VIEW ARTICLE

Disease Complexes in Tobacco Involving Meloidogyne incognita and Certain Soil-Borne Fungi. N. T. Powell, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27607; P. L. Meléndez(2), and C. K. Batten(3). (2)(3)Research Assistant, and Instructor, respectively, Department of Plant Pathology, North Carolina State University, Raleigh 27607, (2)Present address: Department of Plant Pathology and Botany, University of Puerto Rico, Rio Piedras. Phytopathology 61:1332-1337. Accepted for publication 26 May 1971. DOI: 10.1094/Phyto-61-1332.

Flue-cured tobacco cultivar C 316, susceptible to the root knot nematode (Meloidogyne incognita), was tested in combined inoculations with M. incognita and species of the soil-inhabiting fungi Pythium, Curvularia, Botrytis, Aspergillus, Penicillium, and Trichoderma. Treatments included inoculation with each microorganism alone, as well as inoculation with the fungi separately several weeks after inoculation with M. incognita. Roots showed symptoms of necrosis when subjected to M. incognita in combination with any one of the fungi. Necrosis was especially severe in treatments in which nematodes preceded the fungi by several weeks. None of the fungi induced disease unless M. incognita was present. These observations stress the importance of disease complexes in root breakdown, and emphasize the dominant role of M. incognita as a predisposing agent.