Slugs

Causal Organisms: Deroceras reticulatum (Gray Garden Slug); Deroceras species

Crops Affected: most types of vegetables, strawberries, flowers, and other ornamental plants

Life Cycle:

• Not an insect pest
• Fall under the group of gastropod mollusks, being air-breathing land slugs
  • Note, there are many different types of slugs, many of which are not closely related
  • This particular genus of slugs is listed a plant pest
• Slugs are typically solitary
  • They are most active at night and during cool and humid/damp conditions
  • Slugs burrow in soil or under debris or litter during daytime
  • They protect their bodies from dryness with secretions of mucous
• Slugs are hermaphroditic, which means that they have both male and female reproductive organs
  • Slugs mate in late summer
• Slugs lay colourless to white eggs in fall or in early summer (depending on species) on damp soil or organic matter
  • 30-400 eggs per slug, depending on location, which relates to level of protection offered and environmental suitability of the area
  • Eggs hatch in early spring or summer
  • Most of the offspring will develop, mate, and die in a single season, depending on the location and the species
• Slugs are most prevalent in wet years, in heavily irrigated situations, or where moisture is plentiful

Symptoms:

• All aboveground plant parts may be attacked
• Plant parts may be covered with excrement and slime trails, potentially contaminating any produce, and certainly rendering the plant and produce cosmetically unappealing
• Plants may have split or shredded leaves
  • Marketable plant parts that are fed directly upon may have holes or chewed areas
• Slugs may be also visible on the plant, depending on the species and the conditions

Monitoring:

• Scout for eggs in strawberries by looking under the straw layer
• Watch for adults during active periods
• Watch for evidence of feeding or slime trails

Management:

• Destroy hiding places by burying crop or straw residue
• Remove areas that are damp or shaded
• In small infestations, slugs can be hand picked
• Barriers can be effective in some situations
• Bait traps can be used to attract slugs for removal
  • In high infestations, this may not be effective
• Encourage natural predators, such as mammals, birds, reptiles, and amphibians