The small brown planthopper (SBPH), Laodelphax striatellus, is one of the most serious pest insects of rice plants.Buprofezin has been used to control SBPH for more than a decade, however, the occurrence of buprofezin resistant SBPHwas reported recently. To develop an alternative pest control an alternative pest control strategy, RNA-seq of buprofezin-treatedSBPH was performed to screen the insecticidal target genes for RNA interference (RNAi). Six genes were selected fordsRNA synthesis, and applied to SBPH to assess the insecticidal efficacy. Two and three of those dsRNAs showed moderatedand substantial insecticidal activity up to 60% of mortality in one week, respectively. These results demonstrated the potentialof gene screening strategy for the development of RNAi-based pest management program.
Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. Theyproduce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenicfungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanismsof host insect. In this study, Acetone extracts of 189 entomopathogenic fungi cultured on unpolished rice medium werescreened for their juvenile hormone antagonist (JHAN) activities using the yeast-two hybrid system. Among them, 14extracts showed high level of JHAN activities and their insecticidal activities against Aedes albopictus were investigated.
The confused taxonomy of the east Palaearctic pear psyllids, serious pests on cultivated pear, is reviewed. Fifty-sixnominal species have been reported from Pyrus, 25 of which we consider valid and ten as not being associated withPyrus. Our taxonomic revision suggests that, in Korea, four Cacopsylla species develop on pear. Three species occuralso in Japan. New synonyms are suggested and seasonal dimorphism are critically discussed.Key words : Psyllidae, Cacopsylla, taxonomy, host plant, Pyrus, Rosaceae, Manchrian pear, Asian pear, European pear, China,Japan, South Korea, Russian Far East
Amblyseius eharai is a native predatory mite in Korea and a candidate of biological control agent to control spidermites. To evaluate the predation ability of A. eharai, its functional response was tested at 10, 30, 50, 70 and 130 larvaeof Tetranychus urticae. A. eharai showed the Type 2 functional response. The attack rate of female and male A. eharaiwas 0.109 and 0.019, respectively. The handling time of female and male was 0.164 h and 0.234 h, respectively. Theattack rate was significantly different between male and females at 95% confidence interval. However, handling time wasnot statistically different. In comparison with Neoseiulus californicus, attack rate and handling time of A. eharai werebetter than N. californicus. These result should be helpful for evaluation of A. eharai for a biological agent against T.urticae.
We compared the genetic structures of overwintered indigenous Korean and Chinese populations. The eight Koreanpopulations consisted of 33 haplotypes, and 16 haplotypes were newly identified. The genetic diversity of the Koreanpopulation revealed high haplotype diversity and low nucleotide diversity of 0.86 and 0.0024 on average, respectively,due to the high dispersal ability, which is similar to that of the Chinese population (Sun et al., 2015). Comparison with30 Chinese populations using a population tree showed that the Korean populations grouped with 12 Chinese populationsand that 67% were located near Jiangsu province. Moreover, the three frequent migration regions by migratory SBPH,including the Buan, Shinan and Taean counties, were grouped together with high supporting values. These results mightsupport the presence of gene flow between the Korean and Chinese populations by migratory SBPHs.
총채벌레 2종(꽃노랑총채벌레, 대만총채벌레)에 대한 Beauverai bassiana ERL 836 상업화 제품 원제의 약효를반수치사포자수(LS50-1 cm2)를 기준으로 평가하였다. 전반적으로 처리 2일차부터 약효가 나타났으며 번데기와 성충의LS50 값의 범위로 평가 시 번데기에 대한 효과가 성충보다 높은 것으로 관찰되었다. 특히, 4종의 살충제(Acrinathrin,Chlorfenapyr, Spinosad, Thiamethoxam)에 복합저항성을 나타내는 꽃노랑총채벌레 2개 지역 계통에 대해서도 약효를나타내어, 향후 B. bassiana ERL 836 상업화 제품을 활용한 저항성 총채벌레 관리의 정밀 연구가 필요할 것으로판단된다.
It is necessary to understand of temporal and spatial dynamics by establishing a periodical monitoring system for theproper management in small brown planthopper (SBPH). A dataset is including the number of SBPHs by location, collectionmethod [aerial collection net (AeCN) or light trap (LT)] and period (May~Aug.) for five years (2011~2015), and missingvalues were imputed using multiple imputation methods. Of the 15,848 individuals collected, approximately 47% and 52.9%were collected using the AeCN and LT methods, respectively. A high incidence of migratory SBPHs was observed duringJulian days 144-166 using the AeCN method. Generally, the migratory SBPHs from China composed 39.4% of the totalpopulations of SBPHs. These results would provide valuable information to predict the incidence period of migratory SBPHsand establish a proactive management system against SBPH.
