The two-spotted spider mite, Tetranychus urticae Koch, is one of the economically important agricultural pests globally, as it attacks a wide range of vegetable and horticultural crops. In this study, we evaluated spatial repellent and oviposition deterrent activities of T.urticae in response to fifteen compounds derived from ester-containing natural products. To evaluate the tests, we used bridge two-choice test and host two-choice test in laboratory conditions. Among the eight compounds showed spatial repellent and oviposition deterrent activities against T. urticae at the 20 mg dose and some compounds had the activities at lower dose. We also conducted two-choice test with a blend and single compounds to determine which showed stronger spatial repellent and oviposition deterrent activities. In host two-choice test, we evaluate repellence between distance of compounds. This study concluded that series compounds from ester-containing natural products have the potential to be used managing T. urticae in the field.

Tropilaelaps mercedesae Anderson and Morgan, 2007 (Acari: Laelapidae) is a serious ectoparasite of the brood of several honey bee species. Among the four recognized species of Tropilaelaps, Korean population was renamed as T. mercedesae from T. clareae on the basis of morphological evidences and genetic data. In this study, we report the complete mitochondrial genome (mitogenome) sequence of T. mercedesae. The 15,119-bp long mitogenome has an identical gene arrangement to that of Chinese sample reported previously. Comparison of two geographic samples showed COII, ND5, ND4, ND6, CytB, and ND1 to have higher number of variable sites than COI, which is often used for population-level study, suggesting these genes to have potential usefulness for population genetic study. The mitogenome sequence of T. mercedesae from Korea could be useful for species identification for geographic samples, trace of the origin of local populations, and illustration of evolutionary distinction among Tropilaelaps species either using part of or whole genome.

Scrub typhus is a zoonotic bacterial disease caused by Orientia tsutsugamushi (Rickettsiales: Rickettsiaceae) and trombiculid mite larvae, also known as chigger, are known vector. Until recently, O. tsutsugamushi is the only species of the genus. However, two new species Candidatus O. chuto and Candidatus O. chiloensis that causes scrub typhus were reported recently in the Middle East, southern Chile, and Africa. In addition, Orientia spp. bacteria detected from field collected free-living Eutrombicula chigger mites in the United States. Despite these trends, research on new species is insufficient in the Republic of Korea. Therefore, we focused on finding the presence of novel species or strains from chiggers. Specimen chiggers harvested from rodents collected in 16 regions in October 2022 collaborating with the Regional Center for Vector Surveillance against Climate Change were selected. A total of 1,249 specimen belonging 4 genera and 14 species were identified by using a fluorescence microscope and 266 pools were produced by pooling up to 10 individuals per species chiggers. To detect Orientia spp., we screened by using a real-time PCR targeting the 16S rRNA gene. Overall minimum infection rate was 0.56% (7 pools/1,249 tested specimen). After screening, conventional nested-PCR for targeting 47-kDa htrA gene was conducted to obtain sequences, and four of the positive pools were amplified. Through phylogenetic analysis, three pools were clustered with O. tsutsugamushi Gilliam and UT221 strain, and the other pool was formed a clade that was distinct from O. tsutsugamushi. These results suggest that novel species of Orientia may exist in the Republic of Korea.

본 연구를 통해 국내에 분포하는 중기문응애류 중 파리응애과의 Holostaspella crenulata Krantz, 1967 (톱니무늬파리응애, 신칭) 와 화살응애 과의 Lasioseius floridensis Berlese, 1916 (가슴선화살응애, 신칭) 를 처음으로 확인하고, 각 종에 대한 분류학적 진단과 분포정보, 성충의 현미경사 진과 도판을 제시하였다.

