Death results from excessive loss of water. Successful use of metaldehyde baits requires careful application and favorable weather conditions. Slugs often can recover from metaldehyde poisoning if high moisture conditions occur. Also, control is poor during cool periods because slugs are relatively inactive. Apply metaldehyde when the evening is warm and the forecast for the following day is hot and dry.
Young slugs are more susceptible than older slugs.
The range of metaldehyde attraction is limited so spread it throughout the infested area. The amount needed for effective control varies depending on the attractiveness of other food in the area. Metaldehyde is rapidly inactivated by sunlight so spread it underneath leaves late in the day. Sprays of ammonia make excellent contact molluscicides. However, to be effective they must be applied directly to the exposed slugs.