Spiegel, Y., Dept. of Nematology, ARO, The Volcani Center, POB 6, Bet Dagan, Israel
Cohn, E., Dept. of Nematology, ARO, The Volcani Center, POB 6, Bet Dagan, Israel
Chet, I., Dept of Plant Pathology and Microbiology, The Hebrew University of Jerusalem Faculty of Agriculture, Rehovot, Israel

Bean and tomato plants were grown in soil amended with Clandosan prepared from crustacean chitin at concentrations of 0.05 to 0.3% (w/w) and inoculated with the root-knot nematode, Meloidogyne javanica. After the first month following inoculation Clandosan caused a decrease in fresh root weight and a relatively small reduction in gall formation, but when the soil was replanted with fresh plants there was an increase in fresh weight and gall formation in beans was precluded almost totally. Chitin itself appeared less phytotoxic and more effective against. M. javanica than Clandosantreated soil during the first month, while the differences in plant and nematode responses to the different formulations were negligible during the second month. In separate experiments, the addition of phosphoric acid-in order to convert NH4 released by the chitin to NH4 +-improved growth of both infected and nematode-free plants. It also reduced phytotoxicity in chitinated plants, especially those which were infected. Corn seedlings were found to be less sensitive to chitin treatment than beans, and tomatoes were the most sensitive. © 1986 Martinus Nijhoff Publishers.