Infection and Morphological Development of Meloidogyne incognita in Roots of Susceptible and Resistant Sweet Potato Cultivars. G. W. Lawrence, Graduate Research Assistant, Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. C. A. Clark, Associate Professor, Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. Plant Dis. 70:545-547. Accepted for publication 13 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-545.

Root systems of the sweet potato cultivars Centennial (susceptible), Jasper (intermediate-resistant), Jewel (resistant), and the breeding line W-51 (highly resistant) were examined at 4-day intervals to determine the frequency of developmental stages of Meloidogyne incognita. The initial rate of juvenile development in Jewel was equivalent to that in Centennial, but the number of juveniles in later developmental stages was reduced. Fewer juveniles entered the roots of Jasper than of Jewel or Centennial, but their subsequent development was similar to that in Centennial. Fewer juveniles entered roots of the breeding line W-51 than those of any of the cultivars, and none of the juveniles reached egg-laying maturity.

Keyword(s): Ipomoea batatas, resistance, root-knot nematode.