Enhancement of termite (Reticulitermes flavipes L.) resistance in mycelium reinforced biofiber-composites

The increasing demand for sustainable packaging materials with minimal ecological footprint, compatible cost and stable shelf-life has led to a growing interest in biodegradable or compostable cellulosic packaging materials. Since cellulosic fibers are prone to termite (Reticulitennes flavipes) attack, a study was conducted to identify natural and safe termiticides that can be applied to 100% biodegradable composites derived from lignocellulosic fibers and fungus mycelium. The composite material is a patented technology, developed by Ecovative Design LLC (Green Island, NY). Biocomposite boards of two densities were manufactured using kenaf, hemp and corn fibers and bonded by three different strains of fungi Daedaleopsis confragosa, Ganoderma resinaceum, and Tramates versicolor. The resultant biocomposite boards were evaluated for termite resistance using four termiticides: vetiver oil (Vetiveria zizanioides), guayule resin (Porthenium argentatum), cedar oil (Juniperus virginiana), and borax. The treated boards were evaluated for termite resistance in accordance with ASTM D3345-01. The results showed variable impact of different types of termiticides on fungus mycelium bonded cellulosic biocomposites. A heavy to complete mortality was observed in guayule resin and vetiver treated boards. Borax was least effective as a termiticide. Kenaf and hemp boards treated with guayule resin showed maximum repellency to termites, followed by vetiver oil. The weight loss for treated and untreated samples ranged between 17.4%-33.7%, and 19.9%-55.8% respectively. The findings of this study show that vetiver and cedar natural oils and guayule resin can be used as an effective treatment on mycelium bonded cellulosic composites to improve their termite resistance.