Resistance of Eleusine Indica (L.) Gaertn to Paraquat and Glyphosate in Oil Palm Plantations and Evaluation of Propaquizafop as an Alternative Control

Eleusine indica (L.) Gaertn is a grass weed commonly found in oil palm fields. This weed is mostly controlled on many plantations using herbicide applications, such as glyphosate and paraquat. Oil palm growers in West Kalimantan and Riau Provinces, Indonesia, are increasingly reporting a decline in the effectiveness of herbicides, raising concerns about the long-term sustainability of farming practices.

The study aimed to first confirm glyphosate and paraquat resistance levels in E. indica and, second, assess the effectiveness of propaquizafop herbicide on managing resistant weeds.

Seeds of E. indica suspected to be resistant were collected from West Kalimantan and Riau, while the susceptible biotype was collected from West Java. The method used was a split-plot design consisting of two factors with three replications. The resistance level test was conducted according to the whole plant pot test method. Herbicides were applied at seven dose levels: 0, 0.25, 0.5, 1, 2, 4, and 8 times the recommended dose of glyphosate (750 a.i. ha^-1), paraquat (400 a.i. ha^-1), and propaquizafop (100 a.i. ha^-1).

Experimental results showed that E. indica populations from Riau and West Kalimantan were identified as multiple resistant to glyphosate and paraquat. This result was evidenced by resistance index values of 2.58 and 4.36 for glyphosate, as well as 2.30 and 3.37 for paraquat. Resistant biotypes of E. indica were identified as susceptible to propaquizafop with a resistance index <2.

The findings of the research study indicate that propaquizafop has utilization as an alternative herbicide offers a promising solution to address the challenges posed by paraquat and glyphosate-resistant Eleusine indica.