Influencia de los propágulos y el método de inoculación en el desarrollo de la marchitez temprana de la papa causada por Verticillium spp.

Potato early dying is a significant disease in potato-producing countries. However, the development of the disease under different pathogenic conditions and at different times of inoculation is unclear. In this study, the infection of potato plants var. Diacol Capiro by two types of Verticillium spp. propagules, conidia, and microsclerotia (MS), was assessed. Conidia were evaluated based on inoculation of the soil at the sowing time of the tuber, or in soil drench and root immersion 49 days after sowing (das). Microsclerotia were evaluated for their incorporation into soil at different densities at the time of sowing. The tests were carried out under a complete factorial design in a completely randomized arrangement with five repetitions per treatment; the experimental unit was a plant. Non-inoculated plants grown in sterile soil were used as controls in both cases. Variables measured included disease severity, area under the disease progress curve (AUDPC), incubation period, phenological development of the plants, and yield components. Disease incubation periods ranging from 65 to 70 d were recorded when Verticillium spp. was inoculated at the time of sowing. With inoculation at 49 das, the incubation period was reduced to 23 days after inoculation (dai), with lower disease severity than at the time of sowing. The results showed that all inoculation methods, times, and strains of Verticillium spp. caused the typical symptoms of the disease and led to the development of early death. Infection of potato plants was possible with the inoculation of conidia or MS of the pathogen; however, in the latter case, it depended on the inoculum density. While the disease induced by the different inoculation methods led to a reduction in tuber weight, it did not impact the number of tubers produced per plant.