Reaction of sweet potato cultivars to foot-rot (Plenodomus destruens) by three inoculation methods in greenhouse

R.B. Pereira, G.B. Amaro, G.C. Lucas, L.S. Mendes, J.B. Pinheiro
Sweet potato foot-rot is considered one of the most destructive diseases of this crop. The pathogen, Plenodomus destruens, causes stem necrosis and root rot, leading to the plant’s death. The aim of this study was to evaluate the reaction of cultivars of sweet potato to P. destruens, using three inoculation methods in a greenhouse. The transplants were planted in pots and inoculated 60 days later, using a suspension of 1.5×106 conidia mL‑1. The following methods were tested: depositing 3.0 mL suspension in the soil near to plant stem; stem puncture, depositing a drop above the first node, and spraying of the stem. The plants were assessed 60 days after inoculation. The experiment was performed in a factorial design with three inoculation methods×six cultivars, in a randomized block design, with five replicates and six plants. There were no significant differences among cultivars for the spraying method, which presented incidences of 3.3 to 23.3%. With the stem puncture method, the ‘Princesa’ cultivar presented incidence of 3.7%, followed by ‘Brazlândia Roxa’, ‘Coquinho’, ‘Beauregard’, ‘Brazlândia Rosada’ and ‘Brazlândia Branca’, with incidences of 30.0, 31.7, 36.7, 43.3 and 61.4%, respectively. On inoculation carried out in soil, the cultivars ‘Coquinho’ and ‘Brazlândia Roxa’ did not differ and presented the lowest incidence, 38.3 and 40.5%, respectively. ‘Princesa’, ‘Brazlândia Rosada’, ‘Beauregard’ and ‘Brazlândia Branca’ did not differ as well among themselves and reported incidences of 60.0, 66.7, 73.3 and 88.1%, respectively. The inoculation in soil was the only method that presented a satisfactory performance, as incidence was higher than 80% in ‘Brazlândia Branca’, used with standard susceptibility.
Pereira, R.B., Amaro, G.B., Lucas, G.C., Mendes, L.S. and Pinheiro, J.B. (2019). Reaction of sweet potato cultivars to foot-rot (Plenodomus destruens) by three inoculation methods in greenhouse. Acta Hortic. 1249, 79-82
DOI: 10.17660/ActaHortic.2019.1249.15
inoculation methods, resistance, Ipomoea batatas

Acta Horticulturae