Accelerated testing for out of ground contact using natural biological preconditioning
S Molnar, D J Dickinson, R J Murphy
Small blocks made of Scots pine sapwood were treated, buried in vermiculite and exposed to natural microbial colonisation during outdoor exposure prior to laboratory decay testing. Periodic microbial isolations, moisture content, permeability and weight loss tests were also conducted. Bacteria and moulds colonised the vermiculite and miniblocks well. Aureobasidium pullulans was common on TnBTO treatments. Basidiomycetes were isolated from the control miniblocks at 3 months. Controls showed slightly increased permeability compared with treated samples after 1 month. At 3 months, controls, all TnBTO treated blocks and the lower retentions of DDAC showed permeability increases. Weight loss in the field was low up to three months, even in the controls (3.5%). Agar block trials with no natural pre conditioning showed all preservative treatments were effective, but, after only 1 month's field exposure the lowest retentions no longer provided adequate protection. Further studies are in progress.
Keywords: ACQ; DDAC; TBTO; PROPICONAZOLE; MINI-BLOCKS; FIELD TESTS; HAWAII; SOUTHERN YELLOW PINE