Large-scale application of Bayluscide and sodium pentachlorophenate in the Egypt-49 project area. Evaluation of relative efficacy and comparative costs.

A study has been undertaken to evaluate the comparative efficacy of two molluscicides-Bayluscide and sodium pentachlorophenate-in controlling the snail population in a complete watershed and to obtain an analysis of the comparative costs of application. Main canals were treated by the drip-feed method, utilizing the water-carriage system, and other watercourses by spraying. Both molluscicides were found to be highly effective, the snail mortality rates exceeding 98%. Treatment involving a first application in May and June and a second one some five months later kept snail densities very low throughout the year.When costs were compared on the basis of unit volume of water treated, for main canals and other watercourses separately, it was found that the chemical costs were very similar; so were the operational costs for the main canals, but in the other watercourses the cost of applying sodium pentachlorophenate was nearly three times that for Bayluscide. For this reason, and because of the toxic properties of the former compound, it is concluded that Bayluscide is the preferred molluscicide in the Egypt-49 project area and probably also in the rest of the Nile Delta area.