This study was conducted to investigate the effect of attractant mixture on capture efficacy on Platypus koryoensis, an insect vector of oak wilt disease in Korea. We compared three treatments, such as Citral:EtOH(5:95), EtOH, and no attractant. In order to compare the attractants, Lindgren multi-funnel traps were installed in three oak forests in the Incheon Grand Park. A total of 18 traps was installed, and traps were replaced biweekly. A total of 236, 85, and 25 individuals were collected in Citral:EtOH, EtOH, and control, respectively. Although a mixture of Citral:EtOH seems more effective in attracting P. koryoensis, number of individuals of P. koryoensis caught by attractants was different according to study sites.

소나무재선충병은 1988년 부산 금정산에서 처음 발생하여 2017년 4월 기준 109시ㆍ군ㆍ구에서 99만본 이상 발생하였다. 소나무재선충 방제방법 중 가장 효과적인 방법은 나무주사로 약제 단가가 저렴해져 처리 면적은 점차 확대되고 있으나, 그 시기가 12월~2월로 극히 제한적이어서 처리시기 확대를 위해 10월 말부터 5월 중순까지 아바멕틴 유제와 에마멕틴벤조에이트 유제를 월 1회 나무주사하여 그 효과를 검정하였다. 그 결과, 10월 말~1월까지는 두 약제 모두 100% 방제효과를 보였고, 아바멕틴 유제는 2월(93.3%), 3월(86.7%), 4월(83.3%), 5월(80%) 방제효과를 나타내었다. 반면에 에마멕틴 벤조에이트 유제는 2월(100%), 3월(96.7%), 4월(96.7%), 5월(50%)로 4월까지 효과가 뛰어 났으나 5월에 급격히 방제가가 떨어졌다. 2월~5월까지 나무주사 후 약제 잔류량을 분석한 결과 아바멕틴 유제가 에마멕틴벤조에이트 유제 보다 약제 잔류량이 많았고 두 약제 모두 처리 시기가 늦을수록 약제 잔류량도 적게 나타났다. 각 시기별로 나무주사한 가지의 일부를 채취하여 소나무재선충을 접종한 결과 처리시기가 늦을수록 소나무재선충 증식량이 증가하는 경향을 보였다. 또한 처리방법을 현행방법과 주입병을 이용하여 각각 2월에 나무주사한 결과, 두 방법 모두 소나무재선충 예방효과, 약제 잔류량, 소나무재선충 증식량에는 차이가 없었다.

Avermectin produced by Streptomyces avermitilis is an anti-nematodal agent against the pine wood nematode Bursaphelenchus xylophilus. However, its potential usage is limited by its poor water solubility. For this reason, continuous efforts are underway to produce new derivatives that are more water soluble. Glycosylation is generally used to enhance the aqueous solubility and biological activity of natural compounds. Uridine diphosphate (UDP)-glycosyltransferase (BLC) from Bacillus licheniformis is involved in the biosynthesis of the bioactive compound by transferring UDP-activated sugar moieties to acceptor molecules. Here, the enzymatic glycosylation of avermectin was catalyzed by uridine diphosphate (UDP) glycosyltransferase from Bacillus licheniformis with various UDP-sugars. As a result, the following four avermectin B1a glycosides were produced: avermectin B1a 4’’-β-D-glucoside, avermectin B1a 4’’-β-D-galactoside, avermectin B1a 4’’-β-L-fucoside and avermectin B1a 4’’-β-2-deoxy-D-glucoside. The avermectin B1a glycosides were structurally analyzed based on HR-ESIMS, 1D and 2D nuclear magnetic resonance (NMR) spectra. The solubility of avermectin B1a4’’-β-D-glucoside and avermectin B1a4’’-β-D-galactoside in water are 49 and 21 times higher than that of avermectin B1a. Consistent with the improved water solubility of avermectin glycosides, the anti-nematodal effect of avermectin B1a4’’-β-D-glucoside was found to exhibit the highest activity,which was approximately 32 times greater than that of avermectin B1a, followed by avermectin B1a 4’’-β-2-deoxy-D-glucoside, avermectin B1a 4’’-β-L-fucoside, and avermectin B1a 4’’-β-D-galactoside. These results show that glycosylation of avermectinB1a effectively enhances itsin vitro anti-nematodal activity and that avermectin glycosides can be further applied for treating infestations of the pine wood nematode B. xylophilus.

Pine tree, a dominant species in the flora of Korea is the most beloved tree in Korea. However, recent outbreak of pine wilt disease caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus threatens the vegetation of Pinus species seriously. Furthermore, Pinus densiflora and P. thunbergii, the predominant species in Korea forest are highly susceptible to PWN. Therefore, there has been an urgent demand for the development of a new nematocidal compounds to control PWN, which spurred the national research for the development of new compounds. To find novel sources for nematocidal agents, we used various plant resources for the development. In addition to the foreign plant extracts themselves, we also used the extracts of endophytes composed of over 300 endophytic fungi and 1,000 endophytic bacteria from plants which was reported to contain nematocidal activity. Several extracts of endophytes and plant extracts contained strong nematocidal activity, and the resources are analyzed to identify the active nematocidal compounds. These integrated approach of finding effective nematocidal compounds from plants could be a novel way to elucidate the sources for brand-new nematocidal agents.

