Oil-in-water emulsion (EW) of mixed glyphosate isopropylamine (IPA) and triclopyr butoxyethylester (BEE) stabilised by palm-based emulsifiers for weed control

Conventionally,an emulsifiable concentrate (ec)-tiidopyr 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 petroleum- based 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.,2s% 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 c12-18palm methyl esters (pme). the accelerated thermal stability studies at 45°c 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 pim. 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 andor better performance as the commercial herbicide formulations in controlling grassy,broad leaved and woody weeds.