우리나라 작물보호의 역사와 전통을 자랑하는 한국응용곤충학회에서 최고 권위의 송정곤충학상을 수상하게 되어 개인적으로 너무나도 큰 기쁨이고 영광으로 생각합니다. 먼저 영예를 베풀어주신 한국응용곤충학회 회원님들께 깊이 감사드립니다. 솔직한 심경은 학술활동이 그리 뛰어나지 않는 제가 이 큰 상을 받게 되어 죄송하고 면구스러운 마음을 피할 수 없습니다. 송정곤충학상을 제정하시었으며, 우리 곤충학 역사에 빛나는 업적을 남기시고 지도교수이시기도 했던 현재선 교수님과 곤충학 인재의 저변확대에 헌신하시는 박규택 교수님, 그리고 저의 학위과정 이후 줄곧 가르침을 주시는 서울대학교 이준호 교수님 등 많은 은사님, 그리고 곤충학 선배님들께 감사를 드립니다. 그나마 제가 이 자리에 서게 되었던 한 가지 이유라면, 농업해충의 생태와 방제라는 명제에 충실하여 현장에서 농민의 애로문제를 해결하는데 미약하나마 공헌이 되었기 때문이 아닌가 생각이 듭니다. 기후변화의 영향인지 90년 중후반 돌발적으로 나타난 꼬마배나무이, 포도뿌리혹벌레, 애무늬고리장님노린재 등 연구는 가장 기억되고, 현장에서의 살아있는 반응은 오래도록 저에게 자부심을 주는 것이 되고 있습니다. 제주로 정착한 후에는 화살깍지벌레, 귤녹응애, 볼록총채벌레 등 연구를 바탕으로 친환경 감귤 IPM의 기반을 다지기 위하여 노력해가고 있으며, 그 동안 꾸준히 연구의 중심주제로 삼아왔던 해충개체군모형을 현실화하는데도 경주하려고 합니다. 오늘, 송정곤충학상 수상에 대한 감사의 인사로 그동안 제가 다루었던 연구주제를 자성도 겸하여 되짚어 보면서 잠시 잊어졌던 아젠다인 IPM을 되새겨 보고, 새로운 이슈인 생물안보와 기후변화를 넘어 실제현장에 충실한 농업 해충연구의 진로에 대하여 제 생각을 말씀드리고자 합니다. 다시 한번 최고 권위의 송정곤충학상을 받게 되어 영광스럽고 저에게 과분하여 송구한 마음을 감출 수 없으며, 겸손하여 응모에 망설였을 숨어있는 뛰어난 많은 곤충학자들에게 이 영광을 같이 하고자 합니다.
Insects are extremely abundant and diverse. Their ecological importance may outweigh that of other animal groups in both natural and managed ecosystems. To foster beneficial roles of insects while reducing their adverse effects, it is crucial to understand insect behaviors and address its implications for applied ecological questions. Therefore, my research group has focused on studying behavioral ecology of several economically important pests including whiteflies, stink bugs, bean bugs, mosquitoes, and ticks. In this talk, I will present classical and new techniques to study behaviors of the insects and some of the important findings, especially about dispersal and overwintering ecologies.
Resistance development in insect pests against pesticides is one of the most important issues for pest management. Biological control is an attractive strategy for suppressing insects that have become resistant to chemical pesticides. The smaller tea tortrix Adoxophyes honmai (Lepidoptera: Tortricidae) is a serious pest of tea and has acquired resistance to various chemical pesticides, and baculovirus agents have been developed to control this pest in Japan. However, there was great concern about whether A. honmai might also acquire resistance against baculoviruses. To address this question, we developed a model resistant population and studied the mechanism of resistance in A. honmai against baculoviruses. A population of A. honmai that is resistant to nucleopolyhedrovirus (NPV) was selected by exposing a field-collected A. honmai population to the 70% lethal concentration (LC70) of NPV over multiple generations in the laboratory. After 155 generations, the selected strain (Resistant strain; R-strain) showed over 400,000-fold higher resistance to AdhoNPV than the non-selected strain (Susceptible strain; S-strain). In this presentation, mode of resistance of R-strain against baculoviruses were discussed.
