Comparative field performance of organic and commercial preservatives against blue stain fungi in pinewood

Abstract

The occurrence of blue stain fungi is one of the severe problems in the pinewood industry. This significantly reduces the market value of pinewood due to visible discoloration. This study evaluated the field performance of two plant extract based organic preservatives against boron-based inorganic preservatives for reducing the blue stain fungi development in pinewood. The organic preservatives are locally developed final solution with mud and final solution without mud and inorganic preservatives are commercially available Anti-blue and Anti-boron. The study used freshly cut pinewood specimens exposed for six months at three geographical regions in Sri Lanka i.e. (i) Bandarawela, (ii) Ratnapura, and (iii) Colombo. The effects of location, exposure condition, treatment type, and treatment timing were considered. Specimens were placed under sheltered and non-sheltered conditions, while preservative treatment was applied as early treatment and delayed treatment after cutting. Visible blue stain affected surface area was quantified using an image processing method applied to photographs taken of wood specimens. Untreated non-sheltered specimens in Bandarawela showed the highest visible blue stain development and were therefore used for detailed preservative performance comparison. Sheltered storage reduced visible discoloration compared with non-sheltered exposure. All preservative treatments reduced visible blue stain affected surface area compared with untreated specimens. Final solution with mud performed comparably with the tested commercial preservatives, while final solution without mud was effective but less protective. The findings indicate that early preservative treatment combined with sheltered storage is a practical approach for reducing visible blue stain development in freshly cut pinewood.