Slugs

Gastropoda

Grey garden slug
Grey garden slug. Photo courtesy of Cheryl Moorehead. Licensed under CC BY 3.0.
Slugs are the shell-less cousins of snails. They are not picky eaters, and will eat many kinds of plants including most crops. There are many species, but the grey garden slug is often the most damaging.
Slugs come in a variety of colors. They are legless and can be identified by their retractable tentacles and the trail of slime they leave behind.
Grey garden slug
Grey garden slug. Photo courtesy of Joseph Berger. Licensed under CC BY 3.0.
Slugs will eat almost any part of a plant, including seeds, roots, stems, and leaves. They are most damaging early in the season when the seed or seedling is most vulnerable and when cool, wet conditions prevail.
Slugs thrive on the increased crop residue of no-till fields. Tillage will significantly reduce their numbers.