The efficacy of two chitinous materials (Clandosan(?) 601 and Clandosan(?) 719) derived from blue crab (Callinectes sapidus) wastes for control of Meloidogyne arenaria was studied in a greenhouse experiment. Both materials controlled the nematode on 'Summer Crookneck' squash (Cucurbita pepo) and on a subsequent planting of 'Rutgers' tomato (Lycopersicon esculentum) when preplant incorporated into soil at rates 10 g/kg of soil. The efficacy of mixtures of urea with Clandosan 601 was explored in a second greenhouse experiment with soil from the same origin. The number of galls/g of fresh squash root (first crop) or tomato (second crop) decreased sharply in response to increasing rates of urea (0-1.0 g/kg of soil) and Clandosan 601 (0-10 g/kg of soil). Treatments with urea alone at rates 0.5 g/kg of soil were phototoxic; however, combination treatments of urea + Clandosan 601 were not phytotoxic. Treatments with urea alone or with Clandosan 601 alone resulted in increased fresh shoot
