선충포식성 곰팡이는 선충을 포획하기 위하여 다양하고 특수한 기관을 사용한다. 국내 성주지역의 참외 경작지 뿌리 주변의 토양에서 3차원 접착 고리를 형성하여 선충을 포획하는 곰팡이를 분리하였다. 곰팡이의 미세형태 구조를 관찰한 결과 분생포자병은 직립형으로 길이는 290~528 (342.8) μm으로 길었으며, 계란형의 30.5 × 20.3 μm 크기를 가진 1~3개의 분생포자를 형성하였다. 균주의 rDNA의 5.8 S 영역의 염기서열을 분석한 결과, Arthrobotrys속의 계통군에 속하였으며, 특히 Arthrobotrys sinensis와 99%의 유사성을 보였다. 형태적 특징과 분자생물학적 계통 분석을 바탕으로 본 균주는 A. sinensis로 확인되었으며, 이는 국내 미기록종으로 식물기생성선충의 생물학적 조절을 위한 하나의 자원이 될 수 있다.
The azuki bean weevil, Callosobruchus chinensis L., which is one of the notorious stored grain insect pest. Temperature-dependent development of C. chinensis. was examined at six temperatures of 14, 18, 22, 26, 30, and 34℃ on azuki bean and cowpea seeds. The total developmental time (egg to adult) decreased with increasing temperature from 14 to 34℃ on both seeds. However, total developmental time varied from 127.9 and 125.9 days at 14℃ to 19.9 and 20.3 days at 34℃ on azuki bean and cowpea seeds, respectively. The lower temperature thresholds (Tmin) were estimated to be 9.52℃ and 10.36℃, and the thermal constants (K) were 526.31 DD and 454.54 DD, on azuki bean and cowpea using general linear model, respectively, and the lower temperature thresholds and the thermal constants estimated by Ikemoto-Takai linear models were 10.63℃ and 10.79℃, and were 466.18 DD and 436.28 DD, on azuki bean and cowpea, respectively. These findings on thermal requirements and temperature thresholds can be used to predict the occurrence, number of generations and population dynamics of C. chinensis.
The development of resistant seeds to manage this pest is a big challenge for breeders. We investigated the oviposition preference and development of C. chinensis on two susceptible mungbean cultivars (Seonwha and Gyeongseon) and one previously reported resistant cultivar Jangan, compared to the susceptible cowpea, Yeonbun, by offering a multiple choice test and a no-choice test. Additional, insect stage wise development of C. chinensis was also examined at four temperatures (20, 25, 30 and 35℃). The both choice tests results showed that the cowpea is the most suitable seed host for oviposition. Total developmental time from egg to adult stage ranged from 27.01 to 38.2 days, and developmental time was shortest on the cowpea and longest on Jangan mungbean. However, no successful development of C. chinensis on Jangan mungbean occurred at all constant temperatures. Higher rate of adult emergence and longer adult longevity were found on cowpea and mungbean except Jangan mungbean. Results suggest, higher performance of C. chinensis on cowpea and mungbean might be governed by physical as well as chemical attributes of the seeds. Thus, Jangan mungbean could be stand as a resistant one against bruchids and it could be a resistant sources for successful breeding.
This study was conducted to evaluate resistance of 10 different cowpea cultivars which were introduced from the United States against two major root-knot nematodes, Meloidogyne arenaria and M. incognita, that affect greenhouse crop cultivation in Korea. The results showed that the resistance of the tested cultivars to the root-knot nematodes varied with the cultivar. Texas Cream 40 showed moderate resistance to M. arenaria whereas the other cultivars were susceptible. Purple Hull Pinkeye and Texas Pinkeye Purple Hull were found to be resistant to M. incognita, whereas Mississippi Silver showed moderate resistance and the other cultivars were susceptible. As the cultivars exhibit resistance to M. arenaria and M. incognita, such cultivars resistant to root-knot nematodes should be considered during the cultivation of cowpea as a green manure crop.