Insecticidal crystal toxins from the bacterium Bacillus thuringiensis (Bt) kill insects via a complex mode of action resulting in the creation of cytolytic pores in the membrane of midgut epithelial cells. These toxins are expressed in transgenic cotton and maize which have been adopted worldwide to control lepidopteran pests while reducing dependence on chemical insecticides. However, insect resistance to Bt toxins is increasing in certain key pest species. Beginning with Heliothis virescens, genetic studies in Bt-resistant Lepidoptera and Coleoptera have found mutations in ABC transporters. Cry1A, Cry1C, Cry2A, and Cry3B toxins each appear to target a different member of the ABC superfamily. These studies confirm the essential role of ABC proteins in Bt toxin mode of action. It is proposed that ABC proteins assist in the insertion of the toxin into the midgut epithelial membrane, a crucial step for which the mechanism has not been known in detail. Properties of ABC transporters suggest strategies to increase efficacy of Bt toxins and to delay the evolution of Bt toxin resistance in target insect pests.
The interactions of vector-virus-plant have important ecological and evolutionary implications. In this presentation, I will use the case studies on the whitefly vectors, begomoviruses, and plants to illustrate the complexity, consequences and mechanisms of this type of tripartite interactions. The interactions between begomoviruses and their whitefly vectors via their shared host plants can be mutualistic, neutral or negative depending on the species/strains of each type of the organisms involved. With regard to the mechanisms of plant-mediated positive effects of the viruses on whiteflies, three case studies indicate that suppression of jasmonic acid/salicylic acid related plant defence plays an important role. Our recent studies show that the order of arrival of the interacting vector insects and viruses on the plants may also alter the physiological feature and consequences of the interactions. Future efforts in this area should try to expand the number and diversity of case studies in order to reveal the patterns of interactions, to unravel the molecular and biochemical mechanisms of the interactions using a multidisciplinary approach, and to examine the virus-plant-vector interactions in the field and in natural plant communities.
Virulence of six entomopathogenic fungi was assessed against the 1st instar larva (<5 h old) of oriental fruit moth Grapholita molesta (Busck) in laboratory which is considered as an important pest for stone fruits. Three strains of Beauveria bassiana and each strain of Metarhizium robertsii, Metarhizium bruneum, and Isaria farinosa were evaluated with the concentration of 1×108 conidia/mL at 95.9% RH and 25.4°C by glass scintillation vial assay. Among all, two strains of B. bassiana, ARP14 (87.5%) and A (unpublished) (72.7%), showed highest virulence with 9.8 and 12.6 h of LT50 within 16 h of exposure. However, B. bassiana A showed highest infection rate of 90.0% compare to ARP14 (70.0%) after 14 days. From these results, the two strains of B. bassiana, ARP14 and A, can be used for the control of G. molesta.
The spotted wing drosophila (SWD), Drosophila suzukii, is a severe pest of berry fruits like strawberry, blueberry, sweet cherry and grape in terms of quarantine. For the disinfestation of SWD, methyl bromide (MeBr) is the only option in quarantine practice. However, MeBr's current use will be phased out due to chronic inhalation toxicity to fumigators and related worker as well as ozone depletion properties. To replace MeBr, we evaluated the efficacy of ethyl formate (EF) and phosphine gas (PH3) to all different developmental stages of SWD at practical fumigation condition (>25 ℃). To achieve complete control of all stages of SWD, PH3 required > 6 hr exposure when applied at > 1.0 g m-3. In case of 4hr EF fumigation, the LCt99 (LCt99, 99% lethal concentration × time) of EF to egg, larvae and pupae of SWD was 198.09, 77.42 and 115.55 g·h m-3, respectively.
The diamondback moth, Plutella xylostella, is known worldwide as a pest that affects cruciferous plants. We surveyed insecticide susceptibility in chlorantraniliprole-resistant strain of P. xylostella to 13 insecticides (3 diamaids, 2 synthetic pyrethroids, 2 spinosyns, 1 organophosphorus, 1 carbamate, 1 marcrolide, and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to chlorantraniliprole and flubendiamide. Enzyme assays indicated that glutathione S-transferase (GST) activity in the resistant strain was 2.4 times higher compared with the susceptible strain, whereas no difference was seen for P450 and esterase. Its F1 progeny resulting from reciprocal crosses with a susceptible strain revealed no maternal effects and a diamide susceptible phenotype, suggesting an autosomally almost recessive mode of inheritance.
