The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has been considered as a major thrips species after its invasion in 1993 in Korea although recently F. intonsa (Trybom) was found as a dominant species locally. To explain their asymmetrical abundance in the field, we hypothesized differential insecticide susceptibility of both thrips species as an underlying mechanism. Laboratory assays were conducted to know their susceptibility to different pesticides including chlorfenapyr, chlorpyrifos, thiamethoxam, spinosad, s-metolachlor, and metalaxyl by direct spray, residue, and oral ingestion. Results showed that both thrips species were highly susceptible to chlorfenapyr and mortality reached 100% within 12 hours in F. occidentalis in all the assays while 9 hours in F. intonsa in direct spray and residual assays. The LT50[h] values of tested insecticides were significantly lower than that of herbicide or fungicide regardless of exposure methods except metalaxyl from direct spray. The insecticides tested here differed considerably in species specific toxicity, and F. intonsa is generally more susceptible to the insecticides irrespective of exposure methods.

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.

꽈리허리노린재[Acanthocoris sordidus Thunberg (Hemiptera: Coreidae)]는 대만, 일본, 한국에 분포하며 고추, 가지 등의 가지과 식물의 주요 해충이다. 고추에서 꽈리허리노린재에 의한 주요 피해 부위를 알기 위해 작물내 분포를 조사하였다. 두 개의 무방제 시험포장에서 각각 8, 9월에 작물의 높이를 상부, 중부, 하부로 나누어 육안 조사한 결과 작물의 상부에서 노린재(알, 약충, 성충)의 76∼89%가 분포하였다. 고추 작물의 부위별 분포는 줄기에서 71∼85%로 가장 높았다. 발육단계별로는 알의 100%가 잎에서, 성충의 88%가 줄기에서 발견 되어 꽈리허리노린재 성충은 고추의 상단부 줄기에서 가장 많이 분포하고, 고추 과실에서는 거의 발견되지 않았다.

Frankliniella occidentalis (Pergande) and Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) are sympatric thrips species infesting crops including strawberry and pepper. Recently, F. intonsa was found as a dominant species locally even though F. occidentalis has been considered as a major species in Korea. We suggested interspecific competition as a underlying mechanism for the asymmetrical abundance. Effect of the competition on adult reproduction and longevity of the two thrips species was assessed in leaf cage and microtube arena, respectively. The number of reproduced progeny was reduced by 79% for F. occidentalis and only 43% for F. intonsa in competition condition. The mean longevity was also reduced greater in F. occidentalis (by 41%) than in F. intonsa (23%). Based on these results, it is probable that interference competition exists between the two species, and F. intonsa is better competitor than F. occidentalis. Therefore, interspecific competition might affect field occurrence pattern of the two thrips species.