배추나비고치벌(Cotesia glomerata L.)은 배추흰나비(Artogeia rapae L.)와 배추좀나방(Plutella xylostella L.) 유충을 공격하는 내부기생 천적으로, 여름배추를 주로 생산하는 고랭지 채소밭에서 배추흰나비와 배추좀나방을 동시에 생물적 방제하기 위한 천적자원으로서 활용 가능성이 높다. 배추나비고치벌에 대한 온도별 생육반응과 성비, 먹이에 따른 수명을 실험실내에서 조사한 결과, 배추나비고치벌의 알-유충 기간 및 번데기 기간은 20℃에서 각각 12.1 ± 2.1일, 6.4 ± 1.8일이었으며, 생육온도가 높아질수록 짧아지는 경향을 보였다. 이를 바탕으로 산출한 알-유충 및 번데기 시기의 발육영점온도는 각각 7.7℃, 8.5℃였다. 여러 상이한 온도에서 사육한 배추나비고치벌 우화성충의 암수를 조사한 결과, 15℃에 서 61.0 ± 4.5%, 20℃에서 44.2 ± 1.0%, 25℃에서 39.0 ± 2.3%의 성비를 보여 온도가 낮아질수록 암컷의 발생률이 높아지는 경향을 보였다. 배추나비고치벌 성충에 10% 설탕액을 급여한 결과 수명은 20.4 ± 0.2일이었으며, 아무것도 급여하지 않은 경우는 3.6 ± 0.1일이었다. 실내 대량 사육을 통해 확보한 배추나비고치벌 성충을 2007년부터 2018년까지 매년 8월 초에 고랭지 배추밭에 방사하고 노지 기생률을 조사하였다. 그 결과 햇수가 지날수록 노지 기생률이 증가하는 것을 확인하였다(Y=0.2696X+2.8633, R2=0.3994). 가장 높은 기생률을 보인 연도는 2013년의 7.6%이었고, 가장 최근인 2018년에는 6.5%의 기생률을 나타내었다.

When treating the 3rd instar larvae of the diamondback moth (DBM), Plutella xylostella, with sublethal doses (LC10) of chlorantraniliprole, indoxacarb and spinosad via leaf dipping, their tolerance to insecticides was significantly enhanced. By analyzing the differentially expressed genes (DEGs), we found a number of genes that respond commonly or specifically to the test insecticides. With the criteria of p value < 0.05 and Log2FC > 1/ < -1, a total of 476, 367 and 410 genes were determined to respond specifically to chlorantraniliprole, indoxacarb and spinosad, respectively. Gene Ontology (GO) analysis revealed that the cuticle reorganization is commonly associated in all treatments and the oxidative stress-related process is also shown in all insecticides except spinosad. Finally, the DEGs seemingly related with enhanced tolerance were chosen for further characterization, and reliability of the transcriptome data were confirmed by quantitative PCR. The functional categories of these DEGs included mostly detoxification related genes, cuticle proteins, energy metabolism and transcriptional regulation. While the commonly responding DEGs suggest that they are likely involved in defense against common intoxication process, the DEGs specifically responded to each insecticide suggests the presence of unique tolerance mechanisms to each insecticide depending on their different structure and mode of action. Their possible roles in the tolerance/resistance development were discussed.

Various plant extracts were widely used to control plant diseases and insect pests in organic farming system. This study was conducted to evaluate insecticidal activity of plant extracts against three moth in vitro. Insecticidal activity of 21 kinds of farm-made plant extracts including snowbell tree, sweet oleander leaf, sweet oleander and white cedar, collected from farmhouses were tested against diamondback moth (Plutella xypostella) and tobacco cutworm (Spodoptera litura) larvae. In addition, four plant extracts (pyrethrum flower, derris, neem and Sophora flavescens) were tested for insecticidal activity against Potato tuber moth (Phthouimaea operculella) larvae. As a result of insecticidal test on diamondback moth, insecticidal activity of pyrethrum flower extract was found to be 50% or more in diluted 100 times. The insecticidal activities against tobacco cutworm were 92.5% at snowbell tree extract, 77.5% at the sweet oleander leaf and white cedar extracts. Among the plant extracts, insecticidal activity of 300 times-diluted pyrethrum flower and derris extract was 85%, neem and Sophora flavescens extracts were similar to non-treatment. Consequently, pyrethrum flower extract and snowbell tree, sweet oleander leaf, white cedar extracts and pyrethrum flower, derris extracts for controlling diamondback moth and tobacco cutworm and potato tuber moth were selected. We think the selected organic materials can be used to control diamondback moth and tobacco cutworm, potato tuber moth under organic farmhouse condition.

