Identification and characterization of diseases in Cannabis sativa L

The medicinal Cannabis crop is one of the main growing agricultural activities in Colombia. However, the increase in production areas and the intensification of crops brings a greater predisposition to pests and diseases incidence. The objective of this research was to identify the main diseases associated with a high-density commercial Cannabis crop in a greenhouse. Samples of disease symptoms present in the crop during a round year of production were characterized. Samples were taken in different phenological phases and areas of the farm such as: propagation areas, field production and post-harvest. A total of 43 samples were collected among diseased tissue, soil, compost, substrates, and water. "Damping off" was present in the highest percentage of samples collected from cuttings (28%), followed by samples affected with leaf spot chlorotic halo symptoms (19%). 26 pure isolates of phytopathogenic fungi were obtained, and morphologically and molecularly characterized causing diseases in the crop. They were consistent with Botrytis cinerea (8%), Sclerotinia sclerotiorum (15%), Fusarium sp. (46%), Bipolaris sp. (12%), Rhizoctonia solani (8%) and Corynespora casiicola (8%). Symptoms associated with "Damping off" or wilt tissues revealed the presence of Rhizoctonia solani causing strangulation and cutting rot at the base. Three species of Fusarium were reported: Fusarium fujikuroi, Fusarium oxysporum and Fusarium graminearum, the latter associated with stem end rot. Leaf spot associated with Bipolaris sp. and Corynespora casiicola was present at a high incidence.