Identification & Incidence: Slugs are soft-bodied animals belonging to a class called Gastropoda (not insects). They range in color from pale cream to gray to shiny black and range in size as adults from less than an inch to over two inches in length. They can damage seeds and seedlings reducing stand and may defoliate established stands that may delay plant development. Slugs damage soybean by destroying the germinating seed prior to emergence and causes significant defoliation.
Sampling: Inspect several areas of the field and determine percentage of plants being fed upon and percent defoliation. Slugs are nocturnal animals and it may be necessary to inspect fields at dusk or after dark to see slugs and determine population densities.
Economic threshold: Treatment may be necessary if defoliation is greater than 40% on slow growing plants or if plants are being killed.
Management Options: Several formulations of metaldehyde are labeled for use on soybean for slug control.