Effects of molluscicides on seedlings of four grassland plant species.
Abstract
The hypothesis that molluscicides may affect seedling germination and survival, as well as reducing herbivory, thereby influencing the results of experiments in which molluscicides are used to exclude molluscs from plant communities was investigated. The effects of two molluscicides, Fertosan (aluminium sulfate powder) and Draza (methiocarb), on seed germination of four common grassland herbs, Plantago lanceolata, Ranunculus acris, Senecio jacobaea and Taraxacum officinale (grown in pots of John Innes No. 1 compost with mollusca excluded) were examined during a 100-day study. Draza pellets reduced seedling numbers in P. lanceolata, while increasing numbers of R. acris seedlings. The molluscicides, either separately or together, had no effect on numbers of S. jacobaea or T. officinale. The implications of the results are discussed in relation to the interpretation of field experiments where molluscicides are used as experimental tools. The influence of molluscicides on field populations of native weed species in agricultural systems is also discussed.