Sentry®, a new antisapstain formulation for protecting logs and lumber. - Part 2: protection of lumber
R N Wakeling, D R Eden, C M Chittenden, J G Van der Waals, B Carpenter, I Dorset, R Kuluz, J Wakeman
Recent research conducted by Forest Research, Chemcolour Industries (NZ) Ltd. and Fletcher Challenge Forest Ltd. has resulted in the development of antisapstain formulations that meet the efficacy requirements of the New Zealand Forest industry for export logs. One treatment, called Sentry®, is now poised for commercial use in New Zealand for treating export logs, having undergone an extensive suite of field and mill trials over a two year period. This paper presents results of field trials set up to determine the efficacy of Sentry® on block stacked radiata pine. Sawn timber was collected from a local mill, sawn into 1 meter lengths, dipped in antisapstain solution, and block stacked prior to assessment of surface fungal degrade after 6, 12 and 15 weeks over a period including a severe hazard New Zealand summer. The higher concentrations of the commercial standards were required to achieve adequate protection of block stacked radiata pine in storage for 12 weeks. After 12 weeks, Sentry®, at the lowest concentration tested (equivalent to 0.125% methylene bis thiocyanate (MBT) plus 0.025% 2-n-octyl-4-isothiazolin-3-one (isothiaz.), gave equivalent protection to the highest concentrations of all the commercial standards (0.6% 3-iodo-2-propynyl butyl carbamate (IPBC) plus 4.8% didecyldimethyl ammonium chloride (DDAC); 0.15% carbendazim plus 0.15% copper-8-quinolate (Cu-8): 0.6% MBT plus 0.6% chlorothalonil). The high level of protection achieved by Sentry® was in part attributed to the broad spectrum of fungicidal activity offered by MBT plus isothiaz. and the micro-emulsion system used.