Initial report of glufosinate and paraquat multiple resistance that evolved in a biotype of goosegrass (Eleusine indica) in Malaysia.

Field and glasshouse studies have confirmed the presence of a glufosinate- and paraquat-resistant goosegrass biotype that has infested a bitter gourd field in Air Kuning, Perak, Malaysia. Glufosinate and paraquat had been applied at least six times per year to the affected fields (originally a rubber plantation) for more than four consecutive years. Paraquat had been used since 1970 for weed control in the rubber plantation. An on-site field trial revealed that the control of the goosegrass plants, measuring 20–35 cm in height, ranged from 20 to 35% 3 weeks after being treated with each herbicide at twice the recommended rate. Dose–response tests were conducted in the glasshouse, using seedlings at the three-to-four-leaf stage that had been obtained from the plants that had received repeated exposure to these herbicides and a biotype with no history of any herbicide resistance. The comparison of the GR50 (the herbicide rate that is required to reduce the shoot fresh weight by 50%) of the seedlings indicated that the resistant biotype of goosegrass is 3.4-fold and 3.6-fold more resistant than the susceptible biotype following treatment with glufosinate and paraquat, respectively. This study has demonstrated the world's first field-evolved instance of multiple resistance in goosegrass to two non-selective herbicides, glufosinate and paraquat.