This study was conducted to identify a present situation of sulfonylurea herbicide resistant (HR) weeds in paddy fields in Jeollabuk-do, Korea. Paddy soil samples were collected from 241 locations and imazosulfuron + pyriminobac-methyl was applied at 10 days after irrigation. Resistant rate and area were estimated based on the number of survived weeds. Area infested by HR weeds in Jeollabuk-do was estimated to 81,494 ha (70.5%). Nine herbicide resistant species were identified, and the resistance rate was in the order of Monochoria vaginalis (52.5%), Schoenoplectiella juncoides (46.3%), Echinochloa oryzicola (37.3%), Lindernia dubia (23.0%), Echinochloa crus-galli (8.4%), Cyperus difformis (5.4%), Ludwigia prostrata (4.8%), Sagittaria trifolia (1.5%), and Rotala indica (1.3%). HR M. vaginalis, S. juncoides, L. dubia, and E. oryzicola were surveyed from all cities in Jeollabuk-do. The E. crus-galli appeared in seven cities, C. difformis and L. prostrata were identified as the HR weeds in six cities. HR R. indica and S. trifolia were occurred in only two cities. Based on the result, HR weeds in Jeollabuk-do are sharply increased in terms of occurrence rate and area compared to 2012 and 2 or 3 weed species occurred in a region or field. Therefore, major 4 HR weeds, M. vaginalis, S. juncoides, E. oryzicola, and L. dubia should be managed in all regions in Jeollabuk-do and the resistance should be checked regularly for other 5 weed species.
Figures & Tables
Fig. 1. Location of the SAVEX15 site.