ABSTRACT
Rapid assessment of crop damage is essential for successful management of insect pest outbreaks. In this study, we investigated the use of an unmanned aircraft system (UAS) and image analyses to assess an outbreak of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), that occurred in soybean fields in South Korea. A rotary-wing UAS was deployed to obtain a series of aerial images over 31 soybean blocks. The images were stitched together to generate composite imagery, followed by image analyses to quantify soybean defoliation. An economic analysis was conducted to compare the cost of the aerial survey with that of a conventional ground survey. The results showed that the aerial survey precisely estimated the defoliation compared to the ground survey, with an estimated defoliation of 78.3% and a range of 22.4-99.8% in the 31 blocks. Moreover, the aerial survey followed by image analyses was found to be more economical than the conventional ground survey when the number of target soybean blocks subject to the survey was more than 15 blocks. Our study clearly demonstrated the effectiveness of using an autonomous UAS and image analysis to conduct a low-cost aerial survey of soybean damage caused by S. exigua outbreaks, which can inform decision-making for S. exigua management.
ABSTRACT
The fall armyworm [FAW, Spodoptera frugiperda (J E Smith)], a moth native to America, has spread throughout the world since it was first discovered in Africa in 2016. The FAW is a polyphagous migratory pest that can travel over long distances using seasonal winds or typhoons because of its excellent flying ability, causing serious damage to many crops. For effective FAW control, accurate species identification is essential at the beginning of the invasion. In this study, the FAW-specific gene Sf00067 was discovered by performing bioinformatics to develop a fast and accurate tool for the species-specific diagnosis of this pest. An Sf00067 loop-mediated isothermal amplification (LAMP) assay was developed, and optimal conditions were established. The Sf00067 6 primer LAMP (Sf6p-LAMP) assay established in this study was able to diagnose various genotype-based strains of FAW captured in Korea and FAWs collected from Benin, Africa. Our FAW diagnostic protocol can be completed within 30 min, from the process of extracting genomic DNA from an egg or a 1st instar larva to species determination.
Subject(s)
Spodoptera , AnimalsABSTRACT
The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), spread rapidly in Africa and Asia recently, causing huge economic losses in crop production. Fall armyworm caterpillars were first detected in South Korea and Japan in June 2019. Here, the migration timing and path for FAW into the countries were estimated by a trajectory simulation approach implementing the insect's flight behavior. The result showed that FAWs found in both South Korea and Japan were estimated to have come from eastern China by crossing the Yellow Sea or the East China Sea in 10-36 h in three series of migrations. In the first series, FAW moths that arrived on Jeju Island during 22-24 May were estimated to be from Zhejiang, Anhui and Fujian Provinces after 1-2 nights' flights. In the second series, it was estimated that FAW moths landed in southern Korea and Kyushu region of Japan simultaneously or successively during 5-9 June, and these moths mostly came from Guangdong and Fujian Provinces. The FAW moths in the third series were estimated to have immigrated from Taiwan Province onto Okinawa Islands during 19-24 June. During these migrations, southwesterly low-level jets extending from eastern China to southern Korea and/or Japan were observed in the northwestern periphery of the western Pacific Subtropical High. These results, for the first time, suggested that the overseas FAW immigrants invading Korea and Japan came from eastern and southern China. This study is helpful for future monitoring, early warning and the source control of this pest in the two countries.
Subject(s)
Emigration and Immigration , Moths , Animals , China , Japan , Spodoptera , Zea maysABSTRACT
Ricania shantungensis Chou & Lu, 1977 (Hemiptera: Ricaniidae), is an invasive pest that attacks forest as well as agricultural trees. We sequenced the 15,358 bp long complete mitochondrial genome (mitogenome) of this species; it consists of a typical set of genes (13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes) and one major non-coding AT-rich region. The orientation and gene order of the R. shantungensis mitogenome are identical to that of the ancestral type found in majority of the insects. Bayesian inference (BI) phylogeny placed the R. shantungensis examined in our study, together with Ricania spp. in a group with the highest nodal support, forming the family Ricaniidae to which R. shantungensis belongs.
