The molluscicidal properties of Ambrosia maritima L. (compositae). 1. Design for a molluscicide field trial.

The composite plant, Ambrosia maritima is toxic to the snail intermediate hosts of schistosomiasis. A field trial was required to confirm this activity. A preliminary survey of irrigation canals and drains was conducted using two snail sampling methods. The results have been used to indicate the minimum number of watercourses which would have to be treated and the number of sampling stations per watercourse required to establish statistical significance in a kill of snails obtained from a molluscicide treatment.