Fall armyworm (FAW, Spodoptera frugiperda) is a major pest worldwide, and since its first domestic invasion was confirmed in 2019, its damage has been steadily increasing in crops such as corn until recently. In order to provide basic data for the management of FAW, we conducted a comparison of host preference and nutritional composition analysis of corn varieties. A total of 12 varieties of corn were selected for the experiment. To investigate the preference among the varieties, we examined the host preferences at the population level and the individual level, and found no statistically significant differences. In the population-level experiment, the highest damage rate was observed for Saekso 4 and the lowest for Heukgeom 2. In the individual-level experiment, the highest damage rate was found for Kangilok and the lowest for Oryun 2 when using leaves, and the highest for Saekso 1 and the lowest for Dreamok when using stems. As a result, the population-level and individual-level results were not consistent, suggesting that FAW's corn variety preference is not clear and may vary depending on various conditions such as corn tissue. Composition analysis of the 12 varieties showed no correlation between composition and FAW preference among the varieties, and considering the feeding behavior of FAW, which are highly polyphagous, it is recommended to control FAW as early as possible to improve control effectiveness.

Chromosomal level of Korean Diadegma fenestrale (Jeju strain, JK-2023a) of genome assembly was achieved through a combined approach utilizing Nanopore long-read sequencing and Illumina NovaSeq short-read sequencing (approximately 217.2× coverage). The assembled genome spans 221.1 Mb, comprises 68 scaffolds, with most of the genome contained within 11 chromosomal level scaffolds. The completeness of the assembly is reflected in BUSCO assessment, with values reaching 99.6%. Scaffold N50 was 17.4 Mb, and GC % was 40%. RNAseq was performed using RNA extracted from larvae, pupae, and adults at various developmental stages (trimmed RNA-Seq data, 11.3 Gb), and a total of 13,544 genes were predicted by synthesizing the transcriptome information with the annotation information of five closely related species such as, Campoletis sonorensis (GCA_013761285.1), Venturia canescens (GCF_019457755.1), and Nasonia vitripennis (GCF_000002325.3, and GCF_009193385.2). Of these, 13,498 genes were identified by BLAST and are being further analyzed. Although the frequency of DfIV genome integration into the host’s 11 chromosomes varies from 0 to 32%, it was confirmed that all 62 DfIV genome fragments were inserted into the Hymenopteran host genome.

Chromosomal level genome draft was assembled using a Korean Diadegma fenestrale (Jeju strain, KJ09). This assembly was achieved through a combined approach utilizing Nanopore long-read sequencing (approximately 134X coverage) and Illumina NovaSeq short-read sequencing (approximately 83X coverage). The assembled genome spans 243 Mb, comprises 160 scaffolds, with most of the genome contained within 11 chromosomal level scaffolds. The completeness of the assembly is reflected in BUSCO assessment, with values reaching 99.6%. Gene annotation is not completed. A symbiotic virus, Diadegma fenestrale Ichnovirus (DfIV) genome revealed 62 non-overlapping circular DNA segments the aggregate genome size was approximately 240 kb. Although the frequency of DfIV genome integration into the host’s 11 chromosomes varies from 0 to 32%, it was confirmed that all 62 DfIV genome fragments were inserted into the host genome. A total of 123 ORFs were predicted from the DfIV genome and most of those were expressed in the host’s ovary. This result may be contradictory to existing theories, but we propose a new hypothesis that some genes possessed by viruses may play different roles depending on the type and state of the host. Additionally, this phenomenon can be considered in relation to coevolution with the hosts.

Rice serves as the staple food for many Asian countries. However, it faces a significant threat from various Hemiptera species, including Nilaparvata lugens, Sogatella furcifera, Laodelphax striatellus, and Nephotettix cincticeps, which can cause devastating diseases. These species are economically significant pests of rice. Traditional morphology-based methods have proven inefficient in accurately distinguishing these pests at the species level. In this study, we present a successful approach for designing species-specific primers and their application in both general and multiplex PCR as well as loop-mediated isothermal amplification (LAMP) assays, widely adopted molecular tools for species identification. Each primer set incorporates a species-specific sequence of at least 2 base pairs in both the forward and reverse primers. These primers have demonstrated exceptional diagnostic accuracy in conventional and multiplex PCR. Additionally, our study showcases the high sensitivity of LAMP, successfully achieving positive amplification with genomic DNA quantities ranging from 100pg to 10pg. In summary, these techniques provide an efficient means of diagnosing planthoppers in a large number of field-collected or individual samples.

