Slugs are cryptic terrestrial pests that target a wide range of crops and are especially
damaging to seedlings. Management of these invertebrates mostly relies on synthetic chemistry.
These molecules can be efficient against slugs and snails but can be toxic to other organisms (e.g.,
dogs) and harmful to the environment (e.g., leaching into surface and groundwater). The usage of
pathogenic nematodes has been effective in several crops and European countries. A survey was
conducted to investigate the presence of natural populations of malacopathogenic nematodes in
soybean in the mid-Atlantic region. Slugs were sampled in nine fields across Delaware at various
distances from the field edges (0 m, 5 m, 10 m, 15 m). Soil cover and soil type were also recorded.
Invertebrates were brought back to the laboratory. Slugs were monitored for four weeks, and mortality
was classified into one of three categories: (1) death with the presence of nematodes; (2) death with
the presence of fungi; (3) death without the presence of nematodes or fungi. Nematodes associated
with slugs were identified based on 18S rRNA sequencing. The distance from the field edge did not
impact the number of trapped slugs and the incidence of slug death associated with the presence of
nematodes. Overall, nematodes were collected from ca. 20% of the slug cadavers, and most have
previously been associated with slugs (ca. 35% of deaths associated with fungi and ca. 45% not
associated with nematodes or fungi). The number of captured slugs and slug death associated with
the presence of nematodes were positively correlated with ground cover. Soil type impacted both
the number of captured slugs and the presence of pathogenic nematodes. This survey provides a
first insight into the natural populations of mollusk-associated nematodes in the mid-Atlantic region.
This knowledge may contribute to implementing cultural practices favoring these natural enemies of
slug pests.