Two species in Monochamus (Coleoptera: Cerambycidae) are wellknown vector species of the pine wood nematode (PWN) in South Korea. In 2018, the surveys using sentinel logs with two Monochamus species larvae were made from early June to last September in Pinus densiflora forests of Pohang city, South Korea. The experiments were repeated 10 times in order to investigate parasitism patterns of the larval parasitoids of M. saltuarius and M. alternatus. Three plots were chose at interval distance of 20 m (0 m, 20 m, 40 m) from the edge to the center of the forests (i.e. forest depths) in one damage area of the pine wilt disease for each of three different locations. For each time of the exposure ten sentinel logs were hung along the tree heights (i.e. sentinel logs positions) (height: 0 m, 1.8 m, 3.6 m, 5.4 m, 7.2 m). As the results of the surveys six larval parasitoids in total were identified, and most abundant parasitoids were Spathius verustus and Cynopterus flavator. Analyses showed that the parasitism rate on larvae of two Monochamus species was not affected according to forest depth, but the parasitism rate was the highest in the third plot. Also the parasitism rate was the highest at 5.4 m height of a tree. Lastly, parasitisms rate on M. alternatus was higher than that of M. saltuarius.

During the last few decades, we have faced problems caused by some invasive forest pests such as the black locust gall midge, spotted lanternfly, citrus flatid planthopper, pine wood nematode, etc. As for the pine wood nematode, it is originated from the US and found two insect vectors which previously were not considered as insect pests at all in Korea. Now those two Monochamus cerambycids are nothing but insect pests to be controlled in order to slow down the spread of the pine wood nematode. Here we introduce the results of the surveys seeking out parasitoids which can be used for biological controls against those pests. In addition we also make a suggestion to keep our efforts to utilize those beneficial insects as eco-friendly control measures, not simply depending on physical or chemical methods.

Monochamus saltuarius Gebler (Coleoptera: Cerambycidae) is a well-known as vector species of the pine wood nematode (PWN) in the northern areas of South Korea. In 2017, larval parasitoids of M. saltuarius and their parasitism patterns were investigated in Pinus koraiensis forests with consideration of sentinel logs positions (height: 0 m vs. 1.8 m), distances from the edge to the center of the forest (0, 20, 40, 60, 80m), and damage degrees of the pine wilt disease (infested area, buffer area, and uninfested area). In total six of larval parasitoids were collected: Spathius verustus, Sclerodermus harmandi, Cynopterus flavator, Heydenia testacea, Heydenia sp., Braconidae sp. The parasitism rate to larvae of M. saltuarius larvae was not affected by sentinel log positions. However, the parasitism rate was significantly higher in infested areas compared to the buffer and uninfested areas. In the infested area, the parasitism rate was increased with distance from forest edges.

Chinese longhorned beetle (CLB; Anoplophora chinensis) and Asian longhorned beetle (ALB; A. glabripennis) were accidentally introduced into the US from the Asia back in 90s’ and have been causing economic damage on hardwood species in the US. An international cooperative team made field surveys in Korea to find parasitoids of CLB and ALB using sentinel logs that were infested with eggs of the two cerambycids.. As a result, two parasitic wasps of Anopolophora species were newly recognised from Korea: Aprostocetus anoplophorae Delvare (Eulophidae) as an egg parasitoid of CLB and Leluthia honshuensis Belokobylskij & Maeto (Braconidae) as a larval parasitoid of ALB. Identification was made using both morphological and molecular data. Morphological information was provided along with images of developmental stages and adults.

Conservation biological control (CBC) is one of the pest management tactics based on protecting and maintaining natural enemies that already exist in the crop environment. Among many appropriate practices to control pests, CBC has been considered as a sustainable means and a less expensive alternatives to chemicals. It contains an introduction of non-crop plants as shelter habitat for providing natural enemies with food sources, overwintering or refuges shelters. As a small scale experiment of CBC, we tried to intercrop six kinds of floral plants (buckwheat, red clover, Agastache rugosa, Chrysanthemum indicum, Allium tuberosum, Lythrum anceps) with napa cabbage in order to attract some natural enemies, especially parasitic wasps that could be fed on them in the cabbage fields, which is a novel way for conservation of natural enemies, but none showed significant result. For the development of integrated pest management system by harmonizing biological and chemical control, we carried out evaluating toxicity of 30 pesticides to parasitoids and investigating effectiveness of traps. With leaf dipping method for adult and body dipping method for cocoons, 12 pesticides showed under 30% of toxicity being selected as safer by IOBC. Using sex-pheromone traps for attracting lepidopteran pests showed that DBM, CAW and CL occurred less than untreated fields; 67.5%, 70.6% and 44.0%, respectively. Also, yellow sticky traps could reduce some pests; 52% for flea beetle, 62% for cabbage sawfly and 41% for Phaedon brassicae. These results are expected to give basic information to develop conservation biological control of DBM with indigenous parasitoids in the cabbage fields on a large scale in the future. Before developing and distributing a promising pest control method, we should consider whether it can be compatible with other agricultural practices or various situations around fields.