Effect of cinnamic aldehyde on nematode fauna in soil

Various soils infested with plant-parasitic nematodes were mixed with cinnamic aldehyde at the dose of a. i. 2 g/10 l soil as a wettable powder. The treatment decreased Meloidgyne incognita on sweet potato, Ipomea batatas, in sandy soil and okura, Abelmoschus manihot, in loamy aoil, and Tylenchorhynchus claytoni on Kirishima azalea, Rhododendoron obtusum, in silty soil. Helicotylenchus dihystera was not influenced by treatment in either soil. Rhabditid nematodes, especially Pelodera sp., increased greatly in population. Definite trends were not observed for Mononchida and Dorylaimida. The increased or decreased population levels of the above nematodes were observed over a 6-week period after treatment.