ABSTRACT
Current unmanned aircraft system (a.k.a. drone) technology is an effective tool for aerial survey of pests including weeds, plant diseases, and insects. This study was conducted to develop an aerial survey method that can locate cocoons of the oriental moth, Monema flavescens Walker, for precise and accurate detection of the cocoons in winter to prevent defoliation in the subsequent summer. We used a rotary-wing drone for an aerial survey of M. flavescens cocoons on 15 trees at 3-5 m above the tree canopy. We also conducted a conventional ground survey of M. flavescens cocoons on the same trees for two different conditions of cocoons: open (i.e., adult moths already emerged from cocoons) and closed (i.e., adult moths were not emerged yet). A validation census with destructive sampling was conducted to determine the precision and accuracy of the aerial and ground survey methods. The results of this study showed that from the aerial survey with the drone, images of open cocoons differed from those of closed cocoons. We found higher precision and accuracy and lower type I and II error rates for closed cocoons by the aerial survey with the drone than those by the ground survey. No significant relationships of the number of cocoons with tree height and diameter at breast height were found. This is the first study to demonstrate direct detection of insects with an aerial survey by using a drone.
Subject(s)
Moths , Remote Sensing Technology , Aircraft , Animals , TreesABSTRACT
The spotted lanternfly, Lycorma delicatula White, 1845 (Hemiptera: Fulgoridae), is an invasive pest that attacks forest as well as agricultural trees. We sequenced the 15,798-bp long complete mitochondrial genome (mitogenome) of this species; it consists of a typical set of genes (13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes) and one major non-coding A + T-rich region. The orientation and gene order of the L. delicatula mitogenome are identical to that of the ancestral type found in majority of the insects. Bayesian inference (BI) and maximum-likelihood (ML) phylogeny placed the L. delicatula examined in our study, together with other geographical samples of the species in a group with the highest nodal support, forming the subfamily Aphaeninae to which L. delicatula belongs.
ABSTRACT
We have determined a mitochondrial genome of Ricania speculum (Walker, 1851) collected in Jeollabuk-do, Republic of Korea. The circular mitogenome of R. speculum is 15,530 bp long which is shorter than that of the previous mitogenome of R. speculum by 199 bp. It includes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNAs. Intraspecific variation between two mitogenome of R. speculum was investigated: 171 SNPs and 18 INDELs were identified, presenting a high level of intraspecific variations on mitochondrial genome.
ABSTRACT
The genus Phanuromyia in the subfamily Telenominae (Hymenoptera: Scelionidae) consists of 60 described species, for which host records indicate they are egg parasitoids of lanternflies and planthoppers (Hemiptera: Auchenorrhyncha). In this study, we describe a new species of the genus, P. ricaniae sp. n., reared from the eggs of a planthopper, Ricania shantungensis Chou Lu (Hemiptera: Ricaniidae). This planthopper has been considered as a serious invasive pest in South Korean agriculture. Ricania shantungensis has a wide host range, including economically important crops such as apple, peach, and pear. Phanuromyia ricaniae therefore has the potential to be a biological control agent against ricaniid planthoppers.
Subject(s)
Hemiptera , Hymenoptera , Animals , Asia , Host SpecificityABSTRACT
The flatid planthopper, Metcalfa pruinosa (Hemiptera: Flatidae), which is an invasive species, is widespread in Korea. We sequenced a fragment of the COI from 536 individuals collected mainly in Korea and the European countries and combined these sequence data with the public data, totaling 830 individuals worldwide. The identification of one shared haplotype only between Korea and the USA, the presence of this haplotype only in the North-West region of Korea, and the highest haplotype diversity in this region suggested that the North-West region is another point of entry in addition to the South-East region, which is the presumed sole point of entry to Korea. Furthermore, it suggested that North-West entry involves the M. pruinosa originating from the USA. In an effort to find further variable regions in the mitochondrial genome, one region provided substantially increased variability compared to that of the fragment of COI. F ST estimation, PCoA, and BAPS analysis, using the concatenated sequences of COI and the newly detected variable region to infer the expansion pattern in Korea, indicates that the main highway, running obliquely between the North-West and South-East regions, appears to be responsible for the current population genetic structure of M. pruinosa in Korea, facilitating gene flow through this highway traffic.
