Morphology of antennal sensilla and their distribution were investigated in male and female adults of Gymnosoma rotundatum, a parasitic fly to hemipteran species, using scanning electron microscopy. The overall length of antenna was not different between male and female. Antenna of G. rotundatum was composed of scape, pedicel and funiculus in both sexes. Three types of sensilla (sensillum basiconica, s. chaetica and s. coeloconica) were identified from both sexes, in varying numbers and distribution along the antennae. The two sensillum types were further divided into different subtypes; s. basiconica into three subtypes and s. chaetica into two subtypes. Among sensilla, s. basiconica subtype 1, 2 and 3 were multiporous, indicating that the ir primary function is olfactory, and others were not. The s. basiconica was most numerous on the antennae in both sexes. The number of subtype 1 of s. basiconica was different between male and female. The morphological information obtained in our study provides a basis for electrophysiological and behavioral studies of the olfactory sensory function of each morphological type of sensilla. (Supported by PJ011756022018, RDA)

This study was carried out to confirm the parasitic and developmental features of A. japonica and D. suzkii was used as a parasitic natural enemy. A. japonica attacked the D. suzukii larvae and the emergence of adults were observed from D. suzukii pupae. Black spots were observed in parasitized D. suzukii larvae. Mortality of parasitized larvae, rate of parasitic and developmental feature were investigated according to developmental stages of host, D. suzukii. Mortality and rate of parasitic of D. suzukii larvae were the highest when second instar larvae were attacked. Developmental period of parasitized D. suzukii larvae showed differences to developmental stages, but there was no significant difference in developmental stage of pupal period.

One species of the genus Aphidius (Hymenoptera: Braconidae: Aphidinae) is recognized in this study. The genus Aphidius is a large braconid group distributed in the European, Palaearctic and Oriental regions, which includes currently 61 species in South Korea. This genus mainly parasitizes aphids. In this study, Aphidius transcaspicus Telenga, 1958 is recognized for the first time in South Korea. Historically, Aphidius transcaspicus is complexed with Aphidius collemani species complex. Descriptions, diagnosis distribution and illustration are provided.

The genus Diadegma is a well-known parasitoid group and some are known to have symbiotic virus so called polydnavirus (PDV, more specifically Ichnovirus, IV). The presence of the IV in the Diadegma species a has already been identified more than a decade ago. Previously we reported a DfIV, 62 genomic segments, 247kb from D. fenestrale which parasitized wide range of lepidopteran species (Generalist). However, DsIV from D. semiclausum which parasitized in the P. xylostella (Specialist) has 48 genomic segments, 208kb. Finally, 123 ORFs were re-annotated (repeat element protein, 41; cysteine motif protein, 11; viral innexin, 6; viral ankyrin, 8; polar residue rich protein, 7; N gene, 3; Neuromodulin protein, 2 and not assigned gene, 45). DsIV also have most of lepidopteran immunosuppression gene families and 103 ORFs annotated (repeat element protein, 36; cysteine motif protein, 8; viral innexin, 7; viral ankyrin, 6; polar residue rich protein, 7; N gene, 3; and not assigned gene, 36). Certainly, although viral species specific segments exists, two IVs showed high similarity in most of segments. However DfIV have some more number of that genes such as cysteine motif protein and viral ankyrin. Two Diadegma species also showed difference in mitochondrial genome structure. Therefore we concluded that two species has their own evolutionary linage depending on the lepidopteran hosts with its own symbiotic virus.

Since first reported in 1988 the Pine Wilt Disease has been established and spreaded nearly nationwide in South Korea, causing tremendous economic damage in pine forests. The pine wilt nematode (Bursaphelenchus xylophilus), causing the Pine Wilt Disease, in Korea is known to be transported by two insect vectors that are Monochamus alternatus Hope and Monochamus saltuarius Gebler. Currently the pest management strategy largely relies on pesticide application and infected tree clearing. The aim of the present study was to search for early larval parasitoids of M. alternatus using the sentinel log infested with the cerambycid eggs. Only one braconid species was collected and identified as Spathius verustus Chao. Two to ten wasp larvae attached and fed on one host larva. Parasitism rate was 55.5 to 59 % in Jinju site, while 1 to 18.1 % the other sites. Sex ratio was female-biased (female : male = 18.9 : 1). The S. verstus has potential to be use as parasitic natural enemy of M. alternatus.

Lethal concentration of Beauveria bassiana (Strain GHA, Botanigard, Arysta LifeScience) against Riptortus pedestris (F.) (Hemiptera: Alydidae) was compared with that of its’ parasitoid Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae). Five concentrations of the mycoinsecticide, i.e., 5×108, 1×108, 2×107, 4×106, and 8×105 conidia/ml, were used. Glass scintillation vial was coated with 100 μl solution, and insects were released and assessed up to 12 hours. The LC50 and LC20 of second instar R. pedestris were 1.8×1010 and 1.5×108 conidia/ml, and those of O. nezarae were 1.9×107 and 2.8×106 conidia/ml, respectively. The mortality of O. nezarae was observed 3.9 times higher than R. pedestris in higher concentration. This result shows that O. nezarae is more susceptible to the mycoinsecticide than R. pedestris.

The species composition of the parasitoid complex and the degree of parasitism by each species were analyzed for Ivela auripes Butler (Lepidoptera, Lymantridae) populations in the increasing phase. Total of 2,177 eggs, larvae and pupae were collected and reared from the Gwangneung forest Pocheon-si, Korea. The most abundant parasitoids from each developmental stage were: a trichogrammatid wasp (Trichogramma kurosuae) from eggs, a braconid wasp (Cotesia melanoscela) from larvae, an ichneumonid wasp (Pimpla disparis) and a tachinid fly (Tachinidae sp.1), each from pupae. 19 other parasitoids, mostly hyperparasitoids, also occurred including Tachinidae sp.2, Pteromalidae sp.1, Ichneumonidae sp.3, and Apechthis capulifera. Illustrations and a list of the species parasitizing of I. auripes are provided.

꽃매미(Lycorma delicatula)의 천적인 벼룩좀벌 일종(Anastatus orientalis Yang et Gibson(Hymenoptera : Eupelmidae))의 자연 상태에서 기생율을 조사한 결과: (1) 산동성 Yantai 에서 가장 높은 69.0%의 꽃매미 난괴가 기생 당하였고; (2) 최고 기생율은 33.0%로 북경시 하이디엔(Haidian) 지역에서 관찰되었고; (3) 기생봉의 알은 산시성의 양링(Yangling)에서 가장 빨리 부화하였으며, 천진시의 옌타이(Yantai)와 광앙(Guangang) 지역, 하북성의 친황다오(Qinhuangdao), 하이디엔(Haidian)에서 약간의 차이를 보였으며; (4) 성비는 채집된 지역에 따라 1.3에서 1.9로 다양하였고; (5) 꽃매미 난괴에 대한 기생율은 기주식물인 Populus sp., Salix sp. Toona sinensis에서 유의할 만한 차이가 관찰되지 않았으며, 최고기생율은 T. sinensis에서 64.3%로 나타났고, Ailanthus altissima에서는 27.4%로 가장 낮았다. (6) 꽃매미 알에 대해서도 꽃매미 알이 발견된 기주식물별로 차이가 없었고, 평균 30.0%의 기생율을 나타냈다.

Anatatus orientalis is an important natural enemy parasitizing eggs of lanternfly Lycorma delicatula White. In order to effectively utilize this parasitoid, the parasitism rates of lantern-fly and emergence of its parasitoid were surveyed in different areas. Results showed that the emergences of wasp Anatatus orientalis from different areas had significant differences. Those parasitoids emerged from lantern-fly eggs collected from Yangling of Shaanxi province, Qinhuangdao of Hebei province, and Dagang District of Tianjin City came out focus on May only, while wasps from Yantai of Shandong province showed 2 obvious emergence peaks in May and September respectively. Wasp populations with emergence asynchrony in Yantai area were analyzed by different periods. Results revealed that the emergence percentages in spring (May) were significantly lower than that in fall (September), but the sex ratios did not differ significantly between the two seasons. The emergence asynchrony of parasitoid may be induced by the diapause of species, which is a long-term coevolutional outcome of parasitoid with host for maintaining its population. These findings provided some scientific bases for the rational utilization of this parasitoid in practice.

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.

Anatatus orientalis (Hymenoptera: Eupelmidae) is aparasitic natural enemy of the lantern-fly Lycorma delicatula (Hemiptera:Fulgoridae) in China. It can complete 6 generations from April to December in a year under laboratory conditions. It takes 18-28 d for development of one generation at about 25℃. Under the room temperatures of 23-25℃, the developmental duration of eggs is 1-2 days, 10 days for larvae, 4 days for prepupae and 7 days for pupa stage. A. orientalisis a mono-parasitic wasp in the eggs of L.delicatula and its female can oviposit 9.18 eggs on average. The oviposition period is 5-20d. The adults can survive 4-7d on average without supplying any nutrition. While feeding with 20% honey solution, the female adult longevity can reach 25 days on average.

Population dynamics of maize weevil, Sitophilus zeamais, and their parasitoids Anisopteromalus calandrae were examined while considering the spatio-temporal interactions using population modelling as a tool. The modelling of two species host-parasitoid systems identified the some factors concerning the long-term dynamics of interacting populations. In the single host system, the total density of S. zeamais increased exponentially and reached a saturated, asymptotic level with time. This stabilization in the density could be explained by the spatio-temporal dynamics among the patches. S. zeamais disperses continuously from patches of high density to those of low density. This density-dependent dispersal could be one of the mechanisms for stabilizing the S. zeamais population density. In the S. zeamais-A. calandrae system, both populations showed long-term coexistence. The long term coexistence could be attributed to spatio-temporal interactions of S. zeamais and A. calandrae resulted from dispersal of host and a non-random searching behavior of the parasitoid. Because such spatio-temporal variation in population dynamics, the overall host-parasitoid system may have been in a stable state, although the local population system in each patch was unstable.

Terrestrial toxic effects of soil arsenate were studied using a model system consisting of Capsicum annum, Myzus persicae, Aphidus colemani. We investigated the transfer of arsenic from soil to aphid and toxic effect of elevated arsenic on each trophic level. Artificial soil was treated with arsenate at 0, 2 and 6 mg/kg, then arsenic concentration of soil, plant tissues (root, stem, leaf) aphids were measured to observe the arsenic transfer. Toxic effects of elevated arsenic concentrations on each species were investigated at population level. Physiological and biochemical responses of plant and aphid were observed. In addition, enzyme activities against reactive oxygen species (ROS) induced by arsenic stress were also investigated. Host choice capacity and parasitism success of the parasitoids were examined. The results suggest that arsenic concentration in plant tissues and aphids were elevated with increased concentration of arsenic in soils. Physiological responses of plants were not affected by soil arsenic but there was change of biochemical responses. Decreased fecundity and honeydew excretion of aphids were observed, elevated activity of antioxidant enzymes indicated that aphids received the ROS stress induced by arsenic. Decreased eclosion rate of parasitoids were observed with increased arsenic treatment in soil. The results showed low concentration of arsenic in soil can transfer through food chain and can impact on higher trophic level species.

화랑곡나방 유충이 자유롭게 수직적 분포를 하도록 허용된 아크릴 실린더(지름 150 mm, 높이 85 mm, 현미 660 g 포함)에서 보리살이나 방고치벌 공격에 대응하는 화랑곡나방 유충의 행동반응을 용화장소 선택행동을 중심으로 평가하였다. 보리나방살이고치벌이 없을 때는 화랑곡 나방 유충의 용화가 표층(< 5 mm)에서 이루어졌으나 보리나방살이고치벌이 존재하는 경우 유충은 더 깊은 층에서 용화하였다. 보리나방살이고 치벌의 기주 탐색은 주로 표층에서(< 5 mm) 이루어 졌으며, 따라서 화랑곡나방 유충은 표층보다 깊은 층에서 용화함으로써 공격을 피할 수 있었다. 유충의 용화 장소 선택은 기생자의 공격에 대한 효과적인 방어 행동으로 판단되었다. 이러한 유충의 방어 행동은 보리나방살이고치벌의 수반응에는 영향을 미치지 않았는데, 이는 알려진 바대로 보리나방살이고치벌이 기주 유충 당 산란 수를 피공격 유충 수에 따라 조절하기 때문이라고 생각된다. 본 실험에서도 공격된 화랑곡나방 유충 수가 감소하면서 기주 유충 당 고치벌의 산란 수는 증가하였다.

Potato tuber moth (PTM), Phthorimaea operculella (Zeller), is a serious pest of potato (Solanum tuberosum L.) plants in the fields from warm temperate to tropical climates, and tubers stored under ambient temperatures post-harvest. In recent years, concerns on PTM occurrence and damage to potato are increasing due to climate change resulted in global warming. To search potent natural enemies of PTM, we collected >150 PTM larvae from potato fields in Jeju-do in May, 2009 and then reared in the room until wasp adults emerging, which was identified by Lee J.W. as Diadegma fenestrale (tentative Korean name, 감자뿔나방맵시벌). This is the first report in Korea. When supplied 10% sugar solution on adults to rear, the longevity was 12.2±2.0 day, which was much longer than supplied with only water (5.0±1.4 day) or none (3.1±1.1 day). When the 2nd larvae of PTM, 10 days after hatch, dwelled in potato tubers were supplied to parasitoid adults for parasitization, the developmental periods from egg oviposition to adult emergence was 24.0±2.9 day, and the sex ratio of newly emerged adults was 0.27. The parasitization ratio indoor showed a kaleidoscopic characteristics, ranged from 30.0% to 71.4%. It represented that many factors might be related for the successful parasitization to PTM larvae.

 ,  , Effect of a new crop protectant ‘Bt-Plus’ on natural enemies was analyzed in this study. Tested natural enemies included two parasitic species of Aphidius colemani and Eretmocerus eremicus, and four predatory species of Harmonia axyridis, Orius laevigatus, Amblyseius swirskii, and Phytoseiulus persimilis. ‘Bt-Plus’ was formulated by combination of three entomopathogenic bacteria (Xenorhabdus nematophila (Xn), Photorhabdus temperata subsp. temperata (Ptt), Bacillus thuringiensis (Bt)) and bacterial metabolite (BM). All three types of ‘Bt-Plus’ showed significantly higher toxicities against fourth instar Plutella xylostella larvae than Bt single treatment. Two types of bacterial mixtures (‘Xn+Bt’ and ‘Ptt+Bt’) showed little toxicity to all natural enemies in both contact and oral feeding assays. However, ‘BM+Bt’ showed significant toxicities especially to two predatory mites of A. swirskii and P. persimilis. The acaricidal effects of different bacterial metabolites were evaluated against two spotted spider mite, Tetranychus urticae. All six BM chemicals showed significant acaricidal effects. The BM mixture used to prepare ‘Bt-Plus’ showed a high acaricidal activity with a median lethal concentration at 218.7 ppm (95% confidence interval: 163.2 - 262.3). These toxic effects of bacterial metabolites were also proved by cytotoxicity test against Sf9 cells. Especially, benzylideneacetone, which was used as a main ingredient of ‘BM+Bt’, showed high cytotoxicity at its low micromolar concentration.

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.

The larval parasitoid, Bracon hebetor, attacks third or older larvae of indianmeal moth (Plodia interpunctella), which results in laying eggs or simply paralyzing the larvae. We studied the influence of the parasitoid’s attack on the larval development of indianmeal moth. The third larval instars of the same age were collected from the experimental colonies and each larva introduced in an acrylic cube (2 x 2 x 2 cm) treated with: 1) empty, 2) three rice grains, 3) three rice grains and a female parasitoid without ovipositor (by removing) and 4) three rice grains and a paralyzed larva. The larval activity in the experimental cube was photographed every five minutes until the larva died or pupated. Only the larvae in the cube with paralyzed larvae could pupate and emerge. The other larvae in the three treatments died before pupating, although the survival time was significantly different in relation to the treatment (F=5.27; df=2,14; P=0.019); the larvae in the empty cube had a shorter survival time than those in the rest of treatments. The results indicated that the paralyzed larvae could be fed by the health larvae and contribute to prevent population crush in the situation of food shortage with the presence of the parasitoids. The host parasitoid interaction between indianmeal moth and Bracon hebetor might not always be negative to the indianmeal moth population.

Diprion hani Smith and Cho was first reported as a new species from South Korea in 2007. Major outbreaks occurred in September 2007. Outbreaks were restricted geographically to only three inland areas of central Korea where had previously been reforested with Korean white pine, Pinus koraiensis Seib. & Zucc. The outbreak areas were approximately 50 km in diameter. The sawfly populations decreased drastically in 2008. Environmental factors of the outbreak sites were investigated as a first step to characterize the sites and to understand the population dynamics of the sawfly. During the outbreak in 2007, the average temperature of the sites were 1.3℃ higher than the 30 years average, and the annual precipitation was 384 mm higher than the average from 1971 to 2000. In addition, Monodontomerus dentipes (Dalman), a well-known torymid parasitoid of many sawflies, is reported as a gregarious cocoon parasitoid of D. hani.

Diamondback moth (DBM, Plutella xylostella L.), the most destructive pest of cruciferous crops, is well-known as typical subtropical insect pest. A number of biological agents such as diseases, parasites and predators can affect populations of DBM in the fields negatively. In previous reports, we suggested Cotesia glomerata, Diadegma semiclusum, and Microplitis plutellae as promising natural enemies to DBM control at highland areas, but these species are larval parasitoids. In 2004~2009, we searched highland fields cultivating various cruciferous crops for PUPAL parasitoids which can supplement the unsatisfactory parasitism in the augmentative release of larval parasitoids. We obtained adults of hymenopteran parasitoid from DBM pupae in early July at Hoengseong region (asl 540 m), and then identified as Diadromus sp., although being a critical species so far. This parasitoid showed high rate of parasitism, about 13.2%, in mid October at the same region. Development period from oviposition to emergence of Diadromus sp. ranged from 14 to 18 days under 23℃ condition. Adult longevity, > three weeks, was longer when it was provided with 10% sugar solution as food than with water only or without food. Male adults mated as soon as emerging from parasitized DBM pupae, and laid eggs into DBM pupae for a week. Parasitism by Diadromus sp. was highest on 7th day after emergence. In contrast, lethality of DBM pupae which were not parasitized by wasps showed 60% on average for seven days. Parasitized DBM pupae could be stored at 10℃ for two weeks. The simultaneous augmentative release of larval parasitoids and pupal parasitoids can be an important component to integrated DBM management program in the future.