Gray field slug
Common names: Gray field slug, milky slug
Scientific name: Deroceras reticulatum
Counties in California where collected: 24 counties: Alameda, Butte, Calaveras, Contra Costa, Del Norte, Humboldt, Imperial, Kern, Los Angeles, Marin, Monterey, Riverside, Sacramento, San Bernardino, San Francisco, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Shasta, Sonoma, Tulare, Ventura (Roth and Sadeghian, 2006; Mc Donnell et al. 2009).
Ecology: Deroceras reticulatum is one of the most damaging and widespread invasive slugs on the planet. It has a wide ecological range but is most abundant in disturbed environments such as gardens, nurseries, garden centers, garbage piles, parks, roadsides, hedges, ditches, pasture and arable land (Barker, 1999; Mc Donnell et al. 2009). This species is also a very serious agricultural and horticultural pest (South, 1992), targeting seedlings, bulb and flower crops, vegetable crops, and cereals (Godan, 1983; Martin and Kelly, 1986; Thomas et al. 1993; Gordon, 1994 and Barker, 1999).
Description: A medium sized slug up to 50mm (2") in length (Barker, 1999). In California, specimens are predominantly gray but can be cream, both with dark reticulations. Mucus clear but becoming milky-colored when continuously disturbed.