Journal of Oil Palm Research Vol. 26 (4) December 2014, p. 366-374

OIL-IN-WATER EMULSION (EW) OF MIXED GLYPHOSATE ISOPROPYLAMINE (IPA) AND TRICLOPYR BUTOXYETHYLESTER (BEE) STABILISED BY PALM-BASED EMULSIFIERS FOR WEED CONTROL

ISMAIL, A R*; NOR FARHANA, N*; MAHIRAN, B**; DZOLKHIFLI, O‡ and HAZIMAH, A H*

ABSTRACT

Conventionally, an emulsifiable concentrate (EC)-triclopyr butoxyethylester (BEE) is tank-mixed with glyphosate isopropylamine (IPA) prior to spray application for the effective control of mixed weeds in plantation areas, such as oil palm and rubber plantations. However, the EC-triclopyr BEE is a petroleumbased formulation that can cause hazards to both the spray operators’ health and the environment. Thus, incorporation of two herbicide actives in the oil-in-water emulsion (EW) system is a new approach to maximise the coverage of weed control and also being safe to the spray operators and the environment. The EW herbicide formulations containing two herbicide actives, i.e., 28% glyphosate IPA and 4.5% triclopyr BEE, were prepared by mixing non-ionic surfactants: DISPONIL OC 25 (or DISPONIL) and Dehydol LS 2EO (or DLS 2) with varying hydrophyl lipophyl balance (HLB) values (10, 11, 12, 13, 14 and 16.5). The oil phase used was C12-18 palm methyl esters (PME). The accelerated thermal stability studies at 45oC for two weeks showed that the EW formulation prepared at HLB 12±1 was the optimum formulation with particles sizes in a range of 13 -15 μm. The EW formulation showed lower surface tensions than the commercially available herbicides, such as Roundup®, Comet, and a mixture of Roundup® and Comet. In biological efficacy studies, the EW-herbicides formulation and the conventional herbicides were applied to Paspalum conjugatum (grassy-weed), Asystasia gangetica (broad leaved-weed) and Clidemia hirta (woody-weed) at the same dose of glyphosate IPA (615 g ai ha-1) and triclopyr BEE (99 g ai ha-1). The EW formulation showed comparable and/or better performance as the commercial herbicide formulations in controlling grassy, broad leaved and woody weeds.

KEYWORDS:


* Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia.
E-mail: ismail@mpob.gov.my

** Chemistry Department, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.

‡ Plant Protection Department, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.