• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.116-118
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• 1984

This study was carried out to know the percentage of parasitism and host preference of Haplogonatopus atratus (Dryinidae) in the nymphs of small brown planthopper. The percentages of parasitism in the nymphal stage of planthopper at each generation were $19.2\%$ for overwinterd generation, $10.8\%$ for the 1st generation on barley field and $21.5\%$ for the 2nd generation on paddy field, respectively. The percents of the parasitism for the respective instars were $78.2\%$(3rd), $17.5\%$(End), and $4.2\%$(4th) when various developmental stages of the planthopper had been caged together. No parasitized individual was found for the instars of the 1st, the 5th and the adult.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.165-169
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• 1990

A study was carried out to investigate some biological characteristics of Pseudogonatopus nudas, a nymphal parasitoid of the whitebacked planthopper (WBPH) under laboratory conditions (26-$28^{\circ}C$). Developmental periods of eggs, larva, prepupa and pupa were 2.5, 7.8, 2.7, and 14.2 days in average, respectively. Total developmental period from egg to adult emergence was average of 27.2 days. More than 83.5% of the wasps emerged in the morning between 6 and 10 o'clock, while very few emerged in the afternoon. The average longevity of female and male were 11.8 and 3.4 days when honey and WBPH nymphs were supplied as food. female laid an average of 25.3 eggs and the oviposition period was 5.4 days. The parasitoid seemed to prefer the 3rd instar nymphas as the host for oviposition with 68.8%, followed by the 2nd (19.6%), 4th (11.05) and 5th instar (0.6%). And no parasitism was recorded from the 1st instar nymphs and in adults.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.253-259
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• 1985

This paper presents a natural enemy complex of plant and leafhoppers in rice plants and a relationship between the host insects and their natural enemies. Feeding preference of major paddy spiders have been tested. To date, 32 species of natural enemies of plant and leafhoppers have been recorded, including 30 species of parasites and predators (15 parasitoids, 14 predators and nematode) and 2 species of insect pathogens. Some of species have shown great potential for controlling plant-leafhoppers populations; parasites, Anagrus nr. flaveolus, Gonatocerus sp., Haplogonatopus atratus and paddy spiders. Pirata subpiraticus and Gnathonarium dentatum. Plant and leafhoppers-natural enemy relationship have been observed in different developmental stages of the host insects. Pirata sub-piraticus is the most active to searching the host insects and also prefered nymphs to adults.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.321-327
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• 1995

This study was conducted to determine the winter ecology of the small brown planthopper (SBPH), laodelphax striatellus Fallen, in Milyang, east Kyungsangnamdo province. The age distribution in the overwintering SBPH population varied according to collection dates. In early December, the population distribution was 60% 4th instar, 30% 3rd instar, 6% 5th instar, 3.4% 2nd instar with very few adults and 1st instar. In early March 5th instars had the highest propotion (47-50%) with 4th instar 44-46%. In early April the adult population was 75-81% of the population. The averaged nymphal instar converted the age distribution of he overwintering SBPH in to the into the numerical values tended to increase continuously. However, there were some differences in the averaged nymphal instar of overwintering SBPH annually and these differences resulted from different age distribution of the overwintering SBPH due to different annual temperature fluctuations during overwitering periods. The weight of the overwintering SBPH increased continuously during overwintering periods. The collection density of the overwintering SBPH population was significantly higher on the levee than in the barley field. Percent nymphal parasitism by haplogonatopus atratus in the overwintering SBPH population averaged about 21% regardless of overwintering years.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.497-501
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• 2014

The small brown planthopper, Laodelphax striatellus (Fall$\acute{e}$n) (SBPH) is one of the important rice pests in Korea, which transmits rice stripe virus (RSV) to rice. This pest is an indigenous species in Korea and has also known to migrate from China to the western coastal areas of Korea. This study was conducted to investigate the wing morphs of SBPH and its parasitism rate of Haplogonatopus atratus Esaki et Hashimoto in Korea. In 2014, SBPH were collected in April and July from 16 sites throughout South Korea and their wing morphs and parasitism rates were measured under the microscope. Percentage of brachypterous male in July was significantly declined compared to that in April, while that of brachypterous female did not change. A positive relationship was found between latitude and percentage of brachypterous adults in April. Parasitism rate of both nymphs and adults were higher in April than July. In addition, nymphal parasitism rate was generally higher in western coastal areas.

