[Combined and alternate control of Lymnaea truncatula Müller by chemical and biological means. First experimental trials in the field].

Six Lymnaea truncatula stations located in the department of Haute-Vienne (France) were treated in 1984 by a joint and alternate control with the use of a molluscicide (CuCl2), and the introduction of a predator snail, Zonitoides nitidus. Investigations made during the first rainfalls postestivation had showed the elimination of all the lymnaeid snails in five stations, and the presence of some surviving snails (5%) in the last station. The toxic effects of low concentration CuCl2 were enough important for the invertebrates living in the draining ditches of these stations; they were slight for the ones living in the principal draining furrows.