Studiesonphytopathogensassociatedwithroot rotincassavaarefrequent,unlikethestudyof fungi
associated with stem rot in cuttings, which is the main means of propagation used by
producers. The purpose was to isolate and morphologically and molecularly identify the main
fungi in cassava stem rot. Five cassava varieties (Água morna, Amarelinha, BRS Kiriris, BRS
Poti and São Paulo) from the regions of Eixo Forte and Planalto de Santarém-PA were
evaluated. The material was divided into six rods of each variety, 15 cm long, of which three
underwentsurfacedisinfection(1minuteinalcoholand4minutesin2%sodiumhypochlorite) and
three were not disinfected, being placed in a humid chamber. for 30 days. The fungi were
isolatedinPDAmediumwithamoxicillin,purifiedandthestructuresevaluatedbymicroscopy.
DNAextractionwasperformedfromplateswithpurecolonies.AmplificationoftheITSregion with
ITS1 and ITS4 primers and sent for sequencing. The sequences obtained were edited, contigs
obtained and compared with the sequences deposited in Genbank by BLAST. The
disinfectionprocesswasineffective,asinbothtreatmentstherewasgrowthoffungalstructures,
butitindicatesthatphytopathogensmaybemicroorganismsofendophyticnature.Atotalof47
isolates were obtained: Warm water = 8 isolates; Little yellow = 8 isolates; Warm water -
Plateau = 4 isolates; BRS Kiriris= 17 isolates; BRS Poti= 6 isolates; São Paulo= 4 isolates. In
all varieties, frequent isolates were observed that, through microscopy, were identified at the
genus level as: Lasiodiploidia, Aspergillus and Fusarium. From the sequences obtained, it
revealedsimilarityofidentitywithA.japonicus,A.assiutensis,A.pseudonomius,F.solani,F.
equiseti,Fusariumsp.,L.pseudotheobromae,L.theobromaeandL.brasiliensis.L.theobromae was
the most frequent species, accordingto reports on cassava stem rot.Thegenera Fusarium
andLasiodiplodiaaredescribedassomeofthoseresponsibleforcassavarootrot(dryandblack,
respectively),aswellasotherdiseasesinothercrops.Thisworkdetectedthreegeneraoffungi
associatedwithstemrotinthemunicipalityofSantarém,ofwhichtwoareassociatedwithroot rot.
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