라 온․습도 및 해충 발생량에 차이가 나타났으며, 작은뿌리파리의 경우 시설의 가장자리 및 낮은 위치에서, 담배가루이는 시설의 중앙부 및 높은 위치에서 밀도가 높게 나타나는 경향을 보였다.
Harmonia axyridis have become extremely popular through their extensive elytra and spot variation for many years. However, phenotypic polymorphism and striking visual phenotypes are not yet to be extensively studied. With growing attention to polymorphism of H. axyridis, it is imperative to study involved in genomic research in order to elucidate the molecular mechanisms underlying the diversity of elytra variation. To figure out suitable approach for analyzing genes of H. axyidis, we assessed RNAi as a tool for functional analysis. In order to demonstrate the utility of RNAi technique on H. axyridis, we conducted cDNA library screening to affirm silencing effect. We choose random genes from cDNA clones and the random genes were synthesized into dsRNA. After the injection of dsRNA into last instar larvae, we observed morphological defects or deaths. To investigate the effectiveness of knockdown in H. axyridis, we performed quantitative real time PCR on H. axyridis that appears the most distinctive features. These results provide that RNAi is highly applicable in H. axyridis and it will be useful for the gene functional analysis.
무당벌레(Harmonia axyridis)는 종내에서 초시색상패턴이 매우 다양하게 존재한다. 본 논문에서는 서로 다른 색상패턴의 무당벌레를 대상 으로 amplified fragment length polymorphism (AFLP)을 실시하여 무당벌레의 초시색상 패턴간 유전형질의 차이를 확인하고자 하였다. 총 28 개의 프라이머 조합으로 실험을 실시한 결과, 총 2,741 개의 밴드가 검출되었다. 그 중 20 개의 밴드(S1-S20)만이 특정 색상패턴에서 나타났다. 이들 가운데 9 개의 밴드를 색상에 연관된 AFLP 후보 지표로 선발하였다. 밴드 가운데 S1과 S2, S20은 Succinea 1, 2 변이형에 공통적으로 나타났으며, S3와 S5는 Conspicua 변이형에 특이적이었다. 또한 S13는 Spectabilis 변이형에, S15와 S18, S19는 Succinea 2 변이형에 특이적이었다. 특정 색상패턴에만 나타나는 9 개의 AFLP 지표들은 cloning을 통해 염기서열 분석을 실시하였고, GenBank를 이용해 다른 염기 서열과 비교를 해보았지만 아무런 상동성도 찾을 수가 없었다. 무당벌레 종 내 유전적 다양성을 평가한 결과, Spectabilis가 Conspicua보다 Succinea 변이형에 높은 유사성을 보였다. 색상에 연관된 AFLP 후보 지표를 기준으로 sequence characterized amplified region (SCAR) 지표로 변환하여 9 개의 AFLP 분자지표들 가운데에서 5 개만이 SCAR 지표로 전환될 수 있었으며, 이를 통해 AFLP 지표가 무당벌레의 색상과 연관되어 있는지 확인할 수 있었다.
꽈리허리노린재는 가지과 및 메꽃과 기주에 피해를 주는 해충이다. 꽈리허리노린재는 실내의 25℃ 조건에서 1세대는 평균 76일정도 소요 되며, 성충으로 월동하기 때문에 수명이 길고, 일정한 주기 없이 알을 덩어리로 산란한다. 주로 잎 뒷면에 산란하며, 암컷 한 마리당 평균 195개, 최대 468개까지 산란하는 것으로 나타났다. 또한, 온도가 높아질수록 부화율은 높아지며, 발육기간은 짧아졌지만, 25℃를 제외한 다른 온도에서는 탈피율이 30%이하를 나타냈다. 위 결과를 토대로 선형모델로 추정한 결과 발육영점온도는 13.9℃, 유효적산온도는 526.3DD를 나타냈다. 고추재배지에서월동 성충이 6월 말 평균기온 25.7℃에서 나타나기 시작하여, 9월초에 가장 높은 밀도를 나타내었다. 부화한 개체들은 성충이 될 때까지 이동성이 적었으며 밀집하여 분포하였다. 집단을 형성하는 요인을 알아보고자 Net cage와 Y-tube olfactometer를 이용한 행동실험 결과, 암컷은 수컷과 암컷이 모두 있는 곳을 선택하였지만, 수컷은 암컷과 수컷이 모두 없는 곳을 선택하였다. 수컷이 새로운 기주를 찾아 정착하면, 암컷은 기주를 독점한 동종이 많이 있는 기주를 찾아가는 교미와 관련된 행동을 나타냈으며, 통신화합물의 영향은 알 수 없었다. 집단이 미치는 영향을 알아본 결과 꽈리허리노린재는 좁은 공간에서 집단으로 사육시 약충의 발육기간이 길고 우화율이 높아지는 반면, 개체 사육시 발육기간이 짧고, 우화율이 낮게 나타났다. 반면에 넓은 공간에서는 집단으로 사육 시 약충의 발육기간은 짧고 우화율은 낮게 나타났다.