ABSTRACT
One new leafhopper species, L. dangjinensis sp. nov. is described, and L. hebeiensis Cai, Liang Wang, 1992 is reported from Korea for the first time. Descriptions, photographs, illustrations and biological information of the new species are provided. A key to the Korean Limassolla species is also given. Limassolla macrobipunctata Hossain, Kwon, Suh Kwon, 2019 is synonymised with L. ishiharai Dworakowska, 1972.
Subject(s)
Hemiptera , Animals , Republic of KoreaABSTRACT
Taeniothrips changbaiensis sp. n. is described from specimens causing damage to the leaves of a species of Poaceae, Deyeuxia angustifolia, in Northeast China. This is one of three species of Taeniothrips with a banded fore wing, and one of only two species with an irregularly interrupted comb of microtrichia on abdominal tergite VIII. The number of setae is variable on the distal half of the fore wing first vein.
Subject(s)
Thysanoptera , Animals , China , Extremities , Plant Leaves , PoaceaeABSTRACT
Exorista japonica (Townsend, 1909), a dipteran tachinid fly, is an endoparasitoid of lepidopteran larvae as a potential biological agent. We have determined a 17,663 bp mitogenome of E. japonica which includes 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNAs, and a single large non-coding region of 2,773 bp. The base composition was AT-biased (81.4%). Phylogenetic trees present monophyly of Tachinidae and Exoristinae, where two Exorista species are clustered in single clade, Exoristini. The E. japonica mitogenome will be a good resource for understanding phylogenetic relationship among species of Tachinidae presenting morphological and ecological complexities.
ABSTRACT
The fall armyworm, Spodoptera frugiperda, is a serious pest in large numbers on more than 350 plant species in the world. We have determined a 15,388 bp mitogenome of S. frugiperda which includes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNAs. The base composition was AT-biased (81.3%). Phylogenetic trees present that Korean S. frugiperda placed in basal position of S. frugiperda clade. S. frugiperda mitochondrial genome can be used for understanding recent active migration of S. frugiperda.
ABSTRACT
The Asopinae genus Stilbotes Stål, 1871 from Philippines is reviewed taxonomically. A new species Stilbotes goulae sp. nov. is described based on female specimens. Stilbotes semperi Stål 1871 is redescribed in detail. A diagnosis, key and distributional records for the genus and the species are also provided.
Subject(s)
Hemiptera , Heteroptera , Animals , Female , PhilippinesABSTRACT
A nationwide survey was performed to investigate the current incidence of viral diseases in Korean sweet potatoes for germplasm and growing fields from 2011 to 2014. A total of 83.8% of the germplasm in Korea was infected with viruses in 2011. Commercial cultivars that were used to supply growing fields were infected at a rate of 62.1% in 2012. Among surveyed viruses, the incidence of five Potyvirus species that infect sweet potato decreased between 2012 and 2013, and then increased again in 2014. Representatively, the incidence of Sweet potato feathery mottle virus (SPFMV) was 87.0% in 2012, 20.7% in 2013 and then increased to 35.3% in 2014. Unlike RNA viruses, DNA viruses were shown to decrease continuously. The incidence of Sweet potato leaf curl virus (SPLCV) was 5.5% in 2003, 59.5% in 2011, and 47.4% in 2012. It then decreased continuously year by year to 33.2% in 2013, and then 25.6% in 2014. While the infection rate of each virus species showed a tendency to decline, the virus infection status was more variable in 2013 and 2014. Nevertheless, the high rate of single infections and mixed infection combinations were more variable than the survey results from 2012. As shown in the results from 2013, the most prevalent virus infection was a single infection at 27.6%, with the highest rate of infection belonging to sweet potato symptomless virus-1 (SPSMV-1) (12.9%). Compared to 2013, infection combinations were more varied in 2014, with a total of 122 kinds of mixed infection.
