The fungicide tecnazene (1,2,4,5-tetrachloro-3-nitrobenzene) was added to a nematode infested Norfolk sandy loam at rates of 0, 0.025, 0.05, 0.1, 0.2, 0.4, and 0.5 g/kg of soil, and the soil was immediately planted to cotton. Thirty days later a significant decrease in numbers was recorded for Meloidogyne incognita larvae, Pratylenchus brachyurus, Tylenchorhynchus claytoni, and tylenchoid and dorylaimoid nematodes in soil which had received 0.025 g/kg or higher of the fungicide. Numbers of Helicotylenchus dihystera and Hoplolaimus galeatus were decreased significantly at rates as low as 0.05 g/kg. The number of root knot nematode galls per gram of root was significantly lower in all tecnazene-treated soils. No significant differences in the top weights of the cotton plants were recorded for any of the treatments; however, tecnazene at rates of 0.1 g/kg and above increased root weights significantly.