Since 2007, diamide insecticides have been widely used in Korea to control various types of lepidopteran pests including Spodoptera exigua. For nearly a decade, diamide resistance in field populations of S. exigua across 18 localities has been monitored using bioassays. Based on the LC50 values, some field populations showed a high level of resistance against chlorantraniliprole, although regional and temporal variations were observed. To investigate resistance at a molecular level, mutations (Y4701C, I4790M, and G4946E) were examined in the ryanodine receptor (RyR), which is the primary mechanism underlying diamide insecticide resistance. As a result, only I4790M mutation was found in most of field populations. As resistance levels varied significantly despite the uniform presence of the I4790M mutation, we considered the presence of another resistance factor. Further, the I4790M mutation was also found in S. exigua specimens collected prior to the commercialization of diamide insecticides in Korea as well as in other countries, such as the USA. This finding led us to hypothesize that the I4790M mutation were predisposed in field populations owing to selection factors other than diamide use. For further clarification, we conducted whole-genome sequencing of S. exigua (449.83 Mb) and re-sequencing of 18 individuals. However, no additional non-synonymous mutations were detected in the RyR-coding region. Therefore, the high level of diamide insecticide resistance in Korean S. exigua is not caused by mutations at the target site, RyR, but is attributed to other factors that need to be investigated in future studies.

Some of Helicoverpa species (Noctuidae: Heliothinae) are among the worst Lepidopteran agricultural pests in the world, such as H. armigera, H. assulta, H. zea, and H. punctigera. Despite different distribution areas, these species possibly migrate long distances both with and without human transportation, mixing insecticide resistance alleles along the way. As these species are morphologically similar at the larval stage, diagnostic methods have been developed and utilized for their identification. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for rapid and effective species diagnosis, along with PCR, to identify Korean field-collected or overseas samples. Species-specific primers were designed by aligning and comparing the mitochondrial genomes of related species, including four species. There are differences depending on the species and the optimal temperature and reaction time of the LAMP assay, depending on the set of four essential primers. For instance, H. armigera sensitivity is good enough to allow visual discrimination when reacted at 61°C for 30 minutes. This simple and accurate LAMP assay can be used for intensive field monitoring and integrated management of these species.

To elucidate the mechanism of pyrethroid resistance in Helicoverpa armigera, the study explored three possibilities based on deltamethrin as a model pyrethroid; 1) the existence of mutations in the target site of deltamethrin, 2) the existence of variation at the genomic level between insecticide-susceptible and resistant strains, 3) differences in gene expression patterns between the strains. Based on these hypotheses, three levels of resistant strains and a susceptible strain as well as nine Korean field populations were used. As results, 1) any point mutations were not detected in sodium channel gene. 2) based on newly set Korean reference genome (GCA_026262555.1), approximately 3,369,837 and 1,032,689 variants (SNPs and Indels) were revealed from genome and ORFs, respectively. However, any specific variants were not found to be highly correlated with the level of insecticide resistance. 3) based on DEG analysis, some of detoxification enzyme genes were differently expressed particularly cytochrome P450 genes. Therefore, H. armigera possibly acquires deltamethrin resistance through a combination of actions, including over-expression of various detoxification enzymes such as CYP3 subfamilies and cuticular proteins.

Helicoverpa assulta (Lepidoptera: Noctuidae) exhibits a specialized herbivorous diet, primarily targeting select Solanaceae plants. Despite its significant economic impact as a pest, causing substantial harm to crops like hot pepper and tobacco, it has received comparatively limited attention in research compared to its generalist counterparts, H. armigera and H. zea.We introduce a chromosome level genome assembly using a Korean H. assulta (Pyeongchang strain, K18). This assembly was achieved through a combined approach utilizing Nanopore long-read sequencing (approximately 78X coverage) and Illumina NovaSeq short-read sequencing (approximately 54X coverage). The total assembled genome spans 424.36 Mb, designated as ASM2961881v1, comprises 62 scaffolds, with 98.7% of the genome contained within 31 scaffolds, confirming the insect's chromosome count (n = 31). The completeness of the assembly is reflected in BUSCO assessment, with values reaching 99.0%, while the repeat content accounts for 33.01%, and 18,593 CDS were annotated. Additionally, 137 genes were identified within 15 orthogroups that have rapidly expanded in H. assulta, while 149 genes in 95 orthogroups have rapidly contracted. This genome draft serves as a valuable resource to explore various aspects of the specialist's biology, enabling research into host-range evolution, chemical communication, insecticide resistance, and comparative investigations with other Heliothine species.

애긴노린재는 긴노린재과에 속하며 한국을 포함한 동아시아 국가의 다양한 곡물 및 관상용 식물의 주요 해충으로 여겨진다. 본 연구에서는 애긴노린재의 17,367 bp 미토콘드리아 유전체에서 13개의 protein-coding genes, 22개의 transfer RNA genes, 2개의 ribosomal RNA genes 과 non-coding A+T rich region를 확인하였다. G+C content는 23%로 나타났고 다른 긴노린재과와의 염기서열 유사성이 N. cymoides (94.5%), N. fuscovittatus (91.7%)으로 높은 것을 발견하였다. 애긴노린재의 미토콘드리아 유전체 정보는 향후 긴노린재과의 진화 연구와 해충 방제를 위한 정보로 널리 사용될 수 있다.