솔수염하늘소는 소나무에 시들음 증상을 유발하여 괴사시키는 소나무재선충을 매개하는 대표적 매개충이다. 본 연구는 솔수염하늘소의 쏠기와 탈출 행동을 유발시키는 조건을 구명하기 위하여 구속 공간 및 온도를 달리 처리하고 탈출여부를 조사하였다. 솔수염하늘소는 직경 30mm 이하의 공간에 구속되었을 때 장애물을 뚫고 탈출이 가능하였다. 온도 15℃에서는 탈출에 성공하지 못하였으며, 25℃에서 탈출성공률이 높았다. 좁은 공간에 구속되지 않는 경우는 갉는 부위가 집중되지 않아 탈출공을 형성하지 못하였다. 구속된 공간에서 솔수염하늘소는 가운데와 뒷다리 부절을 이용해 좁은 공간에서 몸을 이동시키며 큰턱으로 정면에 있는 장애물을 집중적으로 갉아서 탈출공을 만들고 앞다리를 뻗어 몸을 지탱하면서 빠져나오는 행동을 보였다. 본 연구의 결과는 훈증 대체기술로 제시되고 있는 구속 그물망의 규격을 평가하는데 중요한 기초자료로 활용될 수 있을 것이다.
The sweetpotato whitefly Bemisia tabaci (Gennadius) is a serious pest and vector of various virus causing economic losses in a variety of vegetables in Bangladesh as well as worldwide. In the present study, the mtCOI sequence of B. tabaci was analysed using 70 samples collected from different host plants at 12 districts of Bangladesh. Phylogenetic analysis was shown genetic divergence of our samples was 0.12 – 13.97%. There was three independent clusters such as Asia I, Asia II-1 and Asia II-5 genetic groups. Sequence diversity among three groups was 13.97%, 15.07% and 9.67%. Geographic diversity, for example, Asia I distributed in Central and Northern parts, Asia II-5 Central and Southern parts but Asia II-1 were present everywhere in Bangladesh. There was no B and Q aggressive biotypes in Bangladesh. Most Asia I and II was distributed in southeastern countries including Thailand, Vietnam, Pakistan, China and India. Our results provide understanding of genetic diversity of B. tabaci in southeast area.
Plant virus can enhance its transmission by altering the settling preference of its vector. Nevertheless, most of the studies have focused on the spread of one virus in a field whereas often times there are more than single virus infecting same crop. Furthermore, mixed-infection of multiple viruses tends to cause more severe virus symptoms and changes vector’s biology and behavior different than singular infection. Thus, we are currently investigating the spatial transmission pattern of persistently transmitted potato leafroll virus and non-persistently transmitted potato virus y. However, due to impracticability of obtaining empirical data, we are programming an individual-based modelling software while taking biology of potato, biology and behavior of aphid and different characteristics of two viruses into consideration.
Insect cuticle/exoskeleton covering the entire external surface of the body is essential for protecting insects from various environmental stresses. Tyrosine metabolism plays a major role in not only the darkening of cuticle but also its hardening. In this work, we have focused on the functional analysis of nine genes involved in tyrosine-mediated cuticle tanning (pigmentation and sclerotization) pathway in Tenebrio molitor, which has a unique adult cuticle coloration, dark/black dorsal thorax and elytron, and reddish ventral thorax and abdomen. The temporal and spatial expression patterns of the genes were analyzed by real-time PCR, and RNA interference (RNAi) was performed to study the functional importance of these genes in cuticle coloration and/or hardening in T. molitor. This work was supported by NRFs (NRF-2015R1A2A2A01006614 and NRF-2015R1A6A3A04060323).
톱다리개미허리노린재(Riptortus clavatus)는 콩과 작물을 흡즙하여 작물체를 고사시키거나, 과일을 흡즙하여 반점을 일으키는 등 농작물에 심각한 피해를 주는 해충이다. 이 노린재 해충의 천적인 알깡충좀벌(Ooencyrtus nezarae)은 알에 기생하여 밀도를 감소시키는 잠재적인 생물적 방제인자(biological control agent)로써 역할을 하고 있다. 알깡충좀벌을 인위적으로 대량사육할 수 있는 방법을 개발하고 자, 알기생벌에 기생당한 자연알(natural egg)의 저온보관 방법을 검토하였고, 휘발성 액체로 추출한 카이로몬(kairomone)을 인공알(artificial egg)에 처리하여 알기생벌 의 산란행동 관찰 및 산란을 유도하였으며, 인공먹이(artificial diet)로 알기생벌을 사육하는 과정에서 경험하고 있는 문제점 등을 소개하고자 한다.
