RESISTANCE TEST OF THE WEEDS Asystasia gangetica, Eleusine indica AND Praxelis clematidea TO IPA GLYPHOSATE HERBICIDE INMATURE OIL PALM PLANTATIONS IN SOUTH LAMPUNG

Abstract

The long-term use of the same type of herbicide without replacement or rotation with other herbicides with different mode of action can trigger weed resistance to herbicides. Continuous use of glyphosate may lead to resistance, making weeds more difficult to control. This study aimed to test the resistance of the weeds A. gangetica, E. indica, and P. clematidea originating from oil palm plantations in South Lampung to glyphosate herbicide. The experimental design used was a factorial Randomized Complete Block Design (RCBD) with four replications. The first factor was the origin of the weeds and the second factor was the level of herbicide active ingredient dosage. The results showed that weeds previously exposed to glyphosate required a longer time to cause 50% weed mortality with LT50 (Median Lethal Time) values at a dose of 3,840 g/ha for A. gangetica, E. indica, and P. clematidea of 13.66, 2.56, and 1.48 days, respectively, while the non-exposed weeds were 9.36, 2.07, and 1.29 days, respectively. The exposed weeds of A. gangetica, E. indica, and P. clematidea required higher doses to cause 50% weed mortality with ED50 (Median Effective Dose) values of 518.96, 109.14, and 132.45 g/ha, respectively, while the non-exposed weeds were 264.54, 78.25, and 88.45 g/ha, respectively. The exposed weeds A. gangetica, E. indica, and P. clematidea were still classified as sensitive to IPA glyphosate herbicide with Resistance Ratio (RR) values of 1.96, 1.38, and 1.50, respectively.