2010년 무렵부터 남부지방의 매실 과수원을 중심으로 수확 직전에 대부분의 과실이 낙과하는 원인은 복숭아씨살이좀벌 유충이 과일의 핵 속에서 씨앗을 섭식하기 때문이었고, 유충이 매실의 핵 속에서 성장하기 때문에 효과적인방제방법을 적용하기가 어렵다. 본 연구는 복숭아씨살이좀벌 암컷성충의 산란을 회피할 수 있는 방법을 살펴보고자2016년 전남북 5개 지역의 매실 과원에서 과일의 크기를 측정하였다. 복숭아씨쌀이좀벌 암컷성충의 산란관 길이는평균 5.0mm로 측정되었고, 매실의 핵이 형성되는 시기는 과일의 단경이 8mm 정도였으며, 20mm 이상이 되면 과육의두께가 5mm 이상이 되고 핵이 단단해졌다. 따라서 과일 단경이 8-20mm일 때 산란이 가능하며, 이 시기는 암컷성충의발생일과 거의 일치하므로 50% 우화일(지역별 4월 19일-28일)을 기점으로 5-7일 전과 후 3회 정도 약제를 살포하면산란회피가 가능할 것으로 확인이다.
The two-spotted spider (Tetranychus urticae) is an important pest of many agricultural crops. Laboratory bioassayswere conducted to determine the toxicity of Pyflubumide and Cyenopyrafen against three populations of T. urticae collectedfrom apple orchards. The adults and eggs of three populations all showed susceptibility to Pyflubumide and Cyenopyrafen,as the 50% lethal concentration (LC50) values were all lower than each of the recommended concentrations. There wereconsiderable differences in susceptibility of the acaricides between eggs and adults in different populations. Pyflubumideshowed highest toxicity to adults of Yeongju population (LC50 = 1.40 mg/l) and eggs of Andong population (LC50 =0.54 mg/l). Cyenopyrafen showed lowest toxicity to adults of Andong population (LC50 = 20.29 mg/l) while displayedhighest toxicity to their eggs (LC50 = 2.64 mg/l). These results suggested that T. urticae had not developed resistancein these three regions, Pyflubumide and Cyenopyrafen can serve as alternative chemical candidate for integrated mite managementin apple orchards.
The red flour beetle, Tribolium castaneum, is one of economically important pests and can transmit several fungalspecies with their movement in stored grains. We collected T. castaneum samples from 34 rice processing complexes(RPC) nationwide during 2016-2017 and identified the contamination of fungal species on the surface of T. castaneum.Using sequence analysis of ITS region, 24 fungal genera were found. Among them, the genus Aspergillus spp. (28.8%)was the most frequently presented, followed by Cladosporium spp. (12.3%), Hyphopichia spp. (8.9%), Penicillium spp.(8.2%), and so on. In addition, as a known mycotoxin-producing fungal species, Aspergillus flavus (16 isolates) and Fusariumspp. (3 isolates) were also identified. Our study indicates that T. castaneum would play an important role in the contaminationof fungi and contribute potential production of mycotoxin in storage rice.
Nitiric oxide (NO) and eicosanoids function as crucial immune mediators in insects. This study focuses on cross-talkbetween two immune mediators in term of humoral immune response in Spodoptera exigua. Up-regulation of eight differentanti-microbial peptides (AMP) was observed against bacterial challenge. In contrast, injection of E. coli along with L-NAMEsignificantly down regulation the AMP production whereas D-NAME was not effective. The injection of E. coli withdexamethasone or SNAP also decreased AMP production whereas arachidonic acid (AA) compensated the dexamethasoneeffects. RNA inerferece against SeNOS showed the down-regulation of defensin mRNA level, whereas dsNOS injectionswith AA reversed the gene regulation.
