PJB-2020-89
Combination ratio affects synergistic activity of oil palm frond residue and S-metolachlor on goosegrass (Eleusine indica)
Tse Seng Chuah and Win Kent Lim
Abstract
Goosegrass (Eleusine indica), a troublesome weed, has been documented to evolve resistance to various groups of herbicides. Recent field study revealed that S-metolachlor in combination with oil palm frond residue (OFP) provided great suppression of herbicide-resistant biotype of goosegrass. However, study on interaction between OPF and S-metolachlor is still limited. Hence, combined phytotoxic effects of OFP and S-metolachlor were evaluated at the ratios of 50:50, 40:60, 30:70, 20:80 10:90 based on Additive Dose Model under glasshouse conditions. Pre-emergence application of S-metolachlor and OPF were able to reduce goosegrass emergence by 90% (ED90) at 3.5 t ha-1 and 148 g a.i. ha-1, respectively. The ED90 values of S-metolachlor were greatly reduced by approximately 72-92% when being incorporated with 1.0-1.4 t ha-1 of OPF at 50:50 and 40:60 ratios. However, the interaction turned antagonism as the rate of OPF was increased from 3.0 to 4.0 t ha-1 at the ratios of 30:70, 20:80 and 10:90. These results suggest that S-metolachlor in combination with OPF and applied as mulch could provide synergistic or antagonistic activity for goosegrass management depending on the ratio of oil palm frond residue combined with S-metolachlor
To Cite this article:
Chuah, T.S. and W.K. Lim. 2021. Combination ratio affects synergistic activity of oil palm frond residue and S-metolachlor on goosegrass (Eleusine indica). Pak. J. Bot., 53(4): DOI: http://dx.doi.org/10.30848/PJB2021-4(37)
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