The host-finding ability ofHeterorhabditis heliothidis(Khan, Brooks, and Hirschmann) andSteinernema feltiaeFilipjev in the presence of plant roots in sandy soil was investigated. During a 7-d period, host-finding ability ofH. heliothidiswas not impaired when the dried root weights of corn, tomato, or marigold plants were<1.6 g or ofS. feltiaewhen dried root weights were1.5 g had significantly lower host mortalities (range, 27–50%) compared with control treatments (range, 73–96%); treatments with root weights1.5 g were observed forH. heliothidis, this nematode species showed greater motility, hence greater host-finding ability, thanS. feltiaein the presence of roots because host mortality occurred over a shorter period of time with higher mortality rates and with fewer nematodes.