Organic Amendments and Other Strategies for Management of Meloidogyne spp. and Nacobbus aberrans in Horticultural and Orchard Crops: The Mexican Experience

Plants are subject to infection by many pathogens, including species of bacteria, fungi, nematodes, and viruses. Plant-parasitic nematodes vary in their economic importance in agriculture. Among the most damaging in Mexico there are the species of the root-knot nematodes, Meloidogyne spp., and the false root-knot nematode, Nacobbus aberrans. Such gall-forming nematodes cause millions of dollars in economic losses in different crops throughout the world. The use of chemical pesticides is being restricted in many countries and the development of alternative management practices is imperative. One emerging and promising method is biofumigation, which is centered on enhancing the decomposition in soil of plant residues that release nematostatic and nematoxic metabolites. In this chapter, we have focused on the incorporation into the soil of animal manures and plant materials of the family Brassicaceae, which release isothiocyanates during decomposition, and Sorghum vulgare, which releases cyanogenic glucosides, and the nematicidal and phytotoxic activities of plant extracts. Laboratory studies have demonstrated the toxicity of these metabolites to nematodes. Here, we present a critical review of our studies in control of the gall-forming nematodes using biofumigation with various combinations of the nematode-parasitic fungus Pochonia chlamydosporia, ammoniacal compounds released by poultry and sheep manure, composted plant materials, and vermicompost