Laboratory and field trials of novel antisapstain formulations
R N Wakeling, P N Maynard, D R Eden, C M Chittenden, B Carpenter
This document covers the results of laboratory and field trials of combinations of fungicides formulated using a patented technology (PCT NZ 96/00143). A 3 week laboratory trial that uses radiata pine (Pinus radiata D. Don) branch discs as a substrate was used to determine which combinations possessed a suitable spectrum of fungitoxicity against key sapstain, mould and decay fungi. In particular fungitoxicity against Ophiostoma piceae H & P Syd was looked for as this is the most difficult fungus to control on freshly cut radiata pine in New Zealand. The most promising formulations were then tested using block stacked radiata pine stored for 11 weeks during a high hazard summer period. In general the field trial results corroborated with the laboratory disc trial results. The importance of a broad spectrum of fungitoxicity and in particular a high level of activity against O. piceae, was shown by both types of trial. A formulation containing hexaconazole (0.014%w/v) plus carbendazim (0.028%w/v) plus a quaternary ammonium compound (0.291%w/v) was particularly promising. This formulation achieved significantly better (5% level of probability) control than the commercial standards, for 11 weeks of summer storage. The low fungicide concentrations used auger well for it's cost effectiveness. It is believed that this was in part due to fungicide synergy, broad spectrum activity and the use of microemulsions and solutions of the key fungicide components.