Distribution of (Nematode: Rhabditidae) and Their Gastropod Hosts in California Plant Nurseries and Garden Centers.

Three species of were recovered from 75 nurseries and garden centers in 28 counties in California during fall and winter 2012-2021. A total of 18 mollusk species were recovered, most of them invasive. Nematodes were identified by sequencing the D2-D3 expansion segments of the large subunit (LSU or 28S) rRNA. Based on these surveys, was the most widespread species (37 isolates, 53.6% recovery); followed by (26 isolates; 37.7% recovery); and a closely related isolate (6 isolates; 8.7% recovery). Nematode isolates were mainly collected from four invasive slugs (, , agg, ) and snails ( spp. and spp.). Results suggest that and share an ecological niche in Northern, Central, Coastal, and Southern California, north of Los Angeles County.