These may be planted to divert slugs from feeding on the main Crops. For further control, early every morning remove the slugs from the trap Crops or treat the trap Crops to kill the slugs. Repellents and Barriers Slugs often avoid travelling over acid, alkali or abrasive materials. Diatomaceous earth, wood ashes and similar materials placed around plants provide some protection. However, moisture reduces the effect of these treatments.
Salt also is toxic to slugs and direct applications of table salt to a slug can kill it.
This technique has limited usefulness because excessive salt can affect plants. Certain metal ions also are highly repellent to slugs. Barriers of copper foil exclude slugs from greenhouse benches and raised bed plantings. Other copper-based materials, such as copper sulfate, repel slugs. Molluscicides Pesticides effective against slugs and snails are known as molluscicides.