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        검색결과 68

        36.
        2019.04 구독 인증기관·개인회원 무료
        Ambrosia artemisiifolia is native in North America and an invasive alien species in East Asia and Europe. This plant causes economic losses such as reducing agricultural production and producing severe allergenic pollen. Recently, there was an effort to control this alien plant chemically and mechanically in South Korea, but they are neither sustainable nor environmentally-friendly control strategies. Epiblema sugii Kawabe 1976 (Lepidoptera: Tortricidae) is known as a potential biological control agent of A. artemisiifolia. In order to control this species using a biological control method, we investigated overwintering structures and spatial distributions of E. sugii in A. artemisiifolia colony as an initial step.
        37.
        2018.10 구독 인증기관·개인회원 무료
        Although understanding dispersal ecology is important of Haemaphysalis longiconirs (Acari: Ixodidae) to control severe fever with thrombocytopenia syndrome, the small size of H. longicornis makes it challenging to study their behaviors. We examined the potential of fluorescent marking system (FMS) paired with an ultraviolet laser, an effective insect detection method, in tracking of H. longicornis. When we assessed potential effects of FMS on the survivorship and behavioral parameters including horizontal movement, vertical climbing height, and response to CO₂ of all development stages (larva, nymph, and adult) of H. longicornis, it did not induce any adverse effects on the hard ticks. Furthermore, we measured the detectable distance and detection rate of larvae, nymphs and adults to evaluate the detection efficacy of FMS. Using an ultraviolet laser, operators could detect the hard ticks from a distance ranging from 12 m (larva) to 29 m (adult). When the detection rate was measured in a grassland both during day and night, it was higher at night compared to day and increased with the body size. The detection rate was over 90% for all stages of the hard ticks at night, whereas larvae and nymphs showed that of 23% and 34% respectively during the day. However, the detection rate of adults was higher compared to other development stages regardless of time of experiment. Our results indicate that FMS can serve as a promising tool to track the hard ticks by providing reliable detection efficacy with no adverse effects on the marked individuals.
        38.
        2018.10 구독 인증기관·개인회원 무료
        In general, hemipteran insects transmit either obligate or facultative symbionts to their offspring using various transmission mechanisms. Riptortus pedestris (Hemiptera: Alydidae) also have facultative symbiosis with Burkholderia sp. which is acquired from the soil every generation especially during 2nd instar nymphal period. This environmental symbiont transmission makes R. pedestris face a great risk of missing their symbionts, however, previous studies showed that they have intimate associations with their symbionts. Therefore, we suspected that R. pedestris 2nd instar nymphs may have a preference toward Burkholderia sp. to achieve an efficient symbiont acquisition during the limited time of window. In order to identify the preference of 2nd instar nymph, we first conducted dual-choice experiments varying with the number of 2nd instar nymphs (a nymph and 100 nymphs) in plastic cages. Furthermore, Y-tube olfactometer experiments varying with the presence of soil as medium of Burkholderia sp. were performed to determine if the insects respond to bacterial volatile induced from the symbiont. Based on our results, we observed that R. pedestris 2nd instar nymphs may not show any specific behavioral preference or response to chemical volatile from Burkholderia sp. in laboratory conditions (P >0.24). Therefore, we will further conduct a dual-choice experiment in a semi-field condition to investigate if such patterns can be detected in a larger arena simulating a more natural environment.
        39.
        2018.04 구독 인증기관·개인회원 무료
        Modern technique development provides a new opportunity to expand entomological researches. Aerial insect sampling has been conducted with fixed-wing unmanned aerial vehicles (UAVs). With improved maneuverability, rotary-wing UAVs can serve as more convenient and feasible tools with lower cost. A rotary-wing UAV with remotely controlled insect nets was developed to collect insects at designated altitudes above the rice field (ca. 80 × 240 meter (width × length)) in Boryeong, South Korea. From 21 flights in June, July, and August 2017, 235, 7, 6, and 3 insects were caught at 5, 10, 50, and 100 meters above the rice field, respectively. The collected insects were identified to family level. Diptera (Phoridae and Chironomidae), Hemiptera (Aphididae and Delphacidae), and Thysanoptera were found from the sample, some of which may contain possible insect pests on rice. Therefore, UAVs have potential as an alternative aerial insect sampling method.
        40.
        2018.04 구독 인증기관·개인회원 무료
        Both a fluorescent marking system (FMS) and a portable harmonic radar system (PHRS) are effective insect tracking methods. Prior to comparing their efficacies, we tested the viability of FMS in detection of an agricultural pest, Riptortus pedestris (Hemiptera: Alydidae); previous studies showed the harmlessness of PHRS on R. pedestris and its detection distance. Fluorescent marking allowed the detection of marked R. pedestris from > 25 m, when illuminated with a laser in the dark, while affecting only the vertical walking distance of the insect. Then, we assessed the efficacy of the FMS and PHRS as well as combining both methods (BOTH) in detection of R. pedestris in a grass field and a bean field during day and night. PHRS and BOTH showed higher detection rates than FMS in all settings, except for in the bean field at night. Also, although BOTH did not enhance total detection time, it facilitated the retrieval of the sample at night compared to only using PHRS.
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