The potato tuber moth, Phthorimaea operculella (Zeller), is a ubiquitous pest on potatoes, tobacco, tomato and othercrops. The small hive beetle (SHB), Aethina tumida Murray, is a pest of European honeybees (Apis mellifera L.) in severalcountries in the world. Propolis is a balm-like substance collected from plants by bees. Its chemical composition variesand depends mainly on the flora in the region in which it is collected as well as the bee species. Hitherto biologicalproperties and the chemical composition of the essential oil extracted from propolis of Korean origin are unknown. Inthis study, while searching for an environmentally friendly method to control these pests we evaluated the repellent effectsof essential oil of propolis collected from Bee Lab of Andong National University and found that it possess repellentactivity against both small hive beetle and potato tuber moth. Moreover, a total of 171 constituents of the oil were identifiedof which 6 were major compounds using GC/MS analysis. We also compared the chemical composition of this oil withthose from 2 Ethiopian regions.
Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) is an important pest in protected culture. We assessed fourrepellents (carvacrol, cis-jasmone, methyl jasmonate, and methyl salicylate) of Frankliniella occidentalis (Pergande)(Thysanoptera: Thripidae) known from literatures to develop a behavioral management tactic against F. intonsa. We measuredthe repellency of F. intonsa that exposed to 100 times diluted repellents on leaf disc. Repellency was 2.60 times higherin methyl jasmonate followed by methyl salicylate (2.16 times), cis-jasmone (2.15 times) and carvacrol (2.08 times) comparedto control. These results suggest that methyl jasmonate can be incorporated as a component of integrated managementof F. intonsa.
Orius minutus (L.) (Hemiptera: Anthocoridae) is a native predators of soft body insects such as mites, thrips, and aphids.We compared 24 h consumption rate of O. minutus with that of a commercialized O. laevigatus (Fieber) on egg andadult stage of Tetranychus urticae Koch (Acari: Tetranychidae). Orius minutus predated 1.4 times more adult T. urticae(58 mites) in 24 h than O. laevigatus. Similarly, O. minutus consumed 128 eggs while O. laevigatus consumed 98 eggsin 24 h without statistical difference. These results suggest that native O. minutus can be applied for the augmentativebiological control after the development of mass-rearing method.
아프리카 원산의 벌집꼬마밑빠진벌레(Small Hive beetle; SHB; Aethina tumida Murray)는 1998년대 미국 양봉장에서발견되면서 서양종꿀벌의 중요한 해충이 되었다. 이 곤충이 2016년 9월 경상북도 밀양시에서 국내 최초로 발견되었다.SHB의 국내 온도 환경에 적응성을 평가하기 위하여, 온도 처리에 따른 발육기간, 사망률을 조사하고, 발육영점온도,발육최적온도, 그리고 고온발육장애온도를 추정하였다. Incubator에서 6개의 온도(15, 20, 25, 30, 35, 38℃)를 이용하였으며, 24plate-wall에 개별사육 하였으며 하단부에 충분한 먹이를 투입하였다. 온도별 사망률은 각각 72.9, 97.9, 97.9,72.9, 54.2%(20, 25, 30, 35, 38℃)였으며, 15℃에서는 모든 알과 20℃에서 1령충까지 사육한 유충 모두 사망하였다.알에서 성충이 될 때까지 기간은 20℃ 47.8±0.4, 25℃ 38.6±0.3, 30℃ 33.5±0.4, 35℃30.6±0.5, 38℃ 28.0±0.6일로 조사되었다. 외부 온도가 15℃이하일 경우 SHB는 발육이 불가능 하며, 38℃ 이상일 경우도 50%이상이 사망하는 것을 보아SHB는 외부 온도 환경에 대한 발육속도와 사망률의 차이가 극심한 것을 확인하였다.
As a broad-spectrum insecticide azadirachtin may cause acute toxicity and alter behavior of natural enemies. We evaluatedthe toxicity of azadirachtin on two egg parasitoids of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), Ooencyrtusnezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae), by pre-treatinghost eggs with five concentrations, i.e., 15, 10, 7.5, 5, and 2.5 mL/L. Azadirachtin significantly reduced parasitism byG. japonicum in 15 and 10 mL/L concentrations than other lower concentrations. Similar effect was also observed inO. nezarae. The parasitism reduction capacity (R) for G. japonicum was 40.8 and 33.1% in 15 and 10 mL/L concentrations,but it was 81.6 and 71.4% in O. nezarae, respectively. Based on the IOBC guideline, azadirachtin can be slightly ormoderately harmful to O. nezarae and slightly harmful or harmless to G. japonicum.