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important agricultural pests. Therefore, we screened fifteen compounds from natural products for their spatial repellent and oviposition deterrent activities against T. urticae in the laboratory by using two-choice and no-choice tests. In the bridge two-choice test, nine compounds showed the spatial repellent effects on T. urticae at 20 mg dose, resulting in reduced numbers of eggs. Among the nine compounds, at 2 mg dose, two compounds were selected as having more spatial repellent activity than the others. The two compounds also showed spatial repellent and oviposition deterrent effects in the two-choice test from hosts. In the no-choice test from a host, the spatial repellent effects of the two compounds to T. urticae were significantly stronger than that of controls. These results suggest that the findings can be used as potential agents for the prevention and population control of T. urticae in the field.

Orientia tsutsugamushi 에 의해 발생하는 쯔쯔가무시증은 제3급 법정감염병으로 관리되고 있으며, 설치류에 기생한 털진드기 유충에 의해 주로 매개되는 것으로 알려져 있다. 원인균인 O. tsutsugamushi 는 Gilliam, Karp, Kato와 같은 표준 혈청형 외에도 유행하는 국가에 따라 30종 이상의 다양한 혈청형이 존재하는 것으로 알려져 있어, 각 지역에 대한 지속적인 조사가 필요하다. 우리 연구진은 야생 설치류에 기생하는 털진드기의 O. tsutsugamushi 감염 여부를 확인하기 위해 충남 예산에서 2018년부터 2023년까지 3-4월, 10-11월에 걸쳐 수행하였 다. 총 142마리의 설치류가 포획되었으며, Hanging method로 설치류에서 분리된 털진드기는 총 18,347마리였다. 수거된 털진드기의 샘플 중 1/2은 질병관리청으로 이관하였으며, 나머지 절반을 이용하여 O. tsutsugamushi 감염 여부를 확인한 결과 2018년 5건, 2019년 2건, 2020년 0건, 2021년 9건, 2022년 0건, 2023년 36건이 확인되었으며, 혈청형 분석 결과 Je-cheon 28건, Young-worl 3건, Boryoung 9건, Koto Akita 1건, Gilliam 2건, Karp 9건으로 확인되었 다. 이번 연구를 통해 예산 지역 내 다양한 O. tsutsugamushi 혈청형이 있음을 확인하였으며, 이러한 결과는 향후 지역에 따른 혈청형 차이가 반영된 공중보건학적 전략 수립을 위한 기초자료로 활용될 수 있을 것으로 사료된다.

Beetles are one of the most effective transportation for phoretic chelicerata. They use various methods to attach themselves to their hosts, such as developing ventral sucker plates, grasping with their claws and chelicerae, or hiding beneath the elytra. Recently, we discovered new species of two genera: Antennoseius (Mesostigmata: Blattisociidae) and Gaeolaelaps (Mesostigmata: Laelapidae) which are hiding under the elytra of Carabidae hosts. In this study, digital images of the beetles, and mites, along with brief diagnostic information and line-drawing plates will be provided.

본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 제초제 살포 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)에 따른 귤 응애의 개체군 동태를 구명하고자 수행되었다. 두 가지 기본적인 가설로 1) 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응 애의 발생을 감소시키는 요인으로 작용하며, 2) 합성피레스로이드계는 천적을 제거하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 관측 된 천적 개체군(주로 이리응애류와 마름응애류)의 발생은 가정에 근거한 기대치와 크게 다르지 않았다. 2011년의 경우 NW+NP 처리구와 W+NP 처리구에서 차이가 있었으나, 2012년 실험에서는 기대치와 관측치가 거의 일치하였다. 전체적으로 약제효과가 뚜렷하게 나타나서 합성 피레스로이드계 살포시 천적이 유의하게 감소하였다. 잡초효과는 엇갈리는 결과를 보였는데, 봄-유래 여름 개체군 대비 가을 개체군의 증가 등을 고려할 때 초생재배를 하는 경우 천적의 발생이 증가하였다. 다만, 합성피레스로이드계 살포구에서 귤응애가 감소하는 비이상적인 결과는 귤응 애의 합성피레스로이드계에 대한 강한 기피성을 전제로 해석할 수 있었다.