Abstract
Cyhalofop-butyl and penoxsulam, known for respective acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor, have been widely using as a post-emergence foliar application for many years in wet-seeded rice field in Korea. Since 2009, control of Echinochloa oryzoides with cyhalofop-butyl and penoxsulam was no longer satisfactory. Greenhouse and experiment in rice field were conducted to confirm E. oryzoides resistance to ACCase and ALS inhibitors and to compare herbicide treatments for control of the resistant E. oryzoides to ACCase and ALS inhibitors. Three resistant E. oryzoides to ACCase and ALS inhibitors accessions were tested for levels of resistance to cyhalofop-butyl and penoxsulam, base on survival rate. Iksan and Kimje accessions were not any affected to the survival by treatment with recommended doses of two herbicides tested. Buan accession displayed an intermediate response of 62 and 72% survival at recommended doses of cyhalofop-butyl and penoxsulam, respectively. Survival rates to herbicides mixed with ACCase and ALS inhibitors at 3.5 leaf stage of E. oryzoides was over 80%. Benzobicyclon+fentrazamide+bensulfuron SC, benzobicyclon+mefenacet+bensulfuron SC, benzobicyclone +cafenstrole+pyrazosulfuron-ethyl GR controlled effectively by 2 leaf stage of resistant E. oryzoides to ACCase and ALS inhibitors. In the field experiment, single treatment of benzobicyclon+ fentrazamide+bensulfuron SC and benzobicyclon+mefenacet+bensulfuron SC failed to control E. oryzoides, but squential treatment of benzobicyclon+thiobencarb SE and benzobicyclon+ mefenacet+ bensulfuron SC controlled effectively it in rice infant seedling culture with machine. Our results suggest that resistant E. oryzoides to ACCase and ALS inhibitors had not developed multiple resistance to herbicides with different modes of action. In particular, cafenstrole, fentrazamide, mefenacet were effective control measures.
ACCase 저해해제인 cyhalofop-butyl과 ALS 저해제인 penoxsulam은 한국의 직파재배 논에서 수년 동안 경엽 처리용으로 사용되어지고 있다. 그러나 2009년 이후 익산, 김제, 부안에서 이들 제초제를 사용한 벼 직파재배 논에서 강피 약효에 대한 민원이 증가하고 있다. ACCase 및 ALS 저해제 저항성으로 추정되는 강피를 3개 지역에서 수집하여 온실조건에서 cyhalofop-butyl과 penoxsulam에 대한 저항성 정도를 검증하였다. 익산과 김제의 수집종은 cyhalofopbutyl과 penoxsulam의 추천량에서 완전 생존하였으며, 부안 수집종은 약 60% 생존하였다. 온실조건에서 화본과 잡초인 피를 방제를 위한 ACCase 및 ALS 저해제들이 혼합된 제초제들을 강피 3.5엽기에 처리한 결과 무처리 대비 생존율은 80% 이상으로 나타났다. 파종 및 이앙전 처리제들인 oxadiazon EC, pyrazolate SC, pretilachlor EC, benzobicyclon+thiobencarb SE들은 강피 0.5엽기에서 효과적이었으며, benzobicyclon+fentrazamide+bensulfuron SC, benzobicyclon+ mefenacet+bensulfuron SC 그리고 benzobicyclone+cafenstrole+pyrazosulfuron-ethyl GR은 강피 2엽기까지 효과적으로 방제하였다. 포장실험에서 benzobicyclon+fentrazamide+bensulfuronSC과 benzobicyclon+mefenacet+bensulfuron SC의 단일처리에서는 저항성 강피의 방제에 실패하였으나, benzobicyclon+thiobencarb SE와 benzobicyclon+mefenacet+bensulfuron SC의 체계처리는 강피를 효과적으로 방제하였다. 따라서 강피의 익산, 김제 수집종은 cyhalofopbutyl과 penoxsulam애 대하여 강한 저항성을 보였으나, 작용기작이 다른 cafenstrole, fentrazamide, mefenacet에 의해 2엽기 이내에는 효과적으로 방제되었다.