다래(Actinidia arguta)는 전국에 자생하지만 상업적으로 약 30ha가 재배되고 있다. 주요 해충에 대한 친환경 방제법을개발한 결과, 뽕나무깍지벌레 성충과 갈색날개매미충 월동난은 겨울철 기계유유제 살포로 90% 이상, 부화유충은5월 중순 유기농업자재 살포로 92% 이상 방제가 가능하였다. 노린재류는 4월 중순부터 다래 생육후기까지 페로몬트랩으로 효과적으로 포획되었다. 기생봉에 기생된 갈색날개노린재 알은 65.4%로 천적이용 가능성이 높았으나, 썩덩나무노린재의 알은 기생률이 매우 낮았다. 녹응애류, 총채벌레류, 애매미충류는 6월 상순에 동시방제를 하면 방제가90% 이상이었고, 밀도가 높을 경우 8월 중순, 9월 상순에 추가 방제가 필요하였다. 한편, 백색필름을 이용한 과수원바닥 멀칭은 자연초종에 비해 총채벌레류와 애매미충류의 피해과율이 34.9% 낮아 효과적이었다. 유기농업자재로는식물추출물 50%+녹나무오일 5%+목초액 30%, 님 80%, 고삼70%+계피 15%, 고삼 75%+계피 0.5%+채종유 15%,식물추출물 91%+목초액 7.5% 등이 방제효과가 우수하였다.
Potato tuber moth (PTM) is damaging pest of solanaceous crop invasive to Korea. We showed earlier that it inflicteddamage to tomato. So in this study, we evaluated accessions of Solanum lycopersicum (Money maker, Campari, AilsaCraig, LA3475 and e6203) and a wild variety of S. pimpinellifolium for resistance variability. A day old larvae of PTMwere inoculated to leaves and fruits. The result showed high survivability on leaves of Ailsa Craig (95.6%±4.4 SE) andlow on fruits of S. pimpinellifolium (14.0%±6.0). Leaves of LA3475 and fruits of S. pimpinellifolium were less preferred.Volatile compounds could be the cause. Density of trichomes could also influence PTM activity on leaves. These resultsgive us information on resistance variability which could be utilized if there is a host shift due to climate change.
갈색날개매미충 성충을 효과적으로 방제하기 위하여 광에 대한 반응을 실내 시험하여 우수한 광에 대하여 포획장치를 개발하여 포획효과를 현장실증 하였다. 주광색, 녹색, 황색, 청색, 흑색, 적색의 여섯가지 형광등을 이용하여암실에서 각 광원에 대한 갈색날개매미충 성충 유인력을 조사한 결과, 선호하는 광원순서는 흑색>주광색=적색>청색>녹색>황색 이었다. 또 이들 광원간의 선호도 비교시험에서는 주광색 97>흑색 79=적색 79=청색 79>녹색 24>황색13으로 주광색을 가장 선호하였다. 이러한 결과를 이용하여 빛을 이용한 갈색날개매미충 성충유인포획장치를 개발하였다. 포획장치 구성은 주광색 컴팩트램프 2개(30W, 20W), 황색판, 포집수반으로 구성되었으며, 일일 평균 700마리정도포획되었다. 야간기온이 높으면 성충이 활발하게 활동하기 때문에 포획량이 많으나 기온이 낮아지면 포획량이현저하게 줄었다. 시간대별 포획량은 20시~23시까지 세 시간 동안에 75%이상 포획된다. 따라서 광을 이용한 포획장치는 야간기온이 22℃ 이상인 7월 중순부터 8월 하순까지가 효율적으로 포획할 수 있다.
천적 사용을 희망하는 농업인은 대부분 천적만으로 해충밀도가 조절되기를 기대한다. 그러나, 해충의 밀도조절을실패할 경우, 해충방제제를 선택도 고려되어야 한다. 이에 우리는 천적으로 활용 가능한 담배장님노린재와 미끌애꽃노린재에 대하여 타워스프레이를 이용하여 현미식초 등 10종의 유기농업자재별 독성평가를 실시하였다. 직접독성평가결과, 두 곤충 모두 제충국과 데리스에서 100%의 살충율을 보였다. 니코틴 처리구에서는 담배장님노린재는 85.7%의생존율을 보였고, 미끌애꽃노린재는 무처리구와 차이가 없었다. 흰가루병방제제로 활용되는 황토유황 1,000배 처리구에서 담배장님노린재는 71.4%, 미끌애꽃노린재는 66.7%의 생존율을 보였다.