Slugs are a common pest of peppers and tomatoes. They feed on the lower leaves of young plants and on the ripening fruit. They are often found in gardens that have moist or shady conditions. Slugs primarily feed at night or during overcast and rainy days. Their filelike mouthparts tear plant tissue as they chew. A variety of controls exist to mitigate slugs. Biological, mechanical and chemical controls offer numerous options.
Slug damage is identifiable by the irregularly shaped holes they leave on plant leaves. Usually they feed on leaves that hang closer to the ground and tend to favor younger, more tender leaves. They can, however, crawl farther into the plant and feed on upper leaves as well. Damage is often noted after rains or heavy irrigation. They are attracted to the scent of ripening fruit and can be found feeding on peppers, tomatoes and other fruits and vegetables throughout the season.
Biological and Mechanical Control
Nonchemical controls for slugs include setting traps and applying barriers. You can make traps from flat boards or wet newspaper baited with a piece of potato or cabbage placed underneath. Remove the slugs attached to the bait daily. Traps can also be as simple as a lid or bowl buried in the garden so that the top is flush with ground level. Water with yeast or beer placed within the trap attracts the slugs and they enter and drown. Barriers of copper or diatomaceous earth spread around the perimeter of a garden prevent slugs from entering as well.
Chemical control includes beneficial compounds such as iron phosphate, which if unconsumed by slugs adds fertilizer to your garden, or nonbeneficial compounds such as metaldehyde. Slug killers that contain the compound mesurol are effective for ornamental applications, but should not be used around edible crops such as tomatoes and peppers due to its toxicity.
Deter slugs from feeding on your peppers and tomatoes by selecting a planting site that is less conducive to their presence. A well-drained site in full sun is best for both fruit production and is inhospitable for snails and slugs. Switching to drip irrigation instead of sprinkler or overhead irrigation also deters slugs by keeping the foliage dry and delivering needed moisture directly to the plant's root system. Remove debris from the garden before planting or after the season by raking out leaves and dead plants as this also helps to remove any slug eggs that would have overwintered in your garden.