Occurrence and Distribution of ALS Inhibiting Herbicide Resistant Paddy Weeds by Using Soil Assay in Gyeongsangbuk-Do, Republic of Korea

Chae Min Han¹ Sang Kuk Kim^2,* Jong Hee Shin¹ Jin Won Kim³ Jung Bae Kwon¹ Yong Seub Shin¹

¹Division of Crops Research, Gyeongsangbuk-do Provincial Agricultural Research and Extension Services, Daegu 41404, Korea
²Bioresources Research Institute, Andong, 36614, Korea
³National Institute of Agricultural Sciences, RDA, Wanju 55365, Korea

Abstract

This study was conducted to investigate the occurrence and distribution of acetolactate synthase (ALS) inhibiting herbicide resistant weeds on paddy at 269 sites by soil sampling in Gyeongsangbuk-Do of Republic of Korea from November to April in 2017 and 2018. Pyriminobac-methyl and imazosulfuron were treated at 5 days after irrigation and herbicide resistant rate and occurrence area were estimated based on the number of survived weeds. The herbicide resistant rate and occurrence area were 39.7% and 39,555 ha, respectively, in Gyeongsangbuk-Do which was 2 to 2.5 times higher than those in 5 years ago. The herbicide resistant rate for Yeongju city and Cheongsong county was commonly highest at 66.7%, Cheongdo county was lowest at 5.6%. The herbicide resistant occurrence area for Sangju city had the largest at 6,090 ha, Cheongdo county was the lowest at 135 ha. The most dominant weed species was Monochoria vaginalis (26.9%), followed by Schoenoplectiella juncoides (14.5%), Lindernia dubia (12.1%), Echinochloa oryzicola (2.8%), Cyperus difformis (1.7%), and Blyxa aubertii (0.8%). Although there were differences in the number and occurrence rate of resistant weed species to and ALS inhibiting herbicide among areas in Gyeongsangbuk-Do province, M. vaginalis, S. juncoides, and L. dubia are more than 50% resistant to ALS inhibiting herbicides, intensive management is required.

Figures & Tables

Fig. 1. Map of 269 soil collection sites in Gyeongsangbuk-Do.