Why can introduced Achatina and Helix snails damage crops and gardens?

Introduced Achatina and Helix snails can cause significant damage to crops and gardens primarily because they are capable of multiplying rapidly in their new environments.1

When these snails are introduced to non-native areas, their ability to reproduce quickly leads to large populations that can overwhelm local vegetation. For example, the species Helix aspersa is known to plague orange groves in California, and similar introduced species are considered a continual nuisance in home gardens across the United States.1