Pine trees are ecologically important in Korea. They are seriously imperiled by Pine wilt disease (PWD), by pine wood nematode (PWN, Bursaphelenchus xylophilus). Here, we isolated and characterized bacterial endophytes (BEs) from pine trees in Korea for biological control of PWN using BE metabolites. Using culture-dependent approach BE isolates were extracted from three tissues (needles, stems, and roots) of four pine species across 18 sampling sites in Korea. Bacterial isolates were characterized into 389 distinct isolates based on 16S rDNA sequencing. Ethyl acetate crude extracts (CEs) of bacterial liquid cultures were prepared using ethyl acetate and screened for nematicidal activity against PWN. BEs (1,622 isolates) were isolated; their taxonomic binning resulted in 215 operational taxonomic units (OTUs). Analysis of species richness and Shannon’s diversity of the three tissues revealed that BEs colonized the needles more than the stem and root tissues. Furthermore, based on nematicidal activity screening of 389 isolates, 44 BEs were identified, with two isolates exhibiting a significant inhibitory activity against PWN. Taken together, these data revealed numerous nematicidal BEs in pine trees, providing new insights that can serve as an effective and promising alternative approach to combat PWD.

Korean Oak Wilt (KOW), was first recorded in Gyeonggi Province in 2004, and since then has increased steadily in its occurrence and ecological and economic impacts. Platypus koryoensis vectors the symbiotic fungus Raffaelea quercus-mongolicae, which is the causative agent of KOW. KOW may be closely related to recent climate changes, which have allowed P. koryoensis to extend its distribution range in Korea. And it results in greater overlap with the susceptible host tree, Quercus mongolica throughout Korea. In this regard, changes in the climate suitability of P. koryoensis and Q. mongolica were predicted using CLIMEX model and the influences of other environmental factors such as elevation and the number of days with heat wave were also identified in this study.

호두는 경제적으로 중요한 유실수 중 하나이지만, 호두나무 포장 내에서 해충에 의한 피해 특성에 대한 정보는 매우 부족하다. 본 연구에서 는 복숭아명나방과 굴피가는나방에 의한 호두열매와 잎의 피해를 조사하였다. 2017년 충남 부여군에 위치한 포장에서 복숭아명나방에 의한 호두열매 피해율의 변화를 조사하였다. 또한 김천, 부여, 영동 및 화성의 포장 내에서 2종의 나방에 의한 호두열매 및 잎의 피해율을 조사하였다. 부여 포장 내 호두열매의 피해율은 시간이 흐름에 따라 지속적으로 증가하였고, 피해율은 늦여름에 가장 높았다. 호두열매의 최종 피해율은 부여, 김천 및 화성에서 각각 22.1%, 20.5%, 11.7%로 조사되었다. 굴피가는나방에 의한 잎 피해는 성목의 신초 가지(평균 11.2%)에 비해 묘목의 신초 가지(평균 58.5%)에서 더 높은 것으로 조사되었다. 본 연구 결과, 호두나무 포장 내에서 복숭아명나방과 굴피가는나방에 의한 열매와 잎 피해가 심각한 것으로 확인되었으며, 향후 이들에 대한 방제기술 개발이 필요할 것으로 판단된다.

Walnuts are economically important for forestry workers in recent, but there are few available data for insect pestsin walnut orchards. In 2017, walnut fruits and leaves were damaged by Conogethes punctiferalis and Acrocercops transecta,respectively. In late summer, damage rates by C. punctiferalis in Buyeo, Gimcheon, and Hwaseong were 22.1%, 20.5%,and 11.7%, respectively. According to A. transecta, damage rates in seedlings (58.5% in average) were higher than inolder trees (11.2% in average) irrespective of study locations.

The environmental friendly control of Platypus koryoensis (Murayama), a vector of oak wilt disease, was investigated using citral. To develop an effective attracted trap was performed in Yeoju (semi-field), Gunpo (field) and Cheongju (field). Using a ratio of four attractant (ethanol 100%, ethanol+citral (90:10, 95:5), ethanol+citral+hexane extract of Quercus mongolica (90:5:5)) was investigated attractive effects for the Platypus koryoensis. Most P. koryoensis were attracted to mixture of ethanol+citral (95:5). As a result, when using a citral in a certain concentration is would be able to develop an effective and environmental friendly control agent.

Pine wilt disease (PWD) is one of the most important forest tree diseases, especially in the East Asian countries of Japan, China, and Korea. The Japanese pine sawyer, Monochamus alternatus Hope, is the PWN vector for Japanese red pine and Japanese black pine while Monochamus saltuarius Gebler is the vector for Korean white pine. Various control methods, such as aerial pesticide applications, biological control using parasitoids and fumigant such as methyl bromide are used. But the PWD still has spread. Therefore, we were selected effective aerial insecticides. Susceptibility of M. saltuarius and M. alternatus adults were investigated using 9 insecticides which are available in the market in Korea. And then, we tested them to the Apis mellifera to vertify the environmental impact.

참나무시들음병 매개충인 광릉긴나무좀(Platypus koryoensis (Murayama))(Coleoptera: Platypodidae)의 에탄올과 신갈나무 수피 추출 물의 유인효과에 대하여 조사하였다. 유인트랩과 유인목 시험에서는 에탄올과 신갈나무 수피 추출물을 사용한 처리구가 대조구(무처리)보다 높 은 유인효과를 나타내었으나, 두 유인제 간의 유의성은 찾지 못하였다. 유인목의 직경별 침입공 수를 비교한 결과, 침입공 수는 직경이 클수록 증 가하였다. 유인목의 횡단면 상부와 하부 침입공 수를 비교한 결과, 상부보다 하부에 침입공이 많았고, 통계적으로 유의한 차이(p<0.05)를 나타내 었는데, 이는 직사광선에 의한 건조가 적은 하부가 매개충의 먹이가 되는 미생물 번식에 유리하기 때문이라고 추정되었다. 결과적으로 신갈나무 수피 추출물보다 비용 면에서 경제적인 에탄올이 광릉긴나무좀 모니터링 및 방제에 효율적으로 활용될 수 있을 것이며, 신갈나무 수피 추출물은 효율을 높일 수 있는 계속적인 연구의 필요성이 있다.