Sources of inoculum and infection courts of Diplodia gossypina on sweet potato

• Published in: Phytopathology 1988-11, Vol.78 (11), p.1442-1446
• Main Authors: Lo, J.Y, Clark, C.A
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; INFECCIONES; INFECTION; INOCULO; INOCULUM; IPOMOEA BATATAS; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; PERDIDAS POR ALMACENAMIENTO; PERTE AU STOCKAGE; PHYSALOSPORA; Phytopathology. Animal pests. Plant and forest protection; RACINE; RAICES
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/Phyto-78-1442

Diplodia gossypina was isolated from the 1-2-cm base of sweet potato sprouts growing from mother roots that were bedded adjacent to diseased roots, bedded in infested soil, or inoculated with a conidial suspension before bedding. On established vines that were wounded, D. gossypina was recovered 1-2 cm above and 2-4 cm below the point of inoculation 2 mo after inoculation. The fungus was not isolated from the proximal or distal ends of storage roots harvested from field plots in which vine cuttings or established vines were artificially inoculated or when vine cuttings were planted in artifically infested soil. Storage roots harvested from field plots with artificially infested soil had higher disease incidence than roots from noninfested plots. Roots harvested from inoculated vine cuttings or established vines did not differ from the uninoculated control in disease incidence. Freshly harvested storage roots inoculated by placing artificially infested soil on cut ends developed significantly higher disease incidence (16%) than the control (1%). Conidia of D. gossypina survived in field soil for at least 1 yr. Survival of conidia in soil was reduced by high soil moisture. Thus, the pathogen may survive in soil and infect storage roots through wounds made at harvest causing postharvest decay