• Korean journal of applied entomology
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• v.48 no.1
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• pp.67-72
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• 2009

The kairomonal activity of the aggregation pheromones of Riptortus clavatus for the egg parasitoid, Gryon japonicum, were investigated in soybean field. The parasitism rate of G. japonicum gradually decreased when the distances between pheromone traps and egg sites were increased from 0 to 15 m. The active distance of pheromone source for parasitoid attraction was estimated to be ca. 15 m. Under field conditions, the parasitoid wasp population peaked during the late August and early September, and the parasitism rate increased when the number of pheromone traps was increased from one to three per $165\;m^2$. However, insecticide-treated plots, the level of parasitism recorded is relatively low. Sex ratios in field populations of G. japonicum were female-biased.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.87-92
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• 2017

The Samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Platygasteridae) is recognized as a solitary parasitoid on eggs of the stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an economic pest causing severe damage to fruits, in South Korea. The wasp appears to be a potential biological agent of the pest. In addition, T. itoi Ryu and T. nigripedius (Nakagawa) were found to parasitize eggs of Eurydema gebleri Kolenati and Dolycoris baccarum Linnaeus, respectively. Diagnostic characters and photographs are provided for identification, and host records of Korean Trissolcus species are also given.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.91-98
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• 2021

The populations of Riptortus pedestris (Fabricius) cause serious economic damages in local apple orchards. However, there was no study to manage its populations with environment friendly tactics. Thus, this study was conducted to analyze its attraction effects of one of R. pedestris aggregation pheromone compounds, (E)-2-hexenyl (Z)-3hexenoate (E2HZ3H), to its parasitoids, Ooencyrtus nezarae (Ishii) and Gryon japonicum (Ashmead). This compound did not increase the number of these two parasitoids and change its spatial distribution. However, this compound could attract two parasitoids within limited distance. These results indicates that one compound of R. pedestris aggregation pheromone, E2HZ3H, could be a good candidate to manage R. pedestris populations in conditions that its populations locally occurs in apple orchards.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.281-286
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• 2007

Two hymenopteran egg parasitoid species, Gryon japonicum (Ashmead) (Scelionidae) and Ooencyrtus nezarae Ishii (Encyrtidae), were emerged from eggs of bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae). The former parasitoid is first recorded in Korea. Brief morphological and biological characteristics, and parasitism on R. clavatus eggs are described.

• 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.