Effects of selected pre-emergence herbicide-treated oil palm residues on goosegrass emergence and growth

Abstract

Background

Goosegrass, one of the problematic weeds in the world. Various herbicides have been widely employed for goosegrass control. However, heavy reliance upon the herbicides has led to the evolution of herbicide-resistant biotypes of goosegrass. Diversified approach is needed for sustainable management of goosegrass.

Objective

Evaluate the phytotoxicity of selected preemergence herbicide-treated oil palm residue powders on goosegrass emergence and growth.

Methods

A glasshouse experiment was arranged as complete randomized design with five replications. The oil palm residue powders; leaflet (OPL), rachis (OPR) or frond (OPF, leaflet + rachis) were treated with pre-emergence herbicides, viz S-metolachlor, oxyfluorfen or thiobencarb at their respective ED50 rates (rate that gives 50% inhibition) and applied as mulches. The analyzed variables were emergence and shoot fresh weight of goosegrass seedlings.

Results

The ED97 value (rate that causes 97% inhibition) of S-metolachlor for growth of goosegrass was reduced by more than 90% when being mixed with the oil palm residue powders. Similarly, the ED97 value of thiobencarb was reduced by 90% when goosegrass was treated with thiobencarb–treated OPF powders. By contrast, the oxyfluorfen-treated oil palm residue powders and thiobencarb-treated OPL or OPR powders provided lower inhibitory effect on the goosegrass.

Conclusions

Oil palm residues of leaflets, rachis and fronds have potential to reduce rate of preemergence herbicide to inhibit goosegrass seedling emergence and growth depending on herbicide choice and parts of oil palm frond used.

Emergence; Integrated weed management; Physio-chemical weed control; Shoot fresh weight; Eleusine indica (L.) Gaertn