In keeping in our theme of flood related problems, the excess moisture has really added impetus to local snail and slug populations. Slugs and snails are well known in production strawberry fields and home gardens,and I've been seeing a ton of them, including the extremely large example of a common brown garden snail, Cornu aspersum, shown cruising through a strawberry field in the photo below. One very common slug found in the Monterey Bay area is the little grey slug, Deroceras reticulatum. Both of these mollusks can be found on the plant on wet days, at night and usually hide under the plastic or other mulch during the day.
Slugs and snails feed on the leaves of strawberries and occasionally the fruit, and while one might think that these creatures just slurp the fruit down, the feeding is actually a rasping action which ends up with ragged holes in the leaves and fruit. It is important for growers and pest control professionals to distinguish this damage from the clearly margined cuts of lepidopterous larvae, since the control measures for each are quite different (pictures 3 and 4 below).
Certain recommendations for slug control, such as the construction of copper barriers around the planted area and use of beer baits, are appropriate for home gardeners but not economically feasible on a commercial scale. Growers can seek to eliminate hiding places such as rocks, weeds, logs and boards to assist in reducing the numbers of slugs. Furthermore, to avoid slug problems, growers can strive to plant away from areas such as orchards, forested and brushy areas with this sort of debris.
There are also several molluscides for use in strawberry: Deadline M-Ps (Metaldehyde), Deadline Bullets (Metaldehyde) and Sluggo (Iron phosphate).
Growers should be aware that both formulations of Deadline have a number of restrictions as well as hazards to humans and domestic animals which can limit their use in strawberries.
Sluggo is made from iron phosphate and a wheat derivative which serves as bait, Sluggo is non-toxic to humans and other mammals, and has no re-entry, preharvest or application restrictions. It is also OMRI listed for use in organic systems.
The above has been a brief description and evaluation of options available to strawberry growers for the control of slugs. There are several pesticides mentioned here and before using them, read the label and consult your local Agricultural Commissioner if you have any questions.