The Mediterranean fruit fly, Ceratitis capitata, is one of the most injurious pests around the world. The common way to control the fly is via poison-bait sprays directed mainly against the females. Hydrolyzed proteins are the customary, but not satisfactory, bait component. Ammonia is the most significant volatile breakdown product of protein decomposition. The relationship between ammonia emanation and the attraction of the medfly was studied earlier and indicated the dependence of attraction on the rate of release of ammonia. The aim of this study was to quantify the rate of ammonia release for optimal attraction of medfly females as a first step in devising a new and more efficient female-attractive bait based on chemically defined components. The rate of release of ammonia was measured in an ammonia trapping system, which was built for this purpose. The ammonia was released from 1 ml sample in a 3-cm-long x 1.5-cm i.d. glass tube. The most attractive concentration of ammonia solution was 0.01 N. The most attractive rate of release of ammonia calculated from the correlation of increasing concentrations of ammonia solutions and their release rates was 14.3 µg/tube/hour. The use of higher rates of release of ammonia up to ~100 µg/tube/hour may be also adequate for use because although they are somewhat repulsive, they are attractive enough to catch relatively higher numbers of flies.
The Mediterranean fruit fly, Ceratitis capitata, is one of the most injurious pests around the world. The common way to control the fly is via poison-bait sprays directed mainly against the females. Hydrolyzed proteins are the customary, but not satisfactory, bait component. Ammonia is the most significant volatile breakdown product of protein decomposition. The relationship between ammonia emanation and the attraction of the medfly was studied earlier and indicated the dependence of attraction on the rate of release of ammonia. The aim of this study was to quantify the rate of ammonia release for optimal attraction of medfly females as a first step in devising a new and more efficient female-attractive bait based on chemically defined components. The rate of release of ammonia was measured in an ammonia trapping system, which was built for this purpose. The ammonia was released from 1 ml sample in a 3-cm-long x 1.5-cm i.d. glass tube. The most attractive concentration of ammonia solution was 0.01 N. The most attractive rate of release of ammonia calculated from the correlation of increasing concentrations of ammonia solutions and their release rates was 14.3 µg/tube/hour. The use of higher rates of release of ammonia up to ~100 µg/tube/hour may be also adequate for use because although they are somewhat repulsive, they are attractive enough to catch relatively higher numbers of flies.