Pathogenicity of Pratylenchus coffeae, Scutellonema bradys, Meloidogyne incognita, and Rotylenchus reniformis on Dioscorea rotundata


  • N. Acosta
  • A. Ayala


Low populations (200 specimens per plant) of Pratylenchus cofl'eae, Scutellonema bradys, Meloidogyne incognita, and Rotylenchulus ren(formis stimulated the development of tops, roots, and tubers of Dioscorea rotundata "Guinea" yam. We demonstrated experimentally that P. coffeae was responsible for the deterioration in quality of the yam tuber in Puerto Rico, a condition known as a dry rot of yam. Initial populations of 600 P. coffeae. S. bradys, or M. incognita, and populations of 1,000 P. coffeae or S. bradt's per plant were high enough to induce dry rot of the yam tubers. P. coffeae and S. bradys were pathogenic to yam cultivar Guinea, but M. incognita and R. ren(formis did not cause necrosis or cracking of the tuber cortex in our experiments. Key Words: dry rot of yams, lesion nematode, yam nematode, root-knot nematode, reniform nematode, yam.