• Parasites, Hosts and Diseases
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• v.36 no.1
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• pp.63-66
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• 1998

The first case of tick bite by Ixones persulcatus in Korea is reported. The lick was found on the skin of right lower axilla region of a 60-year-old woman.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.423-432
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• 2022

The mass-rearing system for Neodryinus typhlocybae as a biological control agent of Metcalfa pruinosa was established. Depending on the density of host nymphs and plants, the average number of cocoons produced by the parasitoids was 5-8 and 70-150 cocoons per leaf and sapling of mulberry, respectively. There is a significant difference in cocoon length between females (6.10-6.46mm) and males (4.20-4.62mm). Sex determination of cocoons before emergence will be helpful for efficiently releasing this parasitoid in fields. The parasitic rate of N. typhlocybae at the semi-field condition was on average 13-17%. The release number of this parasitoid did not affect parasitism. Nevertheless, the population growth rate of M. pruinosa was reduced by increasing the release number of N. typhlocybae. The parasitoid offspring's sex and bivoltine were influenced by the host age. On young host nymphs, the bivoltine portion of parasitoid increased. When parasitized on 4^th or 5^th nymphs, the offspring's female ratio of N. typhlocybae increased. This result may be useful for potentially controlling mass rearing production of parasitoid.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.439-452
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• 2018

This study was carried out to establish of environment-friendly control system and to survey the occurrence status of Ricania shanthungensis in Jeonnam province from 2016 to 2017. R. shanthungensis occurred at 1,344 ha in 61 towns of 15 cities in Gwangju and Jeonnam province. At four sites in the stationary area, the densities of eggmass and pupae were lower in 2017 than in 2016, the hatching rate decreased, and the first hatching time, emergence of adults, and the start of spawning tended to be slower. Telenomus sp., an egg parasitoid of R. shanthungensis, was found in most areas. Sunchon had the highest rate of 46.1%, followed by Muan 40.6, Goksung 29.2, Gurye 25.8, and Gwangju 17, respectively. The optimum spraying time for the control of R. shanthungensis was early March. The spraying material and the dilution multiples are 10 times of the machine oil at environmental friendly cultivation and 500 times of the chlorpriphosphate wp. at normal cultivation. When sprayed these materials, 95% of egg prohibited to hatch. There was more than 80% of the insecticidal effects on the organic materials of the machine oil emulsion, the Sophora root extrect + microbial extract agent, and the castor emulsion. For adults, Sophora root extrect + microbial extract, neem extract, and machine oil were better. Four kinds of chemical pesticides such as dinotefuran wp were effective for nymph and adult control. We have developed an adult catching device using the most preferred daylight color and behavioral habits of R. shanthungensis. The capture device consisted of two daylight compact lamps (30W and 20W), a yellow plate, and a catcher using water, and caught about 700 individuals a day. Based on the above results, we have established a system for controlling and life cycle of R. shanthungensis in Jeonnam province.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.437-448
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• 2013

Hemipteran bugs, which were previously considered as secondary pests, have currently become important pests of numerous crops. Among them, Riptortus pedestris (Fabricius) is a major species that occurs in Korea, Japan, China, and South Asian countries. Riptortus pedestris infests leguminous crops like soybean, vetches, and red clover; fruit trees like persimmon and yuju; and grains like barley, foxtail millet, broomcorn, and sorghum. Riptortus pedestris causes the greatest damage to soybean, as it is the most suitable host for the bug. Feeding damage during pod formation significantly reduces the yield of soybean. Currently, 17 insecticides, including diazinon and etofenprox, are registered for the control of hemipteran bugs in Korea, and growers apply insecticides two to three times on a regular basis. Aggregation pheromone traps are widely used as a monitoring tool and partial control measure. The aggregation pheromone of R. pedestris attracts conspecific adults and nymphs and is used for food exploitation rather than sexual attraction. In addition, the pheromone serves as a kairomone for egg parasitoids such as Gryon japonicum (Ashmead) and Ooencyrtus nezarae Ishii. As a new method of pest management, nonviable host eggs were included in the pheromone trap to catch R. pedestris and propagate parasitoids. As a part of cultural practices, resistant soybean varieties with specific color and size of pod and control of flowering time through the alteration of planting date can be used. For the effective management of R. pedestris in the near future, development of cultural practices that can support natural control factors and the use of multiple control tactics are needed.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.319-325
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• 2009

Woolly apple aphid, Eriosoma lanigerum, overwintered as adult or nymph stage on rootstocks, and crown- and root sucker in the soil. In an un sprayed apple orchard, the number of E. lanigerum colony started to increase from mid-April, showed the 1st peak between late June and early July, thereafter decreased followed by the 2nd peak in late July, and then again peaked in late September as the size in the 1st peak. In this orchard, the number of E. lanigerum colonies per tree did not exceed 3.5 colonies during the peak occurrence period, and was maintained around 2 colonies throughout seasons. In all seasons, parasitism of Aphelinus mali on E. lanigerum was much lower on root colonies than on aerial colonies that located on shoots and tree trunks above the ground. The parasitism of E. lanigerum was high in most orchards examined, showing parasitism of > 70% in maximum in most cases. In the laboratory bioassay for the mortality effects of several insecticides on E. lanigerum, fenitrothion, dichlorphos, machine oil, methidathion, thiacloprid, and imidacloprid showed 97.8, 96.8, 95.4, 91.5, 26.7, and 7.8% morality, respectively. Also, the adult emergence rates from A. mali mummies were 51.2, 72.6, 14.2, 3.5, 72.2, and 85.4% in the treatment of the above insecticides, respectively. Insecticides belong to neonicotinoid, which are newly developed to control aphids, showed low mortality against E. lanigerum. Fenitrothion and dichlorphos were effective on E. lanigerum control and had a low toxic to A. mali. Consequently, the insecticides should be useful in integrated pest management system for E. lanigerum in apple orchards.