Sulfonylurea resistance in Lindernia micrantha, an annual paddy weed in Japan

Resistance to sulfonylurea herbicides, including bensulfuron-methyl, pyrazosulfuron-ethyl, imazosulfuron and ethoxysulfuron, was discovered in naturally occurring populations of Lindernia micrantha D. Don in rice fields that had been treated with sulfonylurea-based herbicides for 3-7 consecutive years. The resistant biotype was approximately 80 approximate to 300 times more resistant than the susceptible one to the above four sulfonylurea herbicides. This is the second confirmed occurrence of herbicide resistance resulting from the use of sulfonylurea herbicides in Japan. Several herbicides with different modes of action, including pretilachlor, cafenstrole, bifenox, naproanilide, thiobencarb + simetryn + MCPB, MCPA-thioethyl + simetryn and cyhalofop-butyl + bentazone, effectively controlled the resistant biotype in pot trials.