PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

Elaeis guineensis Jacq. (oil palm) is the principal export crop in Malaysia, accounting for a significant percentage of GDP. However, its production is hampered by various factors, in particular weeds. Weed control in Malaysian oil palm plantations predominantly relies on herbicides. The excessive herbicide use has driven the emergence of herbicide-resistant weed species in plantations. Repeated use of herbicides such as glyphosate, glufosinate-ammonium, metsulfuron-methyl, and paraquat has led to the prevalence of resistant weed biotypes. Herbicide resistance in weeds is a growing global concern, threatening food safety and security, agricultural sustainability, and the environment. While much of the focus has historically been on well-known resistant species, lesser-known weeds, particularly those infesting oil palms, also exhibit resistance, causing significant long-term impacts. However, research on these lesser-known species is limited, especially regarding their competitive effects, resistance status, and underlying resistance mechanisms. Focusing on these less-studied herbicide-resistant weed species is essential for effective crop management and the sustainability of oil palm cultivation. To address these challenges, this review explores the background of herbicide-resistant weeds in Malaysian oil palm plantations and examines integrated approaches for sustainable weed management. These strategies include cover cropping, targeted livestock grazing, and using herbicides in diverse modes of action. Integrating multiple management strategies, closely monitoring weed populations for early detection of resistance, and responding promptly to new detections are crucial steps in curbing the spread of herbicide-resistant weeds. Advances in molecular biology and precision agriculture practices will significantly enhance efforts in managing herbicide-resistant weeds.