Subtropical environments impose conditions of temperature, humidity and rainfall which are optimal for growth of bluestain fungi. Unprotected softwoods under such conditions become bluestained three days after felling. Furthermore, intervals between harvesting and delivery to export marketplaces exceed the 30-day protection periods attributed to anti-bluestain formulations in such conditions. These constraints led to demand for an anti-bluestain formulation with performance which would satisfy customers receiving softwood cargoes in the Far East three months after harvesting in South Africa. The concentrated fungicides were formulated with agricultural adjuvants conventionally used with herbicidal sprays, with surfactants and penetrants to improve wood cover and fibre penetration by the active ingredients, and with stickers to simultaneously retard their loss by leaching. In standard 6-week and extended 12-week laboratory tests one such formulation returned ratings of zero bluestain in Pinus elliottii sapwood discs which had been drenched in water immediately after treatment, and it outperformed all other formulations compared with it. In extensive four-season field trials conducted in Zululand the formulation continued to outperform all those compared with it and provided superior protection of Pinus elliottii and Pinus patula sawlogs from bluestain for 18 weeks. Inspections of a 10,000 m³ cargo of pine sawlogs shipped to Korea and of a similar cargo of peeler logs shipped to Japan supported these findings.

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