Information on spatial distribution and peak occurrence is important for site and time specific pest management. So, we investigated seasonal occurrence and edge distribution of major soybean pests by visual count in six commercial fields located in Andong from July 16 to October 23 in 2015. We found a total of 19 species in 10 families. The major pest during vegetative stage was Medythia nigrobilineata (Motschulsky) while Riptortus pedestris (Fabricius) and Halyomorpha halys (Stal) showed peak occurrence during reproductive stage of soybean. Aphis glycines Matsumura was found throughout the season. Seasonal density of M. nigrobilineata was 0.20 and 0.38/plant in edge and interior without significance, respectively. The infestation of A. glycine was also found similar between edge and interior. Immatures of R. pedestris and H. halys distributed more in edge (0.21 and 0.36/plant) than interior (0.12 and 0.12/plant), respectively. The application of these informations on spatial distribution pattern of soybean pest was discussed.

A mycoinsecticide, Beauveria bassiana (strain GHA) marketed as BotaniGard® ES, was evaluated as a biological control agent against Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) a major soybean pest. It was tested on commercial soybean fields with one time spray of both high (1×109) and medium (1×108spore/ml) concentration and double spray of the medium concentration. Nymph population decreased in all treated fields regardless of dose and frequency of spray. But, adult and egg populations were not affected. Alive nymphs collected from the fields and kept in laboratory showed infection rate ranging 35-68% in treated plots while 0% in control plots. It also reduced damage on soybean pods and seeds by 17.7-21.2 and 18.0-22.5% compare to control, respectively. Additionally, B. bassiana reduced other pests found in soybean fields including brown marmorated stink bug Halyomorpha halys (Stål) and two striped leaf beetle Medythia nigrobilineata Motschulsky. Also there was no negative effect on the parasitism of released non-viable eggs of R. pedestris. These results suggest that, in field condition, one time spraying of B. bassiana in the concentration of 1×108spore/ml can help reducing crop damage as well as R. pedestris nymph population.

이산화염소(ClO2) 훈증제는 살충효과를 나타낸다. 그러나 일부 곤충은 이산화염소에 대해 회피행동을 보여, 이 훈증제에 대한 방제효율을 크게 떨어뜨리고 있다. 본 연구는 이를 해결하기 위해 이산화염소 처리에 열처리를 추가하여 곤충의 이산화염소에 대한 회피행동을 줄여 살충효과를 극대화하는 전략을 세웠다. 이산화염소 훈증 처리는 거짓쌀도둑거저리(Tribolium castaneum)에 대해 살충효과를 주었으며, 시험 곤충이 노출된 조건에서 12 시간 처리할 때 유충에 대해서 383.67 ppm (153.63 - 955.78 ppm: 95% 신뢰구간), 성충에 대해서 397.75 ppm (354.46 - 446.13 ppm: 95% 신뢰구간)의 반수치사농도를 나타냈다. 그러나 먹이인 밀가루를 충분히 제공한 상태에서 이산화염소를 처리하면, 처리 약제에 반응하여 시험 곤충이 먹이 속으로 들어가는 회피행동을 보이면서 방제효과는 크게 낮아졌다. Y 튜브를 이용한 이 곤충의 먹이 선호성 행동을 분석한 결과 거짓쌀도둑거저리 성충은 이산화염소가 처리된 먹이를 회피하는 행동을 보였다. 그러나 촉각을 제거한 경우 이러한 회피행동은 둔화되었다. 거짓쌀도둑거저리에 6 시간 동안 46℃ 열처리를 하면 살충효과는 10% 이하로 낮지만, 처리된 성충들이 먹이 밖으로 나와 있는 것을 관찰하였다. 반면 400 ppm의 이산화염소를 단독으로 6 시간 처리한 결과 회피행동에 따라 전혀 살충효과를 보이지 않았다. 그러나 46℃ 열처리와 400 ppm의 이산화염소를 병행하여 6 시간 처리한 결과 살충효과는 95%로 크게 증가하였다. 따라서 열처리는 거짓쌀도둑거저리의 이산화염소에 대한 회피행동을 억제하여 살충효과를 증가시켰다.

Riptortus pedestris (F.) (Hemiptera: Alydidae) is an important pest of soybeans in Korea and Japan. A synthetic aggregation pheromone trap has been commercialized and used in soybean fields in Korea for both monitoring and mass-capture of this bug. As the trap’s efficacy in reducing the pest population or crop damage is unknown, in this study we evaluated the aggregation pheromone trap in experimental soybean fields located in Andong National University. Two treatments, one with traps deployed for the entire cultivation period and one with no traps, were tested in six small experimental fields. The total numbers of R. pedestris (in all life stages) in soybean field were not significantly different between the treatments until August. But, in presence of pheromone, the pest’s abundance increased significantly in September and October. Relative to the size of the bug population in the field, trap catch rate was low during the fall (when bug density was highest) and high in early summer when the field population was very low. Placement of aggregation traps in plots caused pod and seed damage from R. pedestris to increase 2.7 and 2.2 times compared to the control. In conclusion, R. pedestris populations increased significantly during the fall in the presence of the aggregation pheromone trap, which should therefore be used with great caution whether as a control measure or as a monitoring tool.

톱다리개미허리노린재[Riptortus pedestris (Fabricius) (Hemiptera: Alydidae)]의 방제를 위해서 집합페로몬트랩이 일부 사용되고 있으나 실제 방제 효과가 있는지에 대한 연구는 드믄 편이다. 2013년 안동지역 콩 경작지에서 집합페로몬트랩의 설치시기에 따른 노린재 방제 효과에 대한 연구 중 트랩설치가 콩의 재배 후반부에 톱다리개미허리노린재 밀도를 오히려 상승시키는 것을 발견하고, 이를 실험적으로 확인하기 위해 안동대학교 시험포에서 추가 연구를 수행하였다. 본 발표에서는 그 결과를 보고하고 토론하고자 한다.

Riptortus pedestris is an important soybean pest in Korea and Japan. Aggregation pheromone traps were evaluated in 12 soybean fields in Andong using three treatments of trap installation, i.e., installation for whole cultivation period, installation up to September, and no installation. The number of R. pedestris (in all life stages) were not significantly different among the treatments until October, but its abundance significantly increased at mid October in the fields where traps were installed. Trap catch of R. pedestris was relatively higher in August while bug population was low in the fields. However, in fall, R. pedestris populations become abundant in the fields while trap catch was low. There was no significant difference in parasitism as well as seed and pod damage among the treatments. In conclusion, aggregation pheromone trap should’nt be used as control measure, but can be used as a monitoring tool of R. pedestris population up to August in soybean field.