Riptortus pedestris (F.) (Hemiptera: Alydidae) attacks several leguminous crops and its reproductive success is found to be affected by the leguminous host types. Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) is an egg parasitoid of R. pedestris and its quality attributes depend on the host egg quality. We, thus, investigated the performance of O. nezarae on eggs of R. pedestris fed on different leguminous seeds. Eggs collected from R. pedestris female adults obtained from rearing on one of the four hosts such as soybean, adzuki bean, mung bean, and cowpea seeds were exposed as a batch (n=15) to a single 4 to 5 day-old mated female O. nezarae. The eggs exposed were collected after 24 h. Number of parasitized eggs, sex ratio, development times, and adult emergence were recorded. The maximum number of eggs parasitized by O. nezarae were the eggs of mung bean fed R. pedestris. Eggs produced from the adzuki bean fed bugs had the lowest parasitization. There was no difference recorded in the developmental time of parasitoids emerged from the eggs of R. pedestris fed on different legumes. Proportion of male O. nezarae was highest on the eggs of cowpea seed fed adult bugs (26%); the lowest of that was found on the eggs of mung bean fed bugs (22.4%). Ooencyrtus nezarae can successfully parasitize eggs of R. pedestris regardless of hosts food sources. However, eggs of mung bean fed R. pedestris, among the tested legumes, were found to be of the best quality for reproductive success of O. nezarae.

톱다리개미허리노린재[Riptortus pedestris (Fabricius) (Hemiptera: Alydidae)]는 콩에서 중요한 난방제 해충이다. 톱다리개미허리노린재와 두 종의 알기생벌의 계절적 발생 패턴을 기주 식물과 연관하여 고찰하였다. 또한 천적 상호간의 상대적 발생 패턴의 차이와 이유를 분석하고 톱다리개미허리노린재의 기주 식물에 대한 적합도 검증 결과를 바탕으로 톱다리개미허리노린재의 관리 전략을 제시하였다. 톱다리개미허리노린재의 효과적인 관리를 위해서 저항성품종의 사용, 과수의 경우 주변 작물에서 콩을 배제하는 것, 기주알 공급을 통한 보존적 생물적 방제, 살충제 사용 시기의 조절 등이 고려되어야 한다.

This study was conducted to determine the effect of six different leguminous seeds a) cowpea, b) white kidney bean c) soybean (Cheongja) d) soybean (Daepung) e) mung bean and f) azuki bean on the nymphal development, mortality, adult longevity, fecundity and hatchability of Riptortus pedestris (F.) (Hemiptera: Alydidae). Total developmental time ranged from 18 to 25 days; R. pedestris fed on white kidney bean took the longest time. There was no difference in mortality among the bugs fed on the legumes except those fed on white kidney bean which had the highest mortality (94%). Also, adult bugs fed on white kidney bean showed the shortest longevity. Total number of eggs laid by adult female and the hatchability of the eggs were highest from the bugs fed on cowpea. Higher reproductive success of R. pedestris fed on cowpea suggests that cowpea could be very suitable legume for the bug and it can be used as a trap crop against the bean bug.

Several pentatomids and an alydid are reported inflicting losses in several host plants ranging from leguminous crops to fruit orchards in Korea. Understanding their visual preference would help develop mass trapping or efficient monitoring device. Visual preference of the major pentatomids and an alydid bugs to different colors and light emitting diodes (LED) of different wavelengths were observed. Adults of pentatomid such as Halyomorpha halys Stål, Plautia Stali Scott, and Nezara sp., and an alydid Riptortus pedestris (F.) were exposed to seven different colors (black, yellow, green, blue, white, cream, orange) in a multiple choice tests. Also, adult and second instar nymphs of the bugs were released inside a hexagonal LED boxes consisting of LED lamps of six different wavelengths (375 to 630 nm). Most of the pentatomids showed highest preference to blue color followed by yellow and 530 nm LED. However, R. pedestris showed higher preference to the yellow color followed by blue and black. Second instar nymphs of all the tested species also showed higher preference to 530 nm. Their color and LED lamp preference would help in development of mass trapping device.

톱다리개미허리노린재(Riptortus pedestris [Fabricius] [Hemiptera: Alydidae])는 콩에서 특히 중요한 해충이다. 효과적 관리 전략 수립을 위해 톱다리개미허리노린재의 계절적 발생 패턴과 기주 식물의 먹이 적합성, 천적 기생벌들의 발생 소장과 상호관계에 대해 연구한 결과를 요약하였다. 톱다리개미허리노린재는 보리, 참께, 콩 등이 복합적으로 재배되는 전작지에서 모두 채집되었으나 콩에서 가장 밀도가 높았다. 콩 외의 작물은 실내 먹이실험에서 성충으로 발육하지 못하여 콩이 가장 주요한 먹이원임을 알 수 있었다. 한편 노린재검정알벌(Gryon japonicum [Ashmead] [Hymenoptera: Scelionidae])과 노린재깡충좀벌(Ooencyrtus nezarae Ishii [Hymenoptera: Encyrtidae])이 톱다리개미허리노린재의 주요 천적이며, 노린재검정알벌은 봄에서 초여름에 노린재깡충좀벌은 여름과 가을에 우점을 보인다. 이는 두 종이 경쟁적 배제를 통한 한 종의 멸종이 일어나지 않게 기주 자원을 시간적으로 분할한 결과로 보인다. 이러한 노린재와 기주식물(bottom-up) 그리고 천적(top-down)과의 상호관계의 이해를 통한 해충관리전략에 대해 고찰하였다.

Ooencyrtus nezarae Ishii and Gryon japonicum (Ashmead), egg parasitoids of Riptortus pedestris (Fabricius), coexist despite direct competition for host eggs. As asymmetrical pattern of seasonal occurrence, i.e., more G. japonicum during spring-summer and more O. nezarae during summer-fall, has been reported, host resource partitioning may occur in temporal scales. To test this hypothesis, we demonstrated the interspecific competition between the two species by measuring parasitism in nine combinations of host densities and exposure times. To reflect gregarious-solitary dichotomy, three O. nezarae and one G. japonicum mated females were used in each experiment. O. nezarae was better competitor when exposure time was longer than 1 day irrespective of host densities. Parasitism rate and progeny emergence of O. nezarae was 1.6-2.8 and 4.7-7.3 times higher than G. japonicum. O. nezarae has higher potential rate of increase than G. japonicum due to gregariousness, and be more successful in larval competition inside multiparasitized host egg as it acts as a facultative hyperparasitoid. Although G. japonicum was more effective in host finding (as they showed relatively higher per capita parasitism and progeny emergence), their progeny suffered high mortality from the larval competition with O. nezarae. These results may explain the asymmetrical occurrence pattern in the field.

톱다리개미허리노린재(Riptortus pedestris [Fabricius] [Hemiptera: Alydidae])는 콩 포장에서 주요 해충이며, 기생천적으로는 노린재깡충좀벌(Ooencyrtus nezarae Ishii [Hymenoptera: Encyrtidae])과 노린재검정알벌(Gryon japonicum (Ashmead) [Hymenoptera: Scelionidae])이 있다. 저온 저장시켜 불활성화된 노린재 알을 집합페로몬 트랩에 부착하면 기생률이 증가한다고 보고되었다. 본 연구에서는 위 기술을 이용하여 불활성화된 노린재 알의 밀도에 따른 기생률 향상 효과를 조사하였다. 경북 의성군 옥산면에 위치한 콩 포장(100×140m)을 12개의 시험구로 나누고 집합페로몬 트랩을 각각 4개씩 설치하였다. 시험구에는 3개의 처리구와 1개의 대조구를 두었으며, 처리구에는 1, 2, 4개의 집합페로몬 트랩에 트랩당 60개의 알을 부착하였다. 그 결과 처리구에서 노린재깡충좀벌에 의한 기생률은 23~51%이었고, 대조구에서는 25%이었다. 노린재검정알벌의 경우 처리구에서 19~42%의 기생률을 보여 주었고, 대조구의 기생률은 22%이었다. 240개의 알을 부착한 시험구에서 노린재깡충좀벌과 노린재검정알벌에 의한 기생률이 최대 51, 42%이었고, 노린재 알을 설치하지 않은 대조구의 기생률 보다 각각 2.1, 1.9배가 높았지만 톱다리개허리노린재의 밀도는 차이가 없었다.

Aggregation pheromone of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has kairomonal effect on its egg parasitoids. Thus, inclusion of non-viable host eggs of R. pedestris to aggregation pheromone trap was suggested to propagate parasitoids attracted in the trap. In this study, spatial and temporal distribution of egg parasitoids were investigated in sesame fields in Songcheon, Andong where aggregation pheromone traps were installed with non-viable host eggs. Parasitism changes were assessed after collecting non-viable host eggs released at distances of 8, 16, 24, and 32 m from the trap. Higher egg parasitism and adult emergence was found up to 16 m from the point of release. Parasitism increased over time, but decreased with distance. For the comparison of change in temporal parasitism, traps were installed without host eggs in another sesame field. Parasitism rate in sesame field without host eggs increased by 13%, whereas, in the field with host eggs, the parasitism increased up to 44%. These findings suggest that host eggs attached to the pheromone traps help the parasitoids propagate and disperse.

톱다리개미허리노린재의 집합페로몬은 수컷에 의해 분비되며 같은 종의 성충과 약충을 유인하는 것으로 알려져 있다. 현재 합성된 집합페로몬을 이용한 유인트랩이 널리 이용되고 있다. 본 연구에서는 합성된 집합페르몬에 대한 톱다리개미허리노린재 성충과 약충의 반응을 먹이 섭식 조건을 달리하여 Y자 후각계(Y-tube olfactometer)를 이용하여 조사하였다. Y자 후각계 끝의 공기와 페로몬이 혼합되는 지점에서 교미경험이 없고 수분만 공급받은 성충의 최초 반응률은 수컷에서 84%, 암컷에서 90%이었다. 그리고 반응한 암컷과 수컷의 69%가 Y자 후각계의 집합페로몬 쪽으로 이동하였다. 제2령 약충에서는 수분과 설탕물을 공급받은 경우 최초 반응률은 각각 60과 56%이었고 그 중 각각 63과 64%가 집합페로몬 쪽을 선택하였다. 다만 콩을 먹이로 충분히 공급받은 제2령 약충은 최초 반응률이 34%로 낮았고 집합페로몬 쪽으로 유인된 비율도 31%로 낮았다. 따라서 톱다리개미허리노린재 약충이 먹이를 섭식한 후에는 집합페로몬에 적게 유인되는 것을 알 수 있다.

Periodical release of non-viable refrigerated eggs of Riptortus pedestris (Fabricius) has been found to enhance field parasitism level in soybean fields. However, optimum refrigeration conditions required for the eggs in order to preserve its quality to ensure effective level of parasitism for a longer period has been rarely reported. We assessed optimum environment condition for refrigeration of the eggs using three different temperatures (2, 6, and 10℃) and relative humidities (RH) (high, medium and low). Eggs of R. pedestris were refrigerated at nine combinations of temperature and relative humidity for 30 consecutive days. Those eggs were taken out and after 8 days, mated female Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) were individually exposed to the eggs, and their development, emergence, and sex ratio were examined. Number of eggs parasitized was highest (5.9) on eggs stored at 6℃ and high RH. Significantly higher male proportion was recorded in the eggs stored at 10℃. However, RH had no effect on the sex ratio. For both male and female, development time was the least on host eggs stored at 2℃ and high RH. Adult emergence was recorded highest from the eggs stored at 2℃ followed by 6℃ and at high RH. In conclusion, eggs refrigerated below 6℃ at high RH condition maintained better quality of R. pedestris eggs for the parasitization by O. nezarae.

From our previous studies in a farm in Songcheon, Andong where a series of crops was cultivated in 2008 and 2009, occurrence patterns of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) and its egg parasitism by Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae) were reported. With an objective to verify the trend of the occurrence pattern, a year long monitoring of R. pedestris and its egg parasitism was continued in 2010 in the same location where barley, sesame, and soybean were cultivated in series. We placed four aggregation pheromone traps added with 50 refrigerated eggs of R. pedestris each along the perimeter of the field from 11 April to 31 October. Weekly occurrence patterns of R. pedestris and its parasitism in 2010 were generally similar to the patterns of previous years. Riptortus pedestris population first appeared in the last week of April, peaked after the third week of August, and declined in October. Parasitism by G. japonicum was recorded up to 64% in July, 2010 which was much higher than previous years. This study verifies that G. japonicum is the first colonizer that appears as early as May and remains active until September. Ooencyrtus nezarae, however, starts to occur late from the last week of August and exist in the field until October.

Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae) are major egg parasitoids of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), a mobile pest on several crops in Korea and Japan. We compared the sensitivity of the two parasitoids to different temperature and relative humidity (RH) conditions to understand their phenological relations. Less than 6 hours old naïve female adult O. nezarae and G. japonicum were individually kept in 50 ml tubes without food and water sources. The tubes were placed in three humidity conditions (50-55, 70-75, and 90-95% RH) in desiccators. These desiccators were then maintained at 20, 25, and 30°C. In each temperature and RH combination 75-76 individuals were assessed for the mortality every 8 hours. G. japonicum was found to survive longer (37-116 hours) in all the temperature and RH combinations than O. nezarae (31-103 hours). Both the two parasitoids survived better in higher RH in all temperatures. The reduced sensitivity to lower humidity by G. japonicum compared to O. nezarae may explain the earlier occurrence of G. japonicum in the spring. The relations with seasonal occurrence of the two parasitoids were discussed.

Chrysanthemum flower model trap developed by modifying an artificial yellow chrysanthemum flower was reported to be more attractive to flower thrips than a commercial yellow sticky trap. The installation of the traps (20 traps per 50 m2 plot), especially, reduced the seasonal populations of Frankliniella intonsa Trybom (Thysanoptera: Thripidae) on strawberry flowers in greenhouse by 82% compared to the untreated control. In this study, we tested if the installation of the flower model traps can reduce thrips population on a red pepper field located in Seokdong, Andong. The pepper field was treated two times with pesticides during the period of experiment. The traps were installed in plant canopy at different densities (0, 5, 10, 20 traps) in 20 plots (3×5 m2 each) using a completely randomized design. Population of thrips was examined on the collected pepper flowers from 1 July to 29 July in 2009. Thrips found on the flowers were all F. intonsa. Significance effect of treatment and sampling date was found from repeated-measure analysis of variance. The highest density of traps significantly reduced female and male F. intonsa population by 60% and 46% compared to the control, respectively. However, no difference in immature population was found among the treatments. These results indicate flower model trap can be an additional tool for the management of flower thrips on field red pepper.

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) causes losses in several crops in Korea. Release of non-viable refrigerated eggs of R. pedestris is known to enhance natural parasitism by Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae) in soybean fields. In this study, we conducted an experiment of cage-exclusion design to verify the former results in more manipulative approach in a soybean field. Agakong field (45×26 m2) located at Songcheon, Andong was divided into 15 plots (10×6 m2) with each experimental arena of 3×2 m2 in the center. There were three treatments: (1) release of refrigerated eggs of R. pedestris, (2) release of refrigerated eggs with one time spray of thiamethoxam, and (3) untreated control. A fine mesh cloth with iron poles was used to encircle the arenas. Refrigerated eggs of R. pedestris were released (100/arena) twice before sampling. One-day old eggs of R. pedestris were released (60/arena) in all the experimental arenas at an interval of 6 days, and 30 eggs from each were collected to record parasitism. We found no significant difference in the eggs and nymphs population of R. pedestris among the treatments. However, adult density was significantly reduced in the treated plots during final two sampling days compared to the control. We found significantly higher parasitism by G. japonicum on the eggs collected from treated plots (9-25%) compared to the control plots (1-9%). It is verified that releasing non-viable eggs of R. pedestris help to enhance natural parasitism in soybean field.

Ooencyrtus nezarae Ishii (Hemiptera: Encyrtidae) and Gryon japonicum Ashmead (Hymenoptera: Scelionidae) are two important egg parasitoids of soybean stink bug Riptortus clavatus, one of the most serious pests in Korea. On the verge of increasing severity of R. clavatus damage in other crops, now it is important to know temporal distribution of R. clavatus and its parasitoids throughout cultivation season of various crops. Seasonal occurrence of R. clavatus and its egg parasitoids is well studied in soybean. However, occurrence of spring populations has not been fully investigated. Therefore we placed pheromone trap with refrigerated eggs in barley and early soybean fields to record occurrence of both R. clavatus and its’ egg parasitism rate in 2008. Number of R. clavatus attracted in the trap was recorded every week, and host eggs collected same time were brought into laboratory for investigation of parasitism. R. clavatus was found to exist in barley on the first day of trap installation, i.e., May 11th. Number of R. clavatus reached highest level after mid July. Only G. japonicum emerged from the eggs collected from barley field whereas O. nezarae was dominant species emerged from the host eggs collected from soybean field. We found that not only R. clavatus infestation but parasitoid occurrence begins in early spring barley field.

아가, 청자, 대원의 세 가지 콩 품종이 톱다리개미허리노린재의 발육과 생식이 미치는 영향을 실내에서 비교하였고, 또한 이 세 가지 품종 간에 야외 발생소장을 비교하였다. 실내 실험에서 약충의 발육기간은 아가, 청자, 대원콩에서 각각 평균 14.5, 14.0, 14.6일이였고, 약충의 사망률은 각각 40.0, 51.3, 55.7%였다. 발육기간에서는 통계적 차이가 없었지만, 사망률에서는 아가콩에서 유의하게 다른 두 품종보다 낮았다. 성충의 생식능력으로 7일 동안 암컷이 산란한 알의 총 개수의 평균은 각각 67.8, 68.0, 67.7개였으며 통계적 차이는 없었다. 야외조사는 안동시 풍산면 소재 친환경 인증 포장에서 아가, 청자, 대원을 각각 3반복의 라틴방각법으로 배치하여 재배하였다. 7월 13일부터 10일 간격으로 8회 동안 알, 약충, 성충의 수를 각 처리구에서 임의로 30주를 조사하였다. 조사기간 전체 동안 발생 수는 알의 개수가 아가, 청자, 대원콩에서 각각 평균 18.3, 23.0, 23.7개, 약충은 각각 평균 8.0, 11.3, 17.3마리, 성충은 각각 평균 7.3, 21.3, 15.7마리가 조사되었다. 톱다리개미허리노린재의 알과 약충에서는 통계적인 차이가 없었지만, 성충은 아가에서 가장 적게 발생하였다. 이상의 결과로 새로운 품종인 아가콩은 다른 두 품종에 비해 톱다리개미허리노린재의 유충 생존율을 높였지만 성충의 발생은 다른 두 품종에 비해 적음을 알 수 있었다.

Chrysanthemum flower model trap (CFMT) developed to attract the flower thrips was evaluated for its optimal trap density that is required to manage the population of flower thrips in a strawberry greenhouse. CFMTs were installed in different rates per unit area (10m×5m), i.e., control (no trap), low (5 traps), medium (10 traps), and high (20 traps), in three different strawberry greenhouses at Namhoo, Andong. From each plot, 10 flowers were sampled every week from 16 May 2008 to 6 June 2008. Five traps were also randomly collected from each plot every week to record the number of flower thrips trapped. The seasonal number of both female and male thrips collected in the flowers was significantly lower in the plots with high density of traps compared to the control. In the plot with medium level of traps, less seasonal number of male F. intonsa were found in the strawberry flowers compared to the plot with low level of traps or control. When the numbers of thrips in the flowers were plotted against the numbers of thrips trapped in the CFMTs, significant correlation was found in female thrips only. However, there was no significant difference in seasonal number of male and female thrips trapped in the CFMTs randomly collected from the plots among the treatments. In conclusion CFMT used in medium or high density in the strawberry greenhouse reduced infestation of F. intonsa in the flowers and can be a good addition to integrated pest management tactics against anthophilous thrips.

Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is economically important pest of various crops causing damage through direct feeding and transmitting tospoviruses. In a previous study differential responses of the thrips to various geometrical patterns of yellow sticky card were found. Therefore, in this study, we compared the behavioral responses of the thrips to visual and olfactory cues in cylindrical black box and Y-tube olfactometer, respectively. Multiple or pair wise choice tests were carried out among/between six geometrical patterns of yellow color paper and artificial flowers. The thrips preferred circular shape to other geometrical patterns in multiple choice test. In pair wise choice test between three geometrical patterns, i.e., circular, rectangle, and modified circular, and artificial strawberry flowers, the thrips showed preference to the yellow artificial flower than any other cues. The thrips resided on the yellow artificial flower almost 4 times more than other patterns. In Y-tube olfactometer test, higher number of the thrips chose the arm with p-anisaldehyde and artificial flower compared to the arm with only the artificial flower. Higher number of the thrips also chose the arm containing both visual and real flower odor as compared to arm with the only real flower odor. The potentials and application of these results in the development of attraction traps for the thrips management have been discussed.