ESTUDIO EPIDEMIOLÓGICO DE Rhizoctonia solani Kühn EN CINCO GENOTIPOS COMERCIALES DE PAPA (Solanum tuberosum L.) EN NARIÑO.

Context: the potato crop in Nariño, presents a significant number of commercial varieties, but diverse phytosanitary problems like the pathogen R. solani Kühn, affect its production and yield. Knowledge gap: there is no information in the department of Nariño, about the attack of this phytopathogen to different potato genotypes. Purpose: the objective of this research was to determine the damage caused by black scurf [R. solani Kühn] on five commercial potato varieties in the department of Nariño. Methodology: in three potato producing municipalities of the department of Nariño [Ipiales, Pasto and Túquerres], using a Randomized Complete Block Design [with four replications and five treatments] were evaluated these variables: incidence on emergence and sprouting, incidence on harvest, and Commercial yield. Finally, it was carried out analysis of variance, using Tukey's comparison tests. Results and Conclusions: in the locality of Túquerres, the highest percentage of incidence in emergence and sprouting was obtained [36,04%], with statistical differences comparison to the localities of Pasto [30,70%] and Ipiales [31,98%]. For the harvest incidence variable, the Roja Huila genotype [in Túquerres] was the most affected, reaching an incidence percentage of 19,94%. Finally, in the evaluation of commercial Yield, the Superior genotype [in Pasto] presented the best performance, with an average of 22,37 t/ha. [ABSTRACT FROM AUTHOR]