Herbicide-resistantEchinochloa oryzoidesandE. phyllopogonin CaliforniaOryza sativafields

Abstract

Echinochloa oryzoides and E. phyllopogon have become the most serious weeds in California Oryza sativa since continuous flooding was used to suppress E. crus-galli. Continuous use of a limited number of available graminicides and an increasing number of control failures led to the investigation of herbicide resistance in E. oryzoides and E. phyllopogon. Greenhouse dose-response studies with postemergence (POST) applications of molinate, thiobencarb, fenoxaprop-ethyl, and bispyribac-sodium estimating GR50 (herbicide dose to inhibit growth by 50%) values suggested resistance to all herbicides in two E. phyllopogon accessions and to molinate and thiobencarb in one E. oryzoides accession when compared with susceptible E. phyllopogon and E. oryzoides controls, respectively. No resistance was detected in dose-response studies with propanil. Minimum and maximum ratios (R/S) of the GR50 values of resistant to susceptible E. phyllopogon plants (in two experiments involving two resistant accessions) were 7.8 and >13.3 for thiobencarb, 2.2 and 4.3 for molinate, 16.5 and 428.7 for fenoxaprop-ethyl, and 2.0 and 12.0 for bispyribac-sodium. Minimum and maximum E. oryzoides R/S ratios (average of two experiments) were 21.9 and 4.6 for thiobencarb and molinate, respectively. A resistant E. phyllopogon (one accession tested) and the susceptible control were killed by POST applications of glyphosate, glufosinate, and clomazone, and by a preemergence application of pendimethalin. Thus, the repeated use of the few available grass herbicides in the predominantly monocultured O. sativa of California has selected for herbicide resistance in E. oryzoides and E. phyllopogon. The introduction of herbicides with new mechanisms of action will be useful to manage herbicide-resistant E. oryzoides and E. phyllopogon. However, cross- and multiple resistance emphasize the need to integrate herbicide use with nonchemical means of weed management.

Effect of Nitrogen Sources and Weed Management Options on Weed Growth and Crop Yield of Transplant Aman Rice

“…In the large scale rice farming, herbicide based weed management has become viable option high costs of labor (Anwar et al, 2012;Singh et al, 2006). Although herbicides are more reliable tools to manage weeds but sole dependence on herbicide may develop resistant biotypes and negative impacts on environment (Fischer et al, 2000). Therefore, effective weed management needs an integrated approach such as appropriate land preparation, use weed seed free tillage instruments, vigorous cultivars, planting density, row spacing, water management, fertilizer management, manual or mechanical weeding and herbicides .…”

Cytochrome P450 CYP81A12 and CYP81A21 Are Associated with Resistance to Two Acetolactate Synthase Inhibitors in Echinochloa phyllopogon

“…E. phyllopogon is a noxious weed in rice (Oryza sativa) fields, and severe infestations cause large decreases in rice yield. In the late 1990s, R populations were found in the Sacramento Valley of California (Fischer et al, 2000a). R plants exhibited resistance to at least nine herbicides from seven different chemical groups: sulfonylurea, triazolopyrimidine, pyrimidinyl carboxy herbicides, aryloxyphenoxypropionate, thiocarbamate, quinclorac, and clomazone (Fischer et al, 2000b;Osuna et al, 2002;Ruiz-Santaella et al, 2006;Bakkali et al, 2007;Yasuor et al, 2009Yasuor et al, , 2010Yasuor et al, , 2012.…”

Study on the molecular mechanism of non-target-site resistance in several paddy weeds

“…米国カリフォルニア州で発見された除草剤抵抗性タイヌビ エ（Echinochloa phyllopogon = E. oryzicola）は，異なる作用 機構の除草剤に抵抗性を示す多剤抵抗性型であることが知ら れていた（Fischer et al 2000;Osuna et al 2002;Ruiz-Santaella et al 2006;Bakkali et al 2007;Yasuor et al 2008Yasuor et al , 2009 …”