The present study evaluated the susceptibility of field populations of Plutella xylostella and Spodoptera exigua larvae to four diamide insecticides—chlorantraniliprole, cyantraniliprole, cyclaniliprole, and flubendiamide. All the four diamide insecticides induced 100% mortality in the populations from Seongju (SJ) and Geochang (GC) when treated at a concentration recommended for P. xylostella. However, a very low insecticidal activity was observed in the population from Pyeongchang (PC) with 42.3% 3 d after treatment with chlorantraniliprole. Further, the populations of S. exigua from Cheongju (CJ), Jindo (JD), and Yeonggwang (YG) were not completely controlled by the 4 diamide insecticides. A comparison of susceptibility of S. exigua larvae to chlorantraniliprole between 2014 and 2017 showed that chlorantraniliprole induced 100% mortality in all populations in 2014, whereas a very low insecticidal activity was observed among the populations in 2017. This study can serve as a basis to control pests effectively using diamide insecticides.

Streptomyces has been reported to produce various secondary metabolites which have the potential to become environmentally safe insecticides. In this study, 1,274 streptomyces culture filtrates were screened for their JHAN activity in order to identify novel insecticidal compounds. 34 isolates with high levels of JHAN activity were selected, and their insecticidal activities were tested against Plutella xylostella larvae. Among them, IMBL-263 which was revealed to be Streptomyces anulatus by 16s rRNA sequencing showed the highest insecticidal activity. Also, systemic activities of secondary metabolites extracted from the S. anulatus on plant, Brassica napus, were investigated. These results suggested that secondary metabolites from the S. anulatus might be useful for development of novel environmentally benign insecticides.

4종의 diamide계열 살충제를 이용한 배추좀나방과 파밤나방의 지역계통별 감수성을 조사하였다. 배추좀나방의 경우 성주와 거창지역 집단 에서 4종의 약제 모두 추천농도에서 100%의 살충활성을 보인 반면, 평창지역 집단에서는 chlorantraniliprole에 대해 42.3%의 낮은 살충활성을 보였다. 감수성계통 배추좀나방과 저항성비를 비교한 결과 cyclaniliprole은 비교적 4지역에서 유사하거나 낮은 저항성비(0.1~6.3배)를 보인 반면, 평창지역 집단은 chlorantraniliprole (1,196.3배)와 cyantraniliprole (105.6배), flubendiamide (191.6배)은 매우 높은 저항성비를 보였다. 파밤나방의 경우 청주와 진도, 영광지역의 집단 모두 4종의 약제에 낮은 감수성을 나타났는데, 특히 청주와 진도지역의 집단은 flubendiamide에 대해 100,000배 이상의 저항성비를 보였다. 채집 연도(2014년과 2017년)에 따른 파밤나방에 대한 chlorantraniliprole의 감수성을 비교한 결과 2014년에 채집된 집단들은 모두 100%의 살충률을 보인 반면 2017년에 채집된 집단들은 살충활성이 매우 낮게 나타났다. 본 연구결과는 diamide계열 살충제가 빠르게 저항성이 발현되고 있으며 작용기작이 다른 약제와의 교호살포 등 종합적 방제전략을 수립하는데 기초자료가 될 수 있을 것이다.

Actinobacteria have been known to produce variety of bioactive metabolites that include antibiotics and plant growthfactor. Also, Insecticidal compounds such as avermectin and tetranectin have been reported from actinobacteria. In thisstudy, to identify novel insect growth regulator (IGR)-based insecticidal compounds, 1,283 actinobacteria isolates weretested for their juvenile hormone antagonist (JHAN) activity using the yeast-two hybrid β-galactosidase assay. Amongthem, 25 isolates showed high level of JHAN activity and insecticidal activity against 3rd larvae of diamondback moth,Plutella xylostella. These results suggested that actinobacteria could be unparalleled source of novel IGR-based compounds.

The genus Diadegma is a well known parasitoid group in various lepidopteran insect such as Plutella xylostella andsome are known to have symbiotic virus. Previously we reported a novel ichnovirus as named Diadegma fenestrale Ichnovirus(DfIV, 62 segments, 247,238bp) from D. fenestrale which parasitized in the P. xylostella. Here we report another ichnovirus,DsIV from Taiwan strain of D. semiclausum which parasitized in the P. xylostella. Total 64 genomic segments were sequenced,185,053bp from DsIV. Two Ichnovirus showed high similarity in 99 regions in most of segments. We already confirmedintegration of DfIV genome segments into the chromosome from the P. xylostella via genome sequencing of the lepidopteranhost. Therefore some of recombination could be passible inside of the lepidopteran genome.

