An Improved Invert Emulsion with High Water Retention for Mycoherbicide Delivery

An invert emulsion with low viscosity and excellent water-holding properties was developed for delivery of fungal weed pathogens (mycoherbicides). Alternaria cassiae, a pathogen of sicklepod, proliferated after incorporation of spores in the emulsion. The oil phase (CDQ-1) contained paraffin wax, a paraffinic spray oil, and an unsaturated monoglyceride emulsifier (Myverol 18-99). The oil phase was mixed 1:1 (by weight) with water to form the invert, which was sprayed onto glass plates for testing of water retention properties. Water contents ranged from 22% (with A. cassiae present) to 41% (without fungus) for 0.6 to$0.7\text{-}{\rm mm}^{2}$spray deposits after 24-h storage at 21 C and 65% relative humidity. An invert emulsion containing lactofen was prepared using the CDQ-1 formulation.