갈색날개매미충의 방제전략을 확대하기 위하여 박하유에 대한 기피 효과를 살펴보았다. 23종의 방향유를 Y-tube olfactometer를 이용하여 후각 검정을 실시한 결과, 박하유(peppermint oil)와 lemongrass oil을 제외한 21종의 방향유는 갈색날개매미충에 대하여 기피반응이 나타나지 않았다. 단지 박하유만이 80% 이상의 기피효과가 관찰되었다. 박하유의 처리량에 따른 기피반응을 조사한 결과, 갈색날개매미충은 0.1, 0.5, 1 ㎕ 처리시 기피율이 점차 높아졌으며, 10 ㎕(76.47%) 처리량에서 높은 기피효과를 보였다. 박하유에는 1,8-cineole(4.7%), menthone(23.9%), iso-menthyl acetate(8.0%), menthol(53.7%) 등이 함유되어 있었다. 이들의 주요 성분함량을 혼합하여 Y-tube olfactometer를 이용하여 후각 검정한 결과, 5 ㎕ 처리시 76.2%의 높은 기피율을 보였다. 박하유는 야외에서 갈색날개매미충의 기피 및 산란 기피효과를 보였으나 단시간에만 활성이 강한 점과 약해의 가능성을 보아 제형 개발의 필요성이 대두된다.
담배가루이(Bemisia tabaci)는 외래해충으로 바이러스벡터로 작용하여, 토마토의 토마토황하잎말림병바이러스(TYLCV)를 비롯한 약 100여종의 바이러스를 매개하는 중요한 해충이다. 본 연구에서는 VIGS vector를 이용하여 담배가루이 방제를 위한 target 유전자들을 선발하기 위 해 gateway system을 이용한 담배가루이 cDNA library 제작을 시도하였다. 첫 번째 방법으로 oligo d(T) primer를 사용하였을 때, 평균 약 1 kb의 insert와 1.4×10 4 cfu의 titer를 확인하였다. 그러나 insert size가 너무 커서 적절하지 않았다. 두 번째 방법으로 attB-N25 random primer를 이 용하고, sonication을 6초 실시하여 다시 진행하였다. 그러나 확인되는 insert size는 다소 컸고, 몇몇은 insert가 너무 작아서 밴드가 확인 되지 않았으며, 1.04×10 5 cfu의 titer를 확인할 수 있었다. 세 번째 방법으로는 oligo d(T) primer를 이용하였고, sonication을 2초 실시하였다. 그 결 과 300 bp~600 bp size의 insert가 확인되었으나, electro transformation을 사용한 첫번째, 두번째 방법에 비해 heat shock transformation을 사용하여 titer가 5.2×10 2 cfu로 매우 낮은 것을 확인 할 수 있었다. 결과적으로 cDNA library를 만들 때 먼저 random primer를 사용하여 First strand를 합성하여 poly A를 제거하고, 다음으로 sonication을 1초 실시하여 300~700 bp정도의 적절한 size의 insert를 생성하고, 마지막으로 electro-transformation을 실시하여 transformation 효율을 높인다면 VIGS vector에 적합한 cDNA library를 만들 수 있을 것으로 사료된다.
Multiple starters consisting of two Bacillus amyloliquefaciens strains (MJ1-4 and EMD17), Pichiafarinosa SY80, and Rhizopus oryzae were used for Doenjang making. Bacillus strains were selected based on their abilities to inhibit toxinogenic fungi and Bacillus cereus, fibrinolytic activity, and their ability to confer good flavor to Cheonggukjang. P. farinosa SY80 and R. oryzae, previously isolated from soy sauce, were selected because they were not inhibited by two bacilli. Doenjang was prepared by inoculation of multiple starters (A1 Doenjang). Control Doenjang was prepared by inoculation of B. subtilis KACC 16750 (Natto strain) and Aspergillus oryzae KCCM 60166 (A2 Doenjang). Another control (A3 Doenjang) was prepared by inoculation of microorganisms present in rice straw. Doenjang samples were fermented for 70 days at 20℃. pH of 3 samples decreased from the initial value of 6.4 to 5.8~6.0 and titratable acidity (TA) increased from 0.6 to 1.1~1.3. The amount of amino-type nitrogen increased during fermentation. There were slight differences in moisture, crude-protein, and crude-fat contents after 70 days. Contamination of fungi was observed only in A3 Doenjang and B. cereus was not detected from all 3 samples. A1 Doenjang showed the highest fibrinolytic activity and A2 Doenjang the second. These results indicate that Doenjang made with carefully selected starters was functionally improved and microbially more safe.