The diamondback moth, Plutella xylostella is one of the world’s major pests. Economic cost to control this pest wasestimated between US$1.3 billion and US$2.3 billion based on management costs. Conservative estimate included yieldloss caused by 5% diamondback moth was estimated US$4 billion-US$5 billion. P. xylostella was managed by chemicalinsecticide such as organophosphates, carbamates and pyrethroids. But insecticide resistance which is caused by repeatedapplication makes it difficult to control this pest. For environmental friendly control of diamondback moth, entomopathogenicfungi could be used as alternative. We conducted bioassay to select high virulent isolate to larva of diamondback mothwith forty six entomopathogenic fungi which were isolated from soil samples by insect-bait method. As a result of bioassaytwelve isolates was selected as candidate. We investigated control efficacy of these twelve isolates with potted Chinesecabbage at laboratory and greenhouse.

The pheromone biosynthesis in Plutella xylostella is more active in the scotophase than in the photophase, indicating that there may be changes of gene expression in the pheromone glands. To identify genes contributing to change in pheromone production, we analyzed transcriptomes of pheromone glands from both decapitated females (PG-minus) in the photophase and normal ones (PG-plus) in the scotophase. Deep sequencing for mRNAs in the pheromone gland yielded approximately 7.5Gb and 6,671 transcripts showing positive FPKM value were analyzed. Differentially expressed gene analysis revealed that up- and down-regulated transcripts were 310 and 326 in the PG-plus transcriptome, respectively. Genes putatively involved in the pheromone biosynthesis pathway were identified such as acetyl-CoA carboxylase, acetyl-CoA dehydrogenase, fatty acid synthase (FAS), desaturases (Δ9 and Δ 11) and fatty acid reductases of pheromone gland (pgFAR), alcohol oxidase, aldehyde oxidase and aldehyde reductase, etc. Quantitative RT-PCR revealed that expressions of FAS, Δ11 desaturase and pgFAR were significantly higher in PG-plus, suggesting that they may have crucial roles in sex pheromone biosynthesis of P. xylostella

The genus Diadegma is a well known parasitoid group and some are known to have symbiotic virus. A novel IV was discovered from the calyx of D. fenestrale female. This virus was named as D. fenestrale Ichnovirus (DfIV) and its genome contains 62 circular DNA segments with an aggregate size of approx. 240kb. We examined its gene expression patterns depending on the hosts (hymenopteran host, D. fenestrale and lepidopteran host, Plutella xylostella) and stages of P. xylostella based on RNAseq. Among 62 genome segments, only two segments such C15 and D14 were highly expressed in ovary of D. fenestrale. On the other hands, five segments were differently expressed depending on the developmental stages (3 rd and 4 th instar larvae). Additionally we confirmed integration of DfIV genome segments into the chromosome from the Plutella xylostella via genome sequencing of the lepidopteran host.

The diamondback moth (DBM), Plutella xylostella, is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. Chlorantraniliprole is the first commercial insecticide that belongs to the new chemical class of diamide insecticides. In this study, the resistant strain was observed 1578-fold resistance to chlorantraniliprole. Point mutation (G4946E) in ryanodine receptor (RyR) showed a high frequency. 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. In addition, the expression of two GSTs genes was up-regulated. These findings pave the way for the complete understanding of the mechanisms of diamide insecticides resistance in insects.

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.

The diamondback moth, Plutella xylostella (DBM) is a major pest of cruciferous vegetables. The insecticide resistance of this pest is very serious and has been reported in more than 600 cases. It is important to evaluate insecticide response to manage the resistant populations In this study, we investigated the insecticide susceptibility of local DBM strains collected from five major cabbage cultivation area in Korea to the ten commercial insecticides with leaf dipping method . As a result, the resistance ratio(R/R) of almost all the tested pesticides was 0.1∼3.3 (low resistant) and there was no differce within local regions. But dinotefuran showed middle resistance with regional differences (R/R , 5.9∼69.4) For the estimate the control effectiveness, we calculated the log value of the recommendation concentration divided by LC90 of pesticides. The result showed that the efficiency of neonicotinoids was generally low and that of emamectin benzoat every high. In conclusion, neonicotinoids was to use carefully and emamectin benzoate was very good alternative in DBM control in Korea