The level of wild oat resistance to ACC-ase inhibitors in South-Eastern Poland

Abstract

In the years 2003-2004 two experiments: laboratory and field, were carried out to detect the level of wild oat herbicide resistance. Weeds were collected from fields in south-eastern Poland, on the basis of survey conducted between farmers who have problems with wild oat herbicidal fighting. Two herbicides were tested: fenoxaprop- P-ethyl and diclofop methyl, both ACC-ase inhibitors. The laboratory test was established by modified Letouze et al. (1997) method. After 6-day growth on each herbicide water solution, the number of alive wild oat seedlings was assesed. In the field experiment plants in 3-5 leaf stage were sprayed with field dose of each herbicide. Two weeks after spraying the percentage of plants damage and in July the percentage of flowering plants were assesed. The wild oat plants that survive in laboratory test in ≥50% and plants that flowered in ≥50% in field conditions were recognized as resistant. On that basis wild oat resistace to fenoxaprop-P-ethyl and to diclofop methyl was stated on 17% and 28% fields from overall number of 18 fields, respectively.