Five phaP family genes and one phaR gene have been identified in the genome of Burkholderia gut symbiont. PhaP proteins function as surface proteins of polyhydroxyalkanoate (PHA) granules, and PhaR protein acts as a negative regulator of PhaP biosynthesis. To address the biological roles of four phaP family genes (phaP1, phaP2, phaP3, and phaP4) and the phaR gene during insect-gut symbiont interaction, these Burkholderia mutants were fed to the second instar nymph. The ΔphaR mutant decreased the colonization ability in the host midgut compared to wild-type Burkholderia cells and negatively affected the host insect’s fitness compared with wild-type infected host. These results demonstrate that PhaR plays an important role in the biosynthesis of PHA granules and it is significantly related to the colonization of the Burkholderia gut symbiont in the host insects’ midgut
Dermanyssus gallinae is parasitic to chicken, and they cause many damages such as disturbing sleep reducing for body weight and egg production by blood-sucking. To develop acaricide against D. gallinae, The acaricidal activity of 40 species plant extract were examined. Cnidium officinale extracted by Me-OH showed 82.0% acaricidal activity after treated 48 hrs at 4,000 ppm. The hexane fraction showed 92.4% mortality against D. gallinae at 48 hrs at 2,000 ppm. Purification of the biologically active constituents from the hexane extraction with acaricidal activity was done using silica gel open column chromatography and HPLC. H1122 fraction gave 80.9% mortality to D. gallinae at 400 ppm after treated 48 hrs. H1122 fraction was analyzed by GC-MS and NMR.
Pheromone biosynthesis in the pheromone gland is stimulated by pheromone biosynthesis activating neuropeptide (PBAN) produced in the suboesophageal ganglion. PBAN binds its receptor and transduces biological signal into the molecules for the pheromone biosynthesis. To understand pheromone biosynthesis pathway in legume pod borer, Maruca vitrata, transcriptome of the pheromone gland was analyzed. A total of 191 contigs involved in the pheromone biosynthesis were identified. Putative pheromone biosynthetic pathways for sex pheromone components in M. vitrata were proposed through transcriptomic analysis.
In many insects, female receives a large amount of sperm and ejaculates upon copulation, and keeps them in her uterus for some time, during which she stores sperm. After varying delays, the female removes unused sperm and ejaculates through sperm ejection behavior, which is known as a major mechanism for the post-copulatory sexual selection. In the fruitfly Drosophila melanogaster, timing of sperm ejection behavior is controlled by the diuretic hormone 44 (Dh44) pathway. To identify pathways that regulate Dh44 activities and sperm ejection, here we examine effects of olfactory cues. We will present our recent results suggesting that male odors can be one of upstream signaling pathway that modulates a brain neuropeptide pathway.
The female azuki bean beetle, Callosobruchus chinensis L., a worldwide notorious pest of azuki beans produces sex pheromone having two isomer compounds; (2Z,6E)-7-ethyl-3,11-dimethyl-2,6,10-dodecatrienals (2Z-homofarnesal) and (2E,6E)-7-ethyl-3,11-dimethyl-2,6,10-dodecatrienals (2E-homofarnesal). We synthesized and evaluated the attractiveness of different blends of the two isomeric compounds using Y-olfactometry in laboratory and rocket traps in the field. The attractiveness pattern of the tested blends in Y-olfactometry was found as 1:9≥6:4>9:1 of 2E-:2Z-homofarnesal. Under field condition also, the 6:4 blend was more attractive than 9:1 blend. The result ascertained the enhanced pheromonal activity of homofarnesal with the increased ratio of Z-component in the blend. This provides an opportunity to synthesize Z-rich homofarnresal with less sophisticated and economically feasible Z-selective method.
Morphology of antennal sensilla and their distribution were investigated in male and female adults of Ooencyrtus nezarae, an egg parasitoid of Riptortus pedestris, using scanning electron microscopy. Antennae of O. nezarae was composed of scape, pedicel and seven flagella in both sexes. Six types of sensilla (s. trichodea, s. basiconica, s. chaetica, s. campaniformia, s. sickle-shaped and unknown s.) were identified from both sexes. Among them, s. trichodea and s. sickle-shaped were multiporous, others are not. They distributed in varying numbers. Sexual dimorphism was clearly observed in the distribution of s. trichodea (only on male antennae) and unknown sensilla (only on female antennae). These findings would be helpful for further studies on detailed sex specific-receptive functions of each antennal sensilla.
Maruca vitrata larvae feed on flowers and pods of several leguminous crops, and can severely reduce seed yield. Adult emergence, mating and oviposition behaviors were observed in a 15h/9h=light/dark and 25℃ condition as a base study for monitoring. Emergence occurred mainly during the first five hours of scotophase. Mating occurred from the two days after emergence, and the mated females started to lay eggs from the next day. A maximal mating rate was observed in the night of five days. Mating occurred significantly more often during the time from 2 hours before to 3 hours after lights-off, but older females mated more frequently during the photophase. Electroanntennographic responses of males to some chemicals, and body extracts and volatile collections of females were measured