ABSTRACT
Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) has caused substantial agricultural damage since its recent introduction to the Republic of Korea; however, the source of this introduction is still unclear. To examine the genetic divergence and phylogenetic relationships among several populations of M. pruinosa from Korea and foreign countries, 251 COI sequences from 251 samples collected from Korea, France, Italy, Spain, Slovenia, and the United States were newly analyzed, together with seven published COI sequences from Canada. In total, 19 haplotypes were detected from the 258 COI sequences, and three haplotypes, H1, H3, and H9, were detected from samples in Korea. The MJ network and Bayesian inference revealed that the three haplotypes of Korea were closely connected with samples of Italy, Spain, Slovenia, France, and the United States. Our study revealed the possibility of multiple invasions of M. pruinosa from Europe and/or North America into Korea.
Subject(s)
Genetic Variation , Haplotypes , Hemiptera/genetics , Animals , Electron Transport Complex IV/genetics , Insect Proteins/genetics , Introduced Species , Phylogeny , Republic of Korea , Sequence Analysis, DNAABSTRACT
BACKGROUND: The behaviour of insect vectors can be altered by the acquisition of plant viruses. Bemisia tabaci, which is the vector of Tomato yellow leaf curl virus (TYLCV), causes damage to susceptible tomato cultivars. Here, the frequencies of several behavioural characteristics related to probing and feeding that are exhibited by non-viruliferous (NV) and TYLCV-viruliferous (V) adult B. tabaci were compared using a sandwich-type parafilm cage. RESULTS: The frequencies of behaviours such as wing flapping, leg movement, body shaking and body position change while settling and feeding on plant leaves were higher in V than in NV whiteflies. Evaluation of probing frequencies by measuring the number and size of holes punctured in parafilm by whiteflies revealed that most holes had a diameter of 7.5-26.7 µm, which is within the range of proboscis diameters of whiteflies. There were more small-sized holes than medium- and large-sized holes. Male whiteflies produced more small-sized holes, but females more mid-sized holes. V whiteflies showed increased hole numbers but decreased feeding duration relative to NV whiteflies. CONCLUSION: Adult B. tabaci showed higher frequencies of probing and feeding behaviours when infected with TYLCV. These manipulations of feeding behaviours of insect vectors may result in increased transmission of plant virus.
Subject(s)
Begomovirus/pathogenicity , Feeding Behavior/physiology , Hemiptera/virology , Insect Vectors/virology , Animals , Female , Hemiptera/physiology , Insect Vectors/physiology , Solanum lycopersicum , Male , Plant Diseases/virology , Plant Leaves , Sex FactorsABSTRACT
Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important insect pests in the world. In the present study, the taxonomic status of B. tabaci and the number of species composing the B. tabaci complex were determined based on 1059 COI sequences of B. tabaci and 509 COI sequences of 153 hemipteran species. The genetic divergence within B. tabaci was conspicuously higher (on average, 11.1%) than interspecific genetic divergence within the respective genera of the 153 species (on average, 6.5%). This result indicates that B. tabaci is composed of multiple species that may belong to different genera or subfamilies. A phylogenetic tree constructed based on 212 COI sequences without duplications revealed that the B. tabaci complex is composed of a total of 31 putative species, including a new species, JpL. However, genetic divergence within six species (Asia II 1, Asia II 7, Australia, Mediterranean, New World, and Sub Saharan Africa 1) was higher than 3.5%, which has been used as a threshold of species boundaries within the B. tabaci complex. These results suggest that it is necessary to increase the threshold for species boundaries up to 4% to distinguish the constituent species in the B. tabaci complex.