Bacillus thuringiensis (Bt) is a gram-positive bacterium that produces parasporal crystal proteins known as endotoxins or Cry proteins. The Cry protoxins are then cleaved by insect midgut proteinases to form active Bt toxins. The activated Cry protein then binds to specific receptors at the midgut epithelium. Cadherin-like and aminopeptidase N (APN) proteins are involved in Bt toxin binding by interacting sequentially with different toxin structures. Aminopeptidase N (APNs) from several insect species have been shown to be putative receptors for these toxins. We have characterized four different midgut APNs(APN1, APN2, APN3, APN4) cDNAs from S. exigua. Forward primers and reverse primers for confirmation of four different midgut APNs were designed based on their sequences cloned from the cDNA libraries. Quantitative RT-PCR procedures includes 42℃ for 20min (cDNA synthesis), 99℃ for 5min, and 35 cycles (94℃ for 1min, and 60℃ for 50 s) for collection. Four aminopeptidase N isoforms were confirmed with qRT-PCR. Sequence analysis was performed by BlastX search the National Center for Biotechnology Information(NCBI) nucleotide. Furthermore, double-stranded RNAs(dsRNAs) were synthesized. DsRNAs were determined for bioassay.
Pyrifluquinazon, as a quinazinalone chemical group, based on a new mode of biological activity. It is reported that mode of action is modifies insect behavior, rapidly stopping feeding such that insects starve to death. Time-release feature and mortality effect on M. persicae using different pyrifluquinazon nano type and non-nano type were compared. Pyrifluquinazon nano type was formulated with different molecular weight and density of used chitosan (CS 30000 0.1% and CS 3000 0.3%). In the CS 30,000 0.1%, the mortality was weakly occurred at early time, but steadily increased after 4days. Finally, we confirmed more than 70% mortality as a peak at 16days. In CS 3000 0.3%, the mortality showed about 70% until 18days as a effective controlled release. Also, We examine time-release feature and mortality effect on M. persicae according to the different pyrifluquinazon nano type(CS 30000 0.1% and CS 3000 0.3%) of concentrations. The CS 30000 0.1% bioassay results of different concentration were showed that the highest concentration(100ppm) was measured better mortality than other concentration at 0 day, but cannot confirm different effect about dissimilar concentration. However, increasing rates of M. persicae were low as treatment concentrate was high. In CS 3000 0.3% 100ppm concentration bioassay result, aphid mortality reached peak at 24 days and increasing rate also low. Additionally, for the comparing of bioassay and feeding behavior of M. persicae against pyrifluquinazon nano types and non-nano type, EPG technique was carried out. In case of non nano type, feeding inhibition efficacy was showed during 4 days after treatment, but appeared similar level with control after 10days. In CS 3000 0.3% 50ppm, residual efficacy was specially showed until 28days after treatment whereas treatments with CS 30000 0.1% were similar to the control after 22days. These result show that the change of feedinng behavior and motrality of M. persicae is correlated with the change of nano type or non nano type of pyrifluquinazon.
Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure is largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filaform antennae of males (1,515.20±116.48 ㎛) are longer than females (1,275.06±116.42㎛). Antennae of this species is made up of scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. Female and male antennae of A. colemani has samely seven types of sensilla. We classified sensilla placodea, Bohm bristles, 2 types of sensilla coeloconica, , 2 types of sensilla basiconica as with a tip pore and with wall pores, sensilla trichodea. In addition, the possible functions of the above sensilla types are discussed in light of previously published literature; mechanoreception(Bohm bristles, sensilla coeloconicaⅡ and sensilla trichodea) and chemoreception(sensilla coeloconicaⅠ, sensilla basiconicaⅠ,Ⅱ and sensilla placodea). Future studies on the functional morphology of the antennal sensilla of A. colemani using transmission electron microscopy (TEM) coupled with electrophysiological recordings will likely confirm the functions of the different sensilla identified in this study.
