Soft-rot in Tabebuia sp. wood used in water cooling tower:
identification and degradation capacity of the fungi
IRG/WP 98-10253
S Brazolin, M Tomazello, I H Schoenlein-Crusius
Tabebuia sp. (ipe), a native Brazilian wood, is considered of high natural resistance to decaying fungi, and has been used in harsh environments, as cooling towers. Fifty-one fungi, belonging to mitosporic fungi group (Fungi Imperfecti), were isolated from deteriorated Tabebuia sp. wood samples, collected from the mist eliminator and packing of a cooling tower in operation for about 23 years. The degradation capacity of these fungi was evaluated by soft-rot tests using Eucalyptus grandis and Pinus elliottii wood. The microscopic examination of wood sections showed that Acremonium sp., A. kiliense, Phialophora sp. and Phialophora butyrii caused type 1 soft-rot attack in both mod species, while Fusarium oxysporum, Gliocladium spp., Moniliella-like, Penicillium sp., Pullularia pullulans, Trichoderma spp. and Verticillium sp. were not able to produce the same attack. These results and the analyses of weight loss suggested that Acremonium spp. and Phialophora spp. more important decaying organisms of Tabebuia sp. in the cooling tower.