Laboratory Studies of Viral Adjuvants: Formulation Development

Addition of soybean, corn, or cottonseed components and sugars to water-based formulations containing Baculovirus heliothis , the nuclear polyhedrosis virus of Heliothis sp., produced significantly higher mortalities in laboratory tests against 24-hold bollworm, Heliothis zea (Boddie), larvae than did a standard, water-based virus formulation. Formulations containing soybean flour and soybean oil or corn flour and corn oil produced significantly greater bollworm mortalittes than formulations containing only the corresponding oil or flour. Mortalities were not significantly different among citrus pulp, cottonseed, and soybean adjuvant formulations. Bollworm mortality decreased as the percentage of sucrose was increased in increments from 5 to 20% in the soybean flour + soybean oil (SFO) formulation. Substitution of lactose, maltose, or glucose for sucrose in the SFO formulation did not increase mortality but increased costs significantly. Addition of a polysaccharide thickener or ultraviolet (UV) protectant to the SFO + sucrose formulation did not significantly reduce bollworm mortality. The SFO + sucrose formulation was found to be equally effective when volumetric application rates or virus concentrations were varied. The ratio of mortalities caused by adjuvant suspensions containing combinations of soybean flour, soybean oil, sucrose, virus, and water to mortalities caused by virus-water suspension alone usually varied from 6.4 to 15, although one ratio was 55. Estimated cost of the SFO adjuvant (based on current prices, September 1979) at an application rate of 28 liters/ha would be $1.66/ha when an SFO concentration of 2.66 kg/28 liters, or 9.5% (wt/vol), is used.