Reproduction potential of Riptortus pedestris collected in aggregation pheromone trap and evaluation of their eggs as host resources of egg parasitoids

Eunmok Kim,June-Yeol Choi,Un Taek Lim 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.10

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.

Fruits of apple and sweet persimmon are not essential food sources for Riptortus pedestris (Hemiptera: Alydidae) which causes fruit-spotting

Eunmok Kim,임언택 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.2

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are unsuitable food for some fruit-spotting bugs, the dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated harvested fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, immature mortality, preovipositional period,fecundity, and adult size in the laboratory. No first instars of R. pedestris that were fed only apple or sweet persimmon fruits became third instar nymphs. When supplemented with soybean seeds, both fruits supported nymphal development and reproduction of R. pedestris. However, fruits combined with soybean seeds were not a better diet than soybean seeds only. Therefore, apples and sweet persimmons are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on fruit trees, thus explaining the absence of eggs and nymphs of this bug on fruit trees in orchards.Management of nearby vegetation of fruit orchards would be important for reducing damage by adult R. pedestris. Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are unsuitable food for some fruit-spotting bugs, the dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated harvested fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, immature mortality, preovipositional period,fecundity, and adult size in the laboratory. No first instars of R. pedestris that were fed only apple or sweet persimmon fruits became third instar nymphs. When supplemented with soybean seeds, both fruits supported nymphal development and reproduction of R. pedestris. However, fruits combined with soybean seeds were not a better diet than soybean seeds only. Therefore, apples and sweet persimmons are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on fruit trees, thus explaining the absence of eggs and nymphs of this bug on fruit trees in orchards.Management of nearby vegetation of fruit orchards would be important for reducing damage by adult R. pedestris.

Seeds of Leguminous Plants, Acacia and Mung Bean as Food Sources of Bean Bug, Riptortus pedestris (Hemiptera: Alydidae)

Eunmok Kim,Un Taek Lim 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.04

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.

Nymphal development and reproductive activity of Riptortus pedestris (Hemiptera: Alydidae) fed on soybean seeds and fruits of apple and sweet persimmon

Eunmok Kim,Un Taek Lim 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.10

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.

Effect of Food Deprivation Period on the Development and Reproduction of <i>Riptortus pedestris</i> (Hemiptera: Alydidae), and Its Egg Parasitism

Kim, Eunmok,Lim, Un Taek Oxford University Press 2014 Journal of economic entomology Vol.107 No.5

가교된 미세다공성 고분자 기반 유기용매 나노여과용 초박형 중공사 분리막 개발

양은목(Eunmok Yang),최희철(Heechul Choi),Yejin Liang,Numan Yanar,김민범(Minbeom Kim),박호식(Hosik Park) 대한환경공학회 2021 대한환경공학회 학술발표논문집 Vol.2021 No.11

Evaluation of three plant seeds as potential pre-season diets for Riptortus pedestris

Kim, Eunmok,Park, Chang Gyu,Lim, Un Taek 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) is a polyphagous pest causing serious economic damage especially in soybean (Glycine max L.). R. pedestris start to emerge earlier in spring when reproduction is not possible due to scarcity of nutritious food sources, thus host exploitation pattern is not well known. In order to understand the patterns of seasonal occurrence and how it relates to suitability of host plants in the spring, we evaluated the seeds of barley (Hordeum vulgare L.), sesame (Sesamum indicum L.), and black locust (Robinia pseudoacacia L.) as pre-season food sources for R. pedestris. A diet of soybean seed was also compared as a control. When nymphs fed sesame seeds only, R. pedestris never became third instars. Only 2.5 and 5% of R. pedestris fed on barley and barley + sesame, respectively, successfully became adults. Only when supplemented with soybean seeds could barley and sesame seeds support nymphal development and reproduction of R. pedestris. This indicates that neither barley nor sesame is adequate food sources for the development and the reproduction of R. pedestris even though they occur in those crop fields in spring and summer. However, seeds of black locust supported the complete development and reproduction of R. pedestris. Thus, black locust can be an additional leguminous host plant for R. pedestris during the period when suitable food sources are limited.

Evaluation of Aggregation Pheromone Trap as A Control Measure of Riptortus pedestris (Fabricius) in Soybean Field

M. Mahbubur Rahman,Eunmok Kim,Mohammad M. H. Bhuyain,Dongmok Kim,Un Taek Lim 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.04

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.

Flower model trap helps to reduce thrips infestation on red pepper in field

Bishwo P. Mainali,Eunmok Kim,Un Taek Lim 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

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.

Fabrication of functionalized halloysite nanotube blended ultrafiltration membranes for high flux and fouling resistance

Shinyun Park,Eunmok Yang,Hosik Park,Heechul Choi 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.5

Halloysite nanotubes (HNTs) were functionalized using 3-aminopropyltriethoxysilane (APTES) and incorporated into polyethersulfone (PES) membranes to improve the hydrophilicity of the membranes as well as the interfacial interaction between HNTs and the polymer matrix. The intrinsic properties, permeability, and selectivity of the prepared membranes were analyzed to evaluate the membrane performance. In addition, humic acid (HA) fouling experiments were conducted to measure the antifouling properties of the fabricated membranes. As HNTs and functionalized HNTs (f-HNTs) contents are increased, hydrophilicity and mechanical strength were enhanced, and membranes with f-HNTs showed further improved performance. The pure water flux of membranes with 2% HNTs and f-HNT was 7.5 times higher than that of a pristine PES membrane without a trade-off relation between the water flux and HA rejection. The membranes with f-HNTs showed the highest antifouling properties compared to membranes with HNTs because enhanced hydrophilicity played a key role in preventing accumulation of HA.