Fungal deterioration of a Jesuit South American polychrome wood sculpture

Pigment samples obtained from a South American Jesuit wooden sculpture housed at the Museum of Natural Sciences in La Plata, Buenos Aires province, Argentina, were characterized using scanning electron microscopy and energy dispersive X-ray microanalysis and infrared spectroscopy. The red pigments were identified as vermilion and minium, while the mineral pigment green earth was identified for the first time in a Colonial artwork, together with calcite as the plaster. Two fungal species, Nigrospora sphaerica (Sac.) Mason and Chaethomium globosum Kunze, were isolated from a sample of wood, which was identified as Cedrela fissilis. Chaetomium is a known soft-rot fungus with the capacity to decay wood, but little is known about the effects of Nigrospora on wood. The presence of the two fungi in decayed areas of the wood suggests a contribution of both of them to the degradation of the sculpture.