Etiology and epidemiology of Botryosphaeria canker of Eucalyptus urophylla S. T. Blake in pure stand and an integrated crop-livestock-forest system

Diseases in Eucalyptus plants can reduce forestry production. This study aimed to identify the causal agents of cankers in Eucalyptus urophylla trees in two systems: a pure stand system (PSS) and an integrated crop-livestock-forest system (ICLFS) with Urochloa brizantha. Diseased trees were sampled from trunks, stems, and branches for fungal isolation. Data were collected from two plots per system (500 trees/plot) to analyze disease dynamics, structure, and spatial distribution in the plots and along row directions. Isolates were identified morphologically as Lasiodiplodia spp., Pestalotiopsis spp., and Coniella spp. Phylogenetic analysis of the TEF1-α sequence identified Lasiodiplodia spp. AR2P28 as Lasiodiplodia theobromae and Pestalotiopsis spp. AR1P22 as Neopestalotiopsis surinamensis. Analysis of the ITS sequence identified Lasiodiplodia spp. AR4P15 as Lasiodiplodia citricola. In areas 1, 3, and 4, the disease showed an aggregated spatial pattern, except in P2 of area 1 with a 3x2 quadrat. Area 2 had a random spatial pattern in both quadrat sizes, except for P1 in the 3x2 quadrat. Regarding row direction, areas 1 and 2 had a random pattern, while areas 3 and 4 had an aggregated pattern. The disease had a higher incidence in the ICLFS compared to the PSS, with an increase of 23.6% to 155%. Disease incidence ranged from 34.2% to 87.2%, with fewer foci, mainly compact, and a high number of diseased plants per focus, particularly in areas 3 and 4 in the ICLFS.