The multicolored Asian ladybird beetle, Harmonia axyridis, is a generalist predator of aphids also, shows a high level of phenotype polymorphism in color pattern of elytra. Although, it is not sure about genetic information of color polymorphism, it has been confirmed that this phenomenon comes from their genetic traits. The color of H. axyridis elytra is mainly composed of black and red pigment. Phenoloxidase (PO) plays an important role in many insect physiological functions, i.e. sclerotization and pigmentation of cuticle and melanization of parasites. Following activation, PO catalyses the hydroxylation of tyrosine and subsequent oxidation of phenolic substance into quinines, which are further converted to melanin. However, the molecular bases of H. axyridis color pattern formation are almost unknown but it may be that the different pro-POs have different expression. In this study, total RNA samples from four each color pattern individuals, for example, succinea 1, succinea 2, conspicua and spectabilis was extracted. A cDNA enconding pro-PO was molecular cloned from each color pattern of H. axyridis and its putative amino acid sequence shared homology with pro-PO of other insects. We are pursuing to elucidate that their pro-PO sequence will be similar with those other insect PPO sequence. There are also regions of high sequence similarity, including putative activation site and two copper binding sites.
Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure is largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filaform antennae of males (1,565.60± 194.64㎛) are longer than females (1,303.83±156.41㎛). Antennae of this species is made up of scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. Female and male antennae of A. colemani has samely ten types of sensilla. We classified 3 types of sensilla trichodea as without pores, with a tip pore and with wall pores, 3 types of sensilla coeloconica, 1 sensilla placodea and 1 Bohm bristles. In addition, the possible functions of the above sensilla types are discussed in light of previously published literature; mechanoreception (Bohm bristles and sensilla coeloconica) and olfaction (sensilla trichodea and sensilla placodea). Future studies on the functional morphology of the antennal sensilla of A. colemani using transmission electron microscopy (TEM) coupled with electrophysiological recordings will likely confirm the functions of the different sensilla identified in this study.
To identify DNA markers linked to a elytra polymorphism, amplified fragment length polymorphism (AFLP) analysis was performed on DNA samples from four each colour pattern individuals (2 females and males), for example, succinea 1, succinea 2, conspicua, and spectabilis. As a result of performing AFLP analysis with the restriction endonuclease combination EcoRⅠ and Mse I, total of 2,269 AFLP fragments which were specific to succinea, conspicua and spectabilis was identified using 24 different AFLP primer combinations. Among these 2,269 fragments, 16 bands which were the most specific to one color patterns were isolated, cloned and sequenced. Subsequent UPGMA cluster analysis revealed that population of H. axyridis was divided four major group and these genetic tree showed that H. axyridis elytra colour diversity was affected by genetic polymorphism. It is considered that these genetic analyses may be facilitated the understanding of molecular genetic mechanism related with the wing colour pattern formation in this species.
Sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a serious pest of many economically important crops. The insect has developed resistance to chemical insecticides. Therefore, the development of microbial agent is necessary. Among the several entomopathogenic fungi, Lecanicillium lecanii Btab01 which has high insecticidal activity was carried out this experiments. To develop mass culture, we subcultured L. lecanii Btab01 on PDA, TSA, SDA+Y, RA and GSA media at 25℃ incubator to select the optimal solid culture medium. Hyphal growth was measured every 3 or 4 days. L. lecanii Btab01 grew fastest in RA, followed GSA, SDA+Y, PDA and TSA. L. lecanii Btab01 was cultured on PDB, TSB, SDB+Y, RB, GSB media at 25℃, 180rpm shaking incubator to select the optimal liquid medium. Spore germination was measured by spread plate method every 12 or 24 hours. Spore germination appeared 7.8×108 CFU/ml after 4 days in RB, followed GSB (5.5×108 CFU/ml), SDB+Y (2.7×108 CFU/ml), TSB (1.7×108 CFU/ml) and PDB (0.6×108 CFU/ml).
After treatment with imidacloprid, there were clear differences in the time to the first reaction of Myzus persicae among the concentrations treated. The time taken for the proboscis of the aphids to penetrate, during the recording plants increased as the imidacloprid concentration increased. Imidacloprid concentration inflow into a leaf was investigated using high-performance liquid chromatography, and the residues of the imidacloprid varied slightly with the different concentrations treated. However, the inflow rates of this insecticide into a leaf increased as the dipping times increased. Furthermore, it was shown that there was no relationship in inflow concentration between the concentrations and times of treatment. However, the concentration in the leaf differed according to the dipping time. Judging from the fact that the first reaction behavior against imidacloprid displayed at an inflow concentration of 0.32-0.35 ㎎/L, we concluded that inflow concentrations causing the first reaction of the aphids to the insecticide were much lower than the concentration treated. The general feeding characteristics of the aphids indicated that xylem and/or phloem feeding behavior continued after a series of probing behaviors and stylet activity during the first 3 h from the start of EPG recording. After 90 min treatment with imidacloprid, feeding behavior over the next 30 min indicated a significant increase in the withdrawal of the stylet from the plant at all treated concentrations. Xylem and/or phloem feeding patterns were significantly decreased during this time. In particular, the proportion of xylem feeding differed according to the concentration of imidacloprid.