톱다리개미허리노린재(Riptortus pedestris Fabricius)는 지역에 따라 사과에 심각한 경제적 피해를 야기하고 있지만, 사과에서 톱다리개미 허리노린재 친환경 방제에 대한 연구는 전무한 실정이다. 따라서, 이번 연구에서는 톱다리개미허리노린재의 집합페로몬 성분 중 (E)-2-hexenyl (Z)-3hexenoate (E2HZ3H)이 노린재검정알벌(Gryon japonicum Ashmead)과 노린재깡충좀벌(Ooencyrtus nezarae Ishii)에 미치는 영향을 조사하였다. 사과 과수원에서 E2HZ3H는 전체 과수원에 발생하는 2종의 포식기생자의 밀도에는 직접적으로 영향을 주지 않았고 이들 포식기생자의 공간분포도 변화시키지 않았다. 그러나, E2HZ3H 루어가 설치된 지역 주변에서는 2종의 포식기생자 모두 제한적으로 유인하는 것을 확인하였다. 따라서, E2HZ3H 루어는 사과 과수원 내에서 정밀방제를 목적으로 친환경 방제에 고려될 수 있을 것으로 생각된다.

As a broad-spectrum insecticide azadirachtin may cause acute toxicity and alter behavior of natural enemies. We evaluatedthe toxicity of azadirachtin on two egg parasitoids of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), Ooencyrtusnezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae), by pre-treatinghost eggs with five concentrations, i.e., 15, 10, 7.5, 5, and 2.5 mL/L. Azadirachtin significantly reduced parasitism byG. japonicum in 15 and 10 mL/L concentrations than other lower concentrations. Similar effect was also observed inO. nezarae. The parasitism reduction capacity (R) for G. japonicum was 40.8 and 33.1% in 15 and 10 mL/L concentrations,but it was 81.6 and 71.4% in O. nezarae, respectively. Based on the IOBC guideline, azadirachtin can be slightly ormoderately harmful to O. nezarae and slightly harmful or harmless to G. japonicum.

Morphology of antennal sensilla and their distribution were investigated in male and female adults of Ooencyrtus nezarae, an egg parasitoid of Riptortus pedestris, using scanning electron microscopy. Antennae of O. nezarae was composed of scape, pedicel and seven flagella in both sexes. Six types of sensilla (s. trichodea, s. basiconica, s. chaetica, s. campaniformia, s. sickle-shaped and unknown s.) were identified from both sexes. Among them, s. trichodea and s. sickle-shaped were multiporous, others are not. They distributed in varying numbers. Sexual dimorphism was clearly observed in the distribution of s. trichodea (only on male antennae) and unknown sensilla (only on female antennae). These findings would be helpful for further studies on detailed sex specific-receptive functions of each antennal sensilla.

톱다리개미허리노린재(Riptortus clavatus)는 콩과 작물을 흡즙하여 작물체를 고사시키거나, 과일을 흡즙하여 반점을 일으키는 등 농작물에 심각한 피해를 주는 해충이다. 이 노린재 해충의 천적인 알깡충좀벌(Ooencyrtus nezarae)은 알에 기생하여 밀도를 감소시키는 잠재적인 생물적 방제인자(biological control agent)로써 역할을 하고 있다. 알깡충좀벌을 인위적으로 대량사육할 수 있는 방법을 개발하고 자, 알기생벌에 기생당한 자연알(natural egg)의 저온보관 방법을 검토하였고, 휘발성 액체로 추출한 카이로몬(kairomone)을 인공알(artificial egg)에 처리하여 알기생벌 의 산란행동 관찰 및 산란을 유도하였으며, 인공먹이(artificial diet)로 알기생벌을 사육하는 과정에서 경험하고 있는 문제점 등을 소개하고자 한다.

Ooencyrtus nezarae lshii (Hymenoptera: Encyrtidae) is a major egg parasitoid of Riptortus pedestris (F.) (Hemiptera: Alydidae). One of the components of the aggregation pheromone of R. pedestris, (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), is known to attract O. nezarae female. Response of O. nezarae females to E2HZ3H and its isomers was studied using electro-antennogram (EAG) and field tests. O. nezarae females showed higher antennal response to E2HZ3H and Z2HE3H isomers than E2HE3H and Z2HZ3H. In field tests, O. nezarae females were attracted to E2HZ3H traps, but not to Z2E3 traps. Interestingly, the blend of E2HZ3H and Z2HE3H showed significant antagonistic activities to the attraction of O. nezarae females in the field. We conclude from this study that Z2HE3H is a potent antagonist to the behavioral response of O. nezarae.

노린재류는 콩, 녹두 등 두과작물을 비롯하여 단감, 참다래, 사과, 배 등 각종 과수와 채소를 가해하지만 방제가 어려운 문제해충이다. 노린재류 알기생봉인 알깡충좀벌(Ooencyrtus nezarae) 방사적기를 포착하기 위하여 콩과 단감 과수원에서 시기별 노린재 발생량을 조사하였다. 톱다리개미허리노린재, 알락수염노린재, 썩덩나무노린재, 갈색날개 노린재, 풀색노린재 5종을 대상으로 모아트랩과 포충망조사를 실시하였다. 모아트랩에서 톱다리개미허리노린재 성충 은 4월 11일부터 9월 하순까지 지속적으로 발생하였다. 콩 포장에서 발생최성기는 5월 상중순과 8월 중하순이었는데, 5월 상중순 포획량 22마리/트랩보다 8월 중하순에 182마리/트랩로 약 10배정도 많이 발생하였다. 한편 단감 포장에서는 5월 중순에 32마리/트랩보다 9월 중순에 457마리/트랩으로 14배 많이 채집되었다. 콩은 개화 및 착협기인 8월 중하순에, 단감은 비대착색기인 9월 중하순이 노린재 피해를 가장 많이 받는 시기이다. 그 외 콩포장에서 트랩에 많이 포획되는 노린재류는 없었는데, 단감원에서는 7월 중순과 9월 상순에 갈색날개노린재 발생량이 다소 높은 경향이었다. 장내에서 알깡충좀벌 발생소장을 조사하기 위하여 노린재 알을 관찰하려고 하였으나 농경지 포장에서 알 관찰은, 특히 톱다리개미 허리노린재는 하나씩 알을 낳기 때문에, 쉽지 않았다. 난괴로 낳은 노린재류 알을 채집하여 실내에서 사육하며 기생여부 를 조사한 결과 5종의 알기생봉을 관찰할 수 있었으며, 정확한 종을 동정중이다.

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.

콩의 해충인 톱다리개미허리노린재(Riptortus pedestris [F.] [Hemiptera: Alydidae])의 주요 천적으로는 노린재깡충좀벌(Ooencyrtus nezarae Ishii [Hymenoptera: Encyrtidae])이 잘 알려져 있다. 본 실험에서는 노린재깡충좀벌의 종내 경쟁 패턴을 이해하기 위하여 기주자원인 톱다리개미허리노린재의 알에서 기생벌의 노출 시간(1, 3, 5일), 노린재 알의 밀도(10, 20, 40개)에 따라 기생벌의 개체수를 달리했을 경우 산란과 다음 세대의 우화를 관찰하였다. 기생벌의 밀도가 높을 경우(3개체) 낮을 때(1개체) 보다 기생벌 개체 당 산란하는 알의 개수가 감소하였고, 노출 시간이 길어짐에 따라 산란하는 알의 감소폭도 컸다. 따라서 노린재깡충좀벌에서 개체군 밀도와 노린재 알에 대한 노출 시간이 종내 경쟁에 영향을 주었지만, 일일 산란수의 시간적 한계성 때문에 기주알의 밀도 증가에 따른 영향은 적었다.

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.

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.

In a previous study, aggregation pheromone trap added with refrigerated eggs of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) in a netted pouch was found to enhance parasitism by its egg parasitoid Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) in soybean fields. However, the eggs released in the netted pouch would not be well exploited by the egg parasitoid due to reduced encounter of the eggs and elevated inter- or intraspecific competition among the parasitoids in clumped condition of released eggs inside the pouch. To solve this problem, new trap was developed with twelve separate cells for egg placement. Efficiency of this new trap was evaluated in a soybean field in Songcheon, Andong. Newly developed trap and formerly designed trap each with 180 refrigerated eggs were placed at a distance of 15-20m in the field. The released eggs were collected every week, and the experiment was replicated for three weeks. In addition, comparison was carried out by placing eggs in different density in the cell (120 in total per trap) for three weeks. Parasitism in newly developed trap (32-35%) was higher than that in the former trap (16-20%). Parasitism in the trap where eggs were released in six cells was the highest, followed by three cells, one cell, and eggs released in the pouch. From these findings, newly developed traps is better than previous design in enhancing the parasitism in soybean fields.

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.

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.

Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) is a gregarious egg parasitoid of Riptortus clavatus Thunberg (Hemiptera: Alydidae) and also attack three other stink bugs in soybean fields. In a previous study the refrigerated R. clavatus eggs were supplemented in soybean fields and found to enhance the parasitism by Gryon japonicum (Hymenoptera: Scelionidae), a sympatric solitary parasitoid of R. clavatus, but not by O. nezarae. Therefore, the R. clavatus eggs refrigerated for 0, 15, 30, 60 and 120 days were evaluated for the parasitization by O. nezarae in the laboratory. The number of parasitized host eggs, number of adult parasitoids emerged, immature mortality, sex ratio, development time, adult longevity, and size of the parasitoids were examined for the parasitoids exposed to or emerged from the refrigerated host eggs. All the attributes examined were not affected by the refrigeration of host eggs for up to 60 days. In addition, refrigeration did not change the reproduction capacity of the emerged adult parasitoids nor the biological attributes of their offsprings. In the evaluation of post-refrigeration period of the host eggs, O. nezarae parasitized the eggs successfully for the first 4 days after the refrigeration at 26.3ºC and 78.7% RH conditions. Since O. nezarae can parasitize the eggs of R. clavatus that were refrigerated up to 60 days, the underlying reason for the no-change in parasitism by O. nezarae in the field supplemented with refrigerated host eggs is in further investigation.

경남진주의 콩포장과 대학 캠퍼스에서 톱다리개미허리노린재의 집합페로몬을 사용하여 난기 생봉인 Ooencyrtus nerarae(Hymenoptera: Encyrtidae)의 발생소장을 조사하였다. 2003년과 2004년에 대학 캠퍼스에 설치된 트랩에 유살된 암컷의 수는 수컷 유살수의 317.5배와 103.4배이었고, 2004년 콩포장에서는 12.6배이었다. 콩포장에서 O. nezarae의 암컷은 8월 하순부터 유살되기 시작하여 9월 20일 전후에 가장 많이 유살되었다. 2003년과 2004년에 대학 캠퍼스에서는 8월 중하순부터 밀도가 증가하여 9월 상중순에 최성기를 나타내었다. 두 조사지역에서 모두 10월 이후에는 거의 발생하지 않았다. 톱다리개미허리노린재의 집합페로몬 세 성분, 즉 (E)-2-hexenyl (Z)-3-hexenoate(E2HZ3H)와 (E)-2-hexenyl (E)-2-hexenoate(E2HE2H) 및 myristyl isobutyrate(MI) 중에서 E2HZ3H 만이 O. nerarae에 대해 유인력을 나타내었다. E2HZ3H:E2HE2H:MI를 7:36:7로 배합한 것보다는 20:20:10이나 16.7:16.7:16.7으로 배합한 트랩에 더 많은 수가 유인되었는데, 이는 배합된 E2HZ3H의 량 때문인 것으로 추정된다.