Riptortus pedestris (F.) (Hemiptera: Alydidae) is an important pest of soybeans in Korea and Japan. A synthetic aggregation pheromone trap has been commercialized and used in soybean fields in Korea for both monitoring and mass-capture of this bug. As the trap’s efficacy in reducing the pest population or crop damage is unknown, in this study we evaluated the aggregation pheromone trap in experimental soybean fields located in Andong National University. Two treatments, one with traps deployed for the entire cultivation period and one with no traps, were tested in six small experimental fields. The total numbers of R. pedestris (in all life stages) in soybean field were not significantly different between the treatments until August. But, in presence of pheromone, the pest’s abundance increased significantly in September and October. Relative to the size of the bug population in the field, trap catch rate was low during the fall (when bug density was highest) and high in early summer when the field population was very low. Placement of aggregation traps in plots caused pod and seed damage from R. pedestris to increase 2.7 and 2.2 times compared to the control. In conclusion, R. pedestris populations increased significantly during the fall in the presence of the aggregation pheromone trap, which should therefore be used with great caution whether as a control measure or as a monitoring tool.

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 western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has been considered as a major thrips species after its invasion in 1993 in Korea although recently F. intonsa (Trybom) was found as a dominant species locally. To explain their asymmetrical abundance in the field, we hypothesized differential insecticide susceptibility of both thrips species as an underlying mechanism. Laboratory assays were conducted to know their susceptibility to different pesticides including chlorfenapyr, chlorpyrifos, thiamethoxam, spinosad, s-metolachlor, and metalaxyl by direct spray, residue, and oral ingestion. Results showed that both thrips species were highly susceptible to chlorfenapyr and mortality reached 100% within 12 hours in F. occidentalis in all the assays while 9 hours in F. intonsa in direct spray and residual assays. The LT50[h] values of tested insecticides were significantly lower than that of herbicide or fungicide regardless of exposure methods except metalaxyl from direct spray. The insecticides tested here differed considerably in species specific toxicity, and F. intonsa is generally more susceptible to the insecticides irrespective of exposure methods.

Frankliniella occidentalis (Pergande) is an anthophilus pest of many greenhouse and field crops worldwide. We compared the influence of constant (27.3ºC) and fluctuating temperatures (23.8 to 31.5ºC, with an average of 27.3ºC) on the life table characteristics of F. occidentalis held at a 16:8 h L:D photoperiod and 45 ± 5% RH. The development times from egg to adult of F. occidentalis were significantly affected by temperature fluctuation and sex. Survival of immature life stages was higher under fluctuating than constant temperature. Total first instar larvae/female was not significantly different (58.7 at constant and 60.5 at fluctuating temperatures) but daily production of first instars was higher in constant temperature than fluctuating temperatures (3.3 at constant temperature and 3.1 at fluctuating temperatures). The off-spring sex ratio was not significantly different between constant and fluctuating temperatures. The intrinsic rate of natural increase (rm), net reproductive rate (R0), finite rate of increase (λ), mean generation time (tG), and doubling time (tD) were affected significantly by fluctuation of temperature. The intrinsic rate of natural increase of F. occidentalis was higher in constant temperature (0.1808) than did in fluctuation of temperatures (0.1733). Thus, this study show that variable temperatures influence population growth rates of F. occidentalis.

Winter cherry bug, Acanthocoris sordidus Thunberg (Hemiptera: Coreidae) is a pest of Solanaceous and Convolvulaceous crops and distributed in Taiwan, Japan, and Korea. Adult female generally lays eggs in cluster on host plant leaves. Most researches have been conducted in Japan, and it is regarded as a minor pest. In this study, we surveyed the seasonal population change of A. sordidus and its damages from May to September by visual count in experimental pepper fields located in Andong National University, where no pesticide was sprayed. Hatchability was measured using field-laid egg mass covered by nylon-meshed pouch. Potential disease transmission was confirmed in filed pepper fruits confined for a week with two adult A. sordidus inside nylon-meshed pouch. Adults and eggs of A. sordidus started to appear in 30th May and 10th June, respectively. Nymph populations were first found on 10th July. No eggs were found from 7th September when highest adult population (67/plant) was recorded. Hatchability was over 90% in the field. No disease transmission to pepper fruit was observed. We believe that A. sordidus would become a serious pest under a certain condition such as low level of insecticide use and climate change.

The greenhouse whitefly Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) is a phloem-feeding pest that causes serious damages in vegetables and ornamental crops by direct feeding and causing diseases such as sooty mold. For the better management of T. vaporariorum, within-greenhouse and -plant distribution of this pest was investigated in strawberry greenhouses in Andong. Ten strawberry plants for each category were randomly selected and examined. Adults per plant was recorded by visual observation, and eggs and nymphs per trifoliate leaf were counted under microscope. Adult, egg, and nymph populations were all more abundant in border rows than in middle rows. The number of nymphs were found more in lower canopy in both border and middle rows, but egg density was higher in upper canopy of border plants. No correlation was found between sticky trap count and population density on plants. These informations would be important for the development of efficient monitoring and control measures of greenhouse whitefly.

Riptortus pedestris is an important soybean pest in Korea and Japan. Aggregation pheromone traps were evaluated in 12 soybean fields in Andong using three treatments of trap installation, i.e., installation for whole cultivation period, installation up to September, and no installation. The number of R. pedestris (in all life stages) were not significantly different among the treatments until October, but its abundance significantly increased at mid October in the fields where traps were installed. Trap catch of R. pedestris was relatively higher in August while bug population was low in the fields. However, in fall, R. pedestris populations become abundant in the fields while trap catch was low. There was no significant difference in parasitism as well as seed and pod damage among the treatments. In conclusion, aggregation pheromone trap should’nt be used as control measure, but can be used as a monitoring tool of R. pedestris population up to August in soybean field.

Tetranychus piercei McGregor, T. truncatus Ehara, and T. bambusae Wang and Ma are considered as major pests of many agricultural crops in Bangladesh. T. piercei and T. truncatus has a diverse host plants although T. bambusae infest only bamboo leaves. We compared the development, survivorship, and life table parameters of T. piercei and T. truncatus on bean leaves and T. bambusae on bamboo leaves at 25ºC, 60-70% RH, and a photoperiod of 16: 8 h (light: dark). The development time from egg to adult female of T. piercei and T. truncatus was 10.2 and 8.8 days when feeding on bean leaves, respectively, whereas it takes 9.5 days for female T. bambusae when feeding on Bambusa sp. leaves. Mated females of T. piercei, T. truncatus, and T. bambusae laid on average 186.9, 132.5, and 46.3 eggs for the oviposition period of 22.3, 13.5, and 20.2 days, respectively. The intrinsic rate of increase (rm) was 0.268 for T. piercei, 0.295 for T. truncatus, and 0.178 for T. bambusae. The finite rate of increase (λ) was 1.31, 1.34, and 1.20 individuals/female/day for T. piercei, T. truncatus, and T. bambusae, respectively. The doubling time (Dt) was lowest in T. truncatus (2.4 days) compare to T. piercei (2.6 days) and T. bambusae (3.9 days). The two polyphagous Tetranychus mites collected in Bangladesh are found to have similar life table parameters fall within the parametric range of other Tetranychus mites found in various regions irrespective of food sources. This is the first report of life table parameters of monophagous T. bambusae.

Frankliniella occidentalis (Pergande) and F. intonsa (Trybom) have been shown asymmetrical occurrence pattern in pepper and strawberry fields. To explain this phenomenon, interactive influence of temperatures (20, 25, and 30ºC) and relative humidities [Low (50-55%), Medium (70-75%), and High (90-95%)] were assessed on pupal and adult stage of the two thrips species. In pupal stage, mortality of both species decreased as the humidity increased without significant difference between the species. Also, pupal duration of the two thrips decreased as RH increased from low to high in all the temperatures tested, but significantly shorter duration was found in F. intonsa. In adult stage, F. intonsa survived better than F. occidentalis only in high humidity at both 20 and 25ºC. Frankliniella intonsa survived 2.5 and 2.4 times longer as RH increased from low to high at 20 and 25ºC, respectively, whereas F. occidentalis survived 1.8 and 1.6 times longer, respectively. In conclusion, both pupae and adults of F. intonsa performed better at higher RH condition compared to F. occidentalis. Thus, difference in relative susceptibility to changing environmental condition can be one of the underlying mechanisms for the differential occurrence pattern in the fields.

Riptortus pedestris (Hemiptera: Alydidae) is known to occur in barley field during spring. But, it is unlikely that R. pedestris can find host resource to reproduce in the spring season. To test this hypothesis, we assessed the reproduction of R. pedestris population collected from field from March to September. Riptortus pedestris were collected at intervals of three days from 15th of each month. Females of R. pedestris collected from trap were provided with just water in a breeding dish, and eggs laid were collected daily. Quality of R. pedestris eggs at each month was also evaluated by providing them as host resource to two egg parasitoids. The collected eggs were divided into three groups and tested for hatchability and parasitism by two egg parasitoids, respectively. As a result, R. pedestris population collected in March and April did not reproduce, and fecundity and proportion of reproduced females were the highest in August. But, neither hatchability nor parasitism rate of R. pedestris eggs show significant difference among the sampling months. In conclusion, R. pedestris starts to reproduce from May, and fecundity reaches highest on August. No change in egg quality was found among the study periods.

Frankliniella occidentalis (Pergande) and Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) are sympatric thrips species infesting crops including strawberry and pepper. Recently, F. intonsa was found as a dominant species locally even though F. occidentalis has been considered as a major species in Korea. We suggested interspecific competition as a underlying mechanism for the asymmetrical abundance. Effect of the competition on adult reproduction and longevity of the two thrips species was assessed in leaf cage and microtube arena, respectively. The number of reproduced progeny was reduced by 79% for F. occidentalis and only 43% for F. intonsa in competition condition. The mean longevity was also reduced greater in F. occidentalis (by 41%) than in F. intonsa (23%). Based on these results, it is probable that interference competition exists between the two species, and F. intonsa is better competitor than F. occidentalis. Therefore, interspecific competition might affect field occurrence pattern of the two thrips species.

The bean bug, Riptortus pedestris (F.) (Hemiptera: Alydidae) is one of the most important polyphagous pests in soybean in Korea and Japan. With the review of previous studies on the suitability of different diets, we additionally tested two leguminous plants as food sources of R. pedestris by assessing development and reproduction of the bugs. The tested diets include seeds of acacia, two mung bean varieties (var. Eoul and Dahyeon), and soybean (var. Daewon). Riptortus pedestris fed on mung bean var. Eoul showed higher nymphal mortality than those fed on mung bean var. Dahyeon, acacia, and soybean. On acacia, development time and preoviposition period of R. pedestris was shortest among the tested diets Also, five day fecundity the highest in bugs fed on acacia seeds. These results showed that acacia seed can be a good quality diet for R. pedestris, and both acacia and mung bean could be a suitable host resources for R. pedestris during the period when soybean, a major host crop, is unavailable.

Riptortus pedestris (F.) inflict losses on a wide range of crop plants. Biological control is an alternative approach to reduce the bean bug population. Scelionid Gryon japonicum (Ashmead) and Encyrtid Ooencyrtus nezarae Ishii are the major egg parasitoids of R. pedestris. The aggregation pheromone of R. pedestris serves as a kairomone to its egg parasitoids. A new tool was developed using aggregation pheromone in a trap which attracts both con-specific bugs and the parasitoids. Non viable host eggs were added with the trap so as to provide resource for the attracted parastioids to multiply. Several studies were conducted to develop this new tool for trapping of the bugs and enhancing parasitism simultaneously. Aggregation pheromone trap added with host eggs was found to increase temporal parasitism in field by 44% compared to the parasitism without host eggs. Higher parasitism (up to 91%) was found in the sites where aggregation pheromone trap added with host eggs was installed compared to control sites. In order to improve this tool, a new device with twelve sections to hold eggs and to be attached to the pheromone trap was designed to provide maximum exposure of the eggs to the parasitoids and to minimize the competition among the parasitoids. Parasitism and number of female R. pedestris trapped in new device attached trap were higher compared to the conventional. With better performance in trapping R. pedestris and enhancing parasitism, the tool would serve as an IPM technique that targets killing the pest and enhancing activity of the pest’s natural enemy simultaneously.

Frankliniella occidentalis Pergande and F. intonsa Trybom (Thysanoptera: Thripidae) are polyphagous insect pests on numerous crops. These two species reduce the crop production in two ways: by sucking sap from the plant parts and by serving as vectors for tospoviruses. In this study, we tried to confirm the previous observation of F. intonsa dominance on certain crops during recent years. Thrips populations were examined on greenhouse strawberry by installing circular yellow sticky cards with black background and on field pepper by destructive sampling of pepper flowers during season of 2012 in Songcheon, Andong. Eighty two to 92% and 3-5% of thrips collected from the both crops were F. intonsa and F. occidentalis respectively. Frankliniella. intonsa was 4-8 times more abundant than F. occidentalis in sticky cards and on pepper flowers. In conclusion, asymmetrical dominance of F. intonsa was found both in strawberry and pepper plant as we found in past on those crops. Underlying reasons such as interspecific competition and climate change were discussed.

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.

WCl6-EtAlCl2 촉매계를 이용하여 비교적 큰 분자량을 갖는 폴리(페닐아세틸렌)을 합성하였다. 중합반응이 잘 진행되었으며 중합수율은 81%였다. 합성한 폴리(페닐아세틸렌) 분자구조를 NMR(1H-,13C-), IR, UV-visible, 원소분석 등으로 분석한 결과 페닐 치환기를 갖는 공액구조 고분자가 합성되었음을 확인할 수 있었다. 아울러 332 nm의 빛으로 여기시킬 경우 PL 최대 peak는 424 nm에서 관찰되었는데, 이는 2.93 eV의 광 에너지에 해당한다. 이 고분자의 순환 전압전류 그림은 도핑과 탈도핑사이에서 비가역적인 전기화학적 거동을 보여주었다. 이 고분자의 전기화학적 과정이 매우 안정하였으며, 스캔속도에 따른 산화전류 밀도 실험으로부터 이 고분자의 산화-환언 과정은 확산-제어과정에 따르는 것으로 분석되었다.

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.

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are generally known to be unsuitable food for the fruit-spotting bugs, dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, nymphal mortality, preovipositional period, fecundity, and adult size in the laboratory. None of 1st instar R. pedestris fed only on a fruit of apple or sweet persimmon became second instar nymph. When provided with soybean seeds together, both the fruits did support the nymphal development and the reproduction of R. pedestris. However, diets including soybean and one of the fruits were not better than control diets consisting of soybean seeds with or without vitamin C. Therefore, apple and sweet persimmon are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on the fruit trees, thus explain absence of either their eggs or their nymphs on the fruit trees in the fields.

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.