A VEGETABLE OIL-BASED INVERT EMULSION FOR MYCOHERBICIDE DELIVERY

A vegetable oil was used as the major constituent to develop an invert emulsion for use with mycoherbicidal agents. The oil phase (CPWA) con tained soybean oil, a paraffinic spray oil, paraffin wax, and the emul sifying agents Arlacel 780 and Arlacel 989. When mixed with water (50: 50), a stable, relatively low viscosity, mater-in-oil emulsion was for med, which was sprayed onto glass plates and subjected to various envi ronmental conditions to determine the water-retaining properties. This highly stable formulation was capable of retaining 70% of the origina l water content after 20 h of incubation at 22 degrees C and 70% relat ive humidity. Even at 25 degrees C and 40% relative humidity, 40% of t he original water content remained in the sprayed emulsion droplets af ter the same incubation time. When spores of the fungus Ascochyta pter idis, a pathogen of bracken, were incorporated into the formulation an d sprayed onto glass plates, 85% of spores germinated within 20 h and mycelial growth was prolific at 22 degrees C and 70% relative humidity . The efficacy of this formulation on pot-grown bracken was relatively low, with 27.9% necrosis observed after 28 days, due to the particula rly high resistance to fungal attack of this bracken. However, the pot ential of this formulation has been shown and it may be useful for oth er weeds and their respective mycoherbicide agents. (C) 1996 Academic Press,Inc.