Efficacy of herbicides and reductant at different levels to control invasive tall reed (Phragmites karka) in oil palm plantations

Abstract

Controlling Phragmites karka, a highly invasive weed, is critical for peat areas since this species is a significantand hard-to control weed in oil palm plantations. Herbicides are one of the most effective and efficient tools for controlling P. karka, and their use is increasing due to their ability to provide rapid and long-term results. However, herbicides must be applied responsibly and carefully to minimize any environmental impacts. The study included an evaluation of the effectiveness of several combinations of herbicides on P. karka in an oil palm plantation and a comparison of their efficiency and cost. Results showed that combination of 1.8 L/ha glyphosate, 0.045 L/ha topramezone and 0.3 L/ha reductant Y (G7) has a promising result in controlling P. karka (weed mortality of 97% until 8 WAA and 12% regrowth until 12 WAA) and was more cost-effective compared to estate practice, reducing cost up to 0.43% per hectare because of the use of pesticide reductant. The use of reductant technology in this treatment also showed an effectiveness in reducing application frequency. This study demonstrates that herbicides can effectively and efficiently control P. karka in oil palm plantations, especially in peat land. Reductant can be one of the solutions to reduce the use of herbicides without lessening the efficacy, affordably, and sustainably.