The Brazilian sugarcane sector has increased the adoption of conservation practices based both on mechanized harvest without burning and on the use of biological nitrogen fixation (BNF) to improve crop sustainability. However, there is no information about the impact of these practices on sugarcane diseases. This study aims at investigating the effect of conservation practices on the incidence and severity of spontaneous sugarcane diseases, considering soil tillage, planting season, residue maintenance, and sources of nitrogenous fertilizers. Two experiments were conducted, being one during the cane-plant cycle and the other carried out throughout the sugarcane cycle until the second ratoon. The simultaneous occurrences of ring spot, caused by Leptosphaeria sacchari Breda de Haan, and red rot leaf infection, caused by Colletotrichum falcatum Went, were the only diseases observed in the experiments regardless of the conservation practices. The use of reduced tillage, conventional tillage, and non-tillage as well as the planting season and the depth of the sugarcane trash layer did not influence the severity of the diseases. However, BNF reduced the severity of foliar diseases in the first and second ratoons. The overall disease severity affected the dry biomass of sugarcane in the first ratoon. The results can assist disease management strategies considering the new scenario of sugarcane production in Brazil.

巴西甘蔗部门已更多地采用基于不燃烧的机械化收获和使用生物固氮 (BNF) 来提高作物可持续性的保护措施。然而，没有关于这些做法对甘蔗病害的影响的信息。本研究旨在调查保护措施对自发性甘蔗病害发生率和严重程度的影响，考虑到土壤耕作、种植季节、残留物维护和氮肥来源。进行了两个实验，一个在甘蔗种植周期中，另一个在整个甘蔗周期中进行，直到第二个宿根。由Leptosphaeria sacchari Breda de Haan引起的环斑同时发生，无论保护措施如何，由Colletotrichum falcatum Went引起的红腐叶感染是实验中观察到的唯一疾病。减耕、常规耕作和免耕的使用以及种植季节和甘蔗垃圾层的深度不影响病害的严重程度。然而，BNF 降低了第一次和第二次宿根中叶病的严重程度。总体疾病严重程度影响了第一个宿根中甘蔗的干生物量。考虑到巴西甘蔗生产的新情况，结果可以帮助疾病管理策略。