The introduced slugs and snails are usually gregarious and may cause serious damage as they build up large populations in a local area. In many places, slugs and snails have caused as much damage as insect pests. Eradication and control of slugs and snails is difficult and costly. Slugs and snails are usually nocturnal so their damage is noticed before the pests are. Slugs and snails leave silvery slime trails on the ground and over plants.
Slugs are able to crawl over the sharp edge of a razor blade without harm.
Movement of plant material facilitates the dispersal of these pest snails and slugs. Growers need to examine the plant material as it arrives at the facility. If live snails or slugs in the plant material are noticed, the local Department of Agriculture inspector should be called immediately. Failure to take quick action before the slugs or snails become established at the facility can be costly. For example, in a greenhouse complex in Maryland where the brown garden snail was detected as plant material was being unloaded, the grower took no action.