Prospección de plagas, hongos y oomicetos asociados a enfermedades en Cannabis sativa L. en el sur de Uruguay

Growing cannabis for commercial purposes was recently allowed by law in Uruguay. It is grown for different purposes, including medical, industrial and recreational purposes. There are crops in the 19 Departments of Uruguay and they are mostly concentrated in the southern region. There is little information about the diseases and pests of cannabis plants in Uruguay, their potential damage and  management. For this reason, the purpose of this work was to prospect pests and diseases associated with crops in different production types. Farms with field production and with greenhouses were regularly visited, and the laboratory received samples from different production types for different purposes. The sample collection work was carried out in the period from December 2017 to December 2020. The farms were regularly monitored, and visited three or four times, on a case by case basis. Plants with symptoms, signs or damage were observed, and organisms were collected. Disease and pest samples were processed and analyzed in the Phytopathology and Entomology laboratories, respectively, in the School of Agronomy. Microscopic preparations or insect rearing were carried out for pest identification when appropriate. In the case of diseases, samples were analyzed by wet chamber and/or isolation in culture media. Organisms were identified morphologically and in some cases by molecular biology. The organisms identified as potential pests were: Argyrotaenia sphaleropa, Peridroma saucia, Paracles deserticola, Rachiplusia nu, Spodoptera cosmioides, Helicoverpa gelotopoeon, Myzus persicae, Aphis gossypii, Aulacorthum solani, Rhopalosiphum rufiabdominalis, Trialeurodes vaporariorum, Bemisia tabaci, Edessa meditabunda, Nezara viridula, Caliothrips phaseoli, Frankliniella occidentalis, Diabrotica speciosa, Tetranychus urticae y Polyphagotarsonemus latus. Disease-associated species were: Rhizoctonia sp. (root and stem rot) Fusarium sp. (seedling disease, rot of cuttings and seedlings, root rot and in the base of the stem, rot of inflorescences), Fusarium oxysporum f.sp. vasinfectum (rotting of cuttings), Fusarium oxysporum (root and stem rot) Fusarium solani (root and stem rot)Sclerotium rolfsii (withering of plants), Neofusicoccum parvum (canker of stems and branches), Phomopsis sp. (canker of stems and branches), Sclerotinia sclerotiorum (rot stems, rot of branches and inflorescences), Oidium sp. (leaf and inflorescence spot), Alternaria sp. (leaf spot, inflorescence blight), Botrytis cinerea (rotting of cuttings, stems, branches and inflorescences), Fusarium graminearum (inflorescence rot). Cannabis crops in Uruguay are affected by numerous pests and diseases, which are polyphagous or have a wide host range and have mostly been reported as C. sativa pests or pathogens. In this research, no oomycetes associated with C